Kawai Resonance Issue

Posted by: Bogs

Kawai Resonance Issue - 07/31/12 05:20 AM

Hi everyone! I have a Kawai digital piano and it exhibits the following behavior: when I silently press C then play C# or B, I can clearly hear C resonating as well.
http://www.youtube.com/watch?v=xJreG6BFmX8&feature=youtu.be

I've written an e-mail to Kawai describing the issue and they replied this is normal behavior. Which is weird, because I have C# or B don't have any harmonics in common with C verified up until the 10th harmonic.
https://docs.google.com/spreadsheet/ccc?key=0AmAewoLG-n9AdHROVVJSSjhPN0tLYW5XdDNtN0o5ZFE

I don't have access to an acoustic other than my teacher's piano, so I wanted to know if this behavior is indeed normal or if only Kawai pianos display it. If so, then what is the reason that C also vibrates?

Thank you.
Posted by: Johnkie

Re: Kawai Resonance Issue - 07/31/12 05:48 AM

Yes quite normal .... any acoustic piano would do the same! A broken damper in that area would allow all sorts of harmonics to vibrate in sympathy, and what you're doing is inducing the same effect on your digital.
Posted by: Chris Leslie

Re: Kawai Resonance Issue - 07/31/12 08:51 AM

It is not normal. I can hear the C's fundamental clearly and that should not be. There should only be a wash of various higher overtones of C maybe depending on the other note struck. Does it do the same thing on other notes?
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 11:05 AM

This certainly is not wanted, nor does it serve any harmonic purpose. As far as it being "normal" for this model, you should first determine if it exibits the same thing on other notes also...or is it just this C note. Secondly, try and find out if somebody elses Kawai (same model) does the same thing. There may be some voltage bleed through on a circuit board where two parallel crcuits are not properly insulated from each other. There is no sympathetic vibration going on since this DP uses sampled sound...no physical strings present.
Posted by: Johnkie

Re: Kawai Resonance Issue - 07/31/12 11:14 AM

I'll just shut up then Bogs ..... Clearly I and Kawaii are talking a load of rubbish ! wink
Posted by: maurus

Re: Kawai Resonance Issue - 07/31/12 11:33 AM

Originally Posted By: Johnkie
I'll just shut up then Bogs ..... Clearly I and Kawaii are talking a load of rubbish ! wink


Johnkie, if it's a bit of consolation, I tried to say the same in another thread on the digital piano forum here on PW, with similar success. Goes to show how well people know the instruments they are working with... whistle
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 07/31/12 12:05 PM

Perhaps this is best asked in the digital forum? As this is the acoustic piano forum?

As for acoustic pianos, if properly tuned, John is right. If you hold down C-4, then play E-4, G-4, C-5 etc., all the way up, then every single one of those notes will sound through on that one C-4 which is not being shut off by the damper because you are holding it down. That IS normal. smile It should do it on any key that you choose to play on, however if you play C-4 and make then play D-4, some sound may come through but not like it would if you played notes related to C-4 and probably, not nearly as much so.

I do have to wonder, why in the heck are you doing that in the first place????

I have no idea how it would be on a digital piano because piano tuners (most of us anyway) do not work on these things.
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 12:08 PM

When you write to a company inquiring about their product, there is no guarantee that a qualified person replies with a decent answer. In fact, most companies have a series of defenses you need to wade through to actually get a decent answer from the proper person who knows what they are talking about.

The first line of these defenses are people (often secrataries)known as deflectors. They typically know nothing about the product and throw "canned" form letters or answers back to the inquirer to deflect further inquiries. They don't want to bog down their highest paid employees with customer inquiries. Successive and repeated inquiries will often find their way to the design engineer(s) and quality control folks who have the ability and resources get to the bottom of things and come up with a decent explanation.
A first time call or written complaint/request rarely gets to these people unless its a huge safety or liability issue.
Posted by: Johnkie

Re: Kawai Resonance Issue - 07/31/12 12:24 PM

I am not an electronics wizard by any means, but can't subscribe to "Electronic bleed through" on a digi piano, especially when Kawaii techs have already been asked if this manifestation is a fault. Generally speaking faulty electronic components result in either something not playing at all, or an uncontrollable cipher

My Guess .... and only a pure guess .... is that the guys at Kawaii have researched the properties of acoustic pianos and incorporated this effect to add realism. It is perhaps a little over exaggerated, but I personally do not consider it to be a fault, more part of Kawaiis intended design.
Posted by: Phil D

Re: Kawai Resonance Issue - 07/31/12 12:33 PM

John: Would you really expect to hear the fundamental of C4 if you held the key and pressed C#4 or B3? That is what the video shows, and it is really odd behaviour. I think you might have misunderstood the original post to be honest, or maybe not watched the video?

Don't accept Kawai's original answer, Bogs. Pianos shouldn't do that, nor should digital pianos.

Edit: Never make an assertion without testing it yourself. My piano does indeed exhibit this behaviour. Ignore what I said!
Posted by: maurus

Re: Kawai Resonance Issue - 07/31/12 12:35 PM

But they do. Please, people, sit down at your pianos and try for yourself.

Originally Posted By: Johnkie
My Guess .... and only a pure guess .... is that the guys at Kawaii have researched the properties of acoustic pianos and incorporated this effect to add realism. It is perhaps a little over exaggerated, but I personally do not consider it to be a fault, more part of Kawaiis intended design.


Indeed. And that realism makes sense since the situation is not as rarely occuring as it might seem - after all you get these kinds of 'neighbouring resonances' whenever you play notes with the damper pedal down, or in other situations when you hold a chord with one hand and play something in between with the other. Etc.
Posted by: wouter79

Re: Kawai Resonance Issue - 07/31/12 12:48 PM

Johnkie +1
My acoustic behaves similar.
Posted by: Phil D

Re: Kawai Resonance Issue - 07/31/12 01:13 PM

*shuts up*
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 01:31 PM

If you hold down C on an accoustic piano (to lift off the damper) and play the B or C# to either side of it to ghost a tone, you will not hear the fundamental C ring out.
There may be some incredibly soft very high order partials excited but nothing even close to what your hearing on the DP. This is not an accoustic phenomenom which I think someone would diliberately want to mimic with a DP (exciting a non related harmonic).

I talked with my brother who is an electrical engineer and he confirmed my original suspicians of "bleed through" not being correct on a digital piano (as another poster mentioned). It could easily occur on analogue systems, hi fi's ect...
His suspicians are that its crappy software, if it indeed is not intended to be there. A rogue line of programming or something like that.

So ask the technicians here...
Is the fundamental pitch of C something you want to hear when playing its two neighbouring notes to either side?

Accoustic pianos don't audibly display this if you try to ghost the tone using the immediate neighbouring keys. Wouter, I'm not sure what your hearing, but its not happening on any of the accoustic pianos I just checked it on. Theory supports this since B and C# do not contain the fundamental frequency of C between them.
Posted by: maurus

Re: Kawai Resonance Issue - 07/31/12 01:39 PM

Originally Posted By: Emmery
... its not happening on any of the accoustic pianos I just checked it on.


Emmery, I find this hard to believe.
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 01:49 PM

Originally Posted By: maurus
Originally Posted By: Emmery
... its not happening on any of the accoustic pianos I just checked it on.


Emmery, I find this hard to believe.


Maurus, in order to excite sympathetic vibration on a string the resonant frequency used to do it must match. What frequency in B or C# can excite the fundamental of C which is beside it? No such frequency exists in either of those notes. The closest note below C, to excite its fundamental frequency is the C note, one octave below it...this is a fact.
Posted by: Bogs

Re: Kawai Resonance Issue - 07/31/12 02:16 PM

Thank you everyone for their responses.

Just to make matters clear - what you heard on the video is what happens no matter what key you have depressed, as long as you plan a note a semitone higher/lower, you can hear the depressed key resonating.

The Kawai support guy told me he tested this behavior on Kawai GE-30 and the result is the same. Maurus, who also has a Kawai, said his acoustic piano also exhibits this behavior. I see others here claim the same.

But from the theoretical(physics) point of view, C and C#/B don't share any harmonics [as per the google docs spreadsheet]. It's normal for G and F and E, etc to excite the C strings, but not C# nor B.

Now the question is, are Kawai pianos 'special' and exhibit this behavior? And if so, what is the reason? Someone said the hammer may hit the strings next to it, and thus set it in motion [so no sympathetic resonance involved and thus no violation of the physics laws regarding vibrating strings]. This theory is also supported by the fact that if I silently press C4 on the Kawai digital, C#4 and B3 excite the C4, but neither C#3 nor B2 (also C#5/B4) do.

Any thoughts?
Posted by: maurus

Re: Kawai Resonance Issue - 07/31/12 03:02 PM

Bogs, this is not related to brand at all. Just carefully check any acoustic piano of your choice.

And, as an aside on the physics: A damped vibrating string (all strings in a piano are in fact slightly damped!) does indeed respond to very close neighbouring frequencies.
Posted by: Loren D

Re: Kawai Resonance Issue - 07/31/12 03:16 PM

Maybe Kawai has an algorithm that simulates partials and harmonic overtone so as to enhance the tone and mimic an acoustic. Possible, right?

As others correctly mentioned, this is an acoustic piano forum, and many of us are not digital piano techs.
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 03:32 PM

Well Maurus...

All strings are not damped in a piano. Typically the dampers stop at a point in the treble where strings tend not to have as much sustain as lower notes. I have never seen a piano with dampers going up to C8. What is it that you mean by "slightly damped"? Short sustain is not dampening. Natural decay of a sound on a string is not dampening either.

Secondly, if you notice, I refrain from using generic terms such as "respond" when in fact I refer to a property of a string picking up on another strings vibration as "sympathetic" resonance or vibration. The entire bridge and soundboard of the piano vibrates from one note playing. Many other strings are connected to the same bridge (segment) and vibrate at the bridge connection because of their physical connection. Only the undamped strings will pick up on this connection and only if they share the same frequencies and partials of the excitation frequency. Properly dampened strings will not produce audible sympathetic vibrations of this nature....thats why they are damped.

They do not however, all sympathetically vibrate at like pitches unless they share the fundamental frequency or partial ladder. Hold down C5 and play C4 (staccato)and you will clearly hear the fundamental of C5 excited by C4's first partial (along with numerous other coincidental partials farther up the ladder).
If you do the reverse however and hold down C4 and strike C5...you will hear C4's first partial excited...not its fundamental...C5 does not have the coincidental frequency to do so...its lowest frequency is twice that of C4's lowest frequency.

Now using unrelated notes such as B or c# to excite the fundamental frequency of C that lies next to it, will simply not work. THEY SHARE NO COMMON FREQUENCY WITH C'S FUNDAMENTAL. You may hear a very faint busy mix of super high partials way up the ladder, if they happen to be coincidental, but definately nothing clear or concise and DEFINATELY NOT THE FUNDAMENTAL FREQUENCY OF C AS HEARD IN THE DP.

Posted by: BDB

Re: Kawai Resonance Issue - 07/31/12 03:38 PM

If I try it on my pianos, I get a lot of noise out of the C, with a definite bias towards the C pitch. I would think that there is enough coupling of energy through the bridge to excite the string, and most of it will be in C. It is not as strong as if I hold the C and play the C an octave above it, however.
Posted by: Johnkie

Re: Kawai Resonance Issue - 07/31/12 03:40 PM

Perhaps rather than saying "this shouldn't happen" it would be better to think of possible reasons why in fact .... it does!

Sympathetic vibrations and harmonics are without doubt part of the overall character of pianos, but adjacent notes being influenced might well be the result of closeness of frequency. When there is relatively little difference between adjacent notes, it may be more a case of a phase shift causing an interference beat that excites the non-played note.

This would account for the lack of like similar behaviour if trying to emulate the same scenario using octaves above and below .... their frequencies being way to far from the resonant frequency of the un-played note.

I can see that kawaii (and other excellent manufacturers) have most likely tried to be as close as possible to the real thing, but whereas an acoustic piano needs quite a powerful strike on an adjacent key to get this effect, digitals tend to have software designed to trigger certain results, on a "if that .... then this" type of senario.

If I had anything to do with improving digital piano software design, I would be looking at linking the velocity side of the design to match more closely the effect on adjacent notes .... more so in the bass and tenor sections where frequencies are closer.

Lets not get into a running battle though ..... I'm just thinking out loud wink
Posted by: maurus

Re: Kawai Resonance Issue - 07/31/12 04:15 PM

Emmery (and Johnkie and others). If one starts to do physics, one should get the physics right. In terms of physics every string that loses some of its energy to its surroundings, by whatever mechanisms, is what physicists call a "damped" oscillator. (That has nothing to do with the dampers in a piano.) And the physics tells you that any damped oscillator does not only react to (= acquires energy from) harmonic vibrations that reach it, but to frequencies very close to its fundamental mode as well. (*In addition*, there is the response of the string to the noises made by the hammer when hitting strings closeby, and other complex effects, depending on the construction and the circumstances. That response leads to an excitement of certain overtones in a given string, just as BDB reports.)

But whatever physics tells you, you have hands to play and ears to listen to your piano(s).

I will leave the matter here, have fun with the thread.
Posted by: Emmery

Re: Kawai Resonance Issue - 07/31/12 04:18 PM

Has it occured to you that C# or B have no harmonic/musical connection to C. Nor do we as tuners use two attached semitones as a tuning interval. Also, manufacturers strive to hit the string with the hammer near the node point of an unwanted but naturally occuring partial (eg. C3- A#5 or D6). What logic would there be to have the sound of C3's fundamental in the mix of C#3's sound or vice versa? I can't imagine a software engineer deliberately trying to do this.

I just checked my C3 note with MatLab spectrum analyser and it's fundamental does not show after trying to excite it with B2 and C#3. My ETD RCT is not picking up on it either with full gain and the mike cranked up. Most importantly, I'm not hearing it either.

I would however love to hear any accoustics/physics/scientific explanation or formula that explains how non coincidental frequencies bring out sympathetic vibration or resonance in an object or string in a supportive manner. The imput of the vibration would have to be equal to the natural resonance of the object to build sound...anything other than this would cancel it by vibrating out of frequency with the resonance pattern.
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 07/31/12 04:34 PM

I still want to know, why in the heck anyone would want to do this in the first place? What purpose does it serve?
Posted by: BDB

Re: Kawai Resonance Issue - 07/31/12 04:35 PM

One more experiment pretty much confirms what I said. Playing a note adjacent to a note that is held silently will excite the silent note through energy transferred mechanically. The proof of this is to hold a note at the break, and try the adjacent note on the same bridge and the adjacent note on the other bridge. The one on the same bridge will make the note held silently sound louder than the one on the other bridge, which has a more distant mechanical connection.
Posted by: ando

Re: Kawai Resonance Issue - 07/31/12 04:41 PM

You could describe it this way: when you first strike this adjacent key, there is a sudden pressure wave that is somewhat close to the frequency of the adjacent note. If you hit this note VERY hard and staccato, you can induce a very small amount of movement in an adjacent string. It's not the same thing as sympathetic resonance however. Achieving a note in an adjacent string requires you to make the excitation note very short, because if it is allowed to keep vibrating for a time, it will interfere destructively with the adjacent note. This effect is reliant on the non-struck string not being able to really "see" the frequency of the string that is exciting it. If you try it, you can hold down a B and belt a C really hard and short, you will hear a faint B coming through. This is caused by this pressure high wave which can induce movement in the string. If you do the same thing, but hold the C for a couple of seconds, the B will pretty much disappear. That's because the frequencies are unable to couple, instead they cancel. There is nothing to sustain the B. Real sympathetic resonance involves genuine coupling of frequencies and it will continue for as long as both notes are free to ring.

I would consider it a waste of time to bother trying to incorporate this effect in a digital piano. It also comes through far too loud in the clips of the Kawai. This is a problematic emulation of sympathetic resonance. Of course, you can turn the resonance down on a DP, but that punishes the resonances that should be relatively strong - octaves and fifths.
Posted by: KawaiDon

Re: Kawai Resonance Issue - 08/02/12 12:56 AM

Duplicate post - Piano World was reporting database error.
Posted by: KawaiDon

Re: Kawai Resonance Issue - 08/02/12 12:57 AM

Bogs, I'm wondering - did you try turning off the sympathetic resonance in the digital? I do not work with digital pianos much, but I have used some of our digital models and this is an adjustable parameter. The functions in the digitals are made to simulate the sounds created in acoustic pianos as closely as possible.

Now Emmery wrote: <When you write to a company inquiring about their product, there is no guarantee that a qualified person replies with a decent answer. In fact, most companies have a series of defenses you need to wade through to actually get a decent answer from the proper person who knows what they are talking about.

The first line of these defenses are people (often secrataries)known as deflectors. They typically know nothing about the product and throw "canned" form letters . . . . . . etc.>

Emmery, I don't know where this comes from, but it is a load of nonsense, to put it politely. It amazes me to read these kind of statements made in forums stating vividly imagined fiction in an emphatic and authoritative manner.

First of all, there are no "secretaries" at Kawai. All technical support calls for digitals go directly either to an electronics technician who knows the products inside and out (Juan), or to the person who is responsible for developing the sounds and functionality of the instruments, Alan. There is also a parts person to take parts orders. All technical support calls for pianos go directly to a piano technician (there are 3 at Kawai America including me), or to a parts specialist. If a call or e-mail goes to the wrong person, everyone in the company knows to forward it directly to the correct person in service, and no one would do anything resembling what you wrote.

So Emmery, back off a little and realize that piano companies are staffed by people just like you. Kawai and other piano makers are not huge corporations with layers of staffing intent on deflecting issues. All of us have the attitude that solving a problem is much better for everyone than letting it go unresolved.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/02/12 10:22 AM

Don, my posting on how many companies operate to handle questions/complaints was generic, even though it was within the topic of a Kawai related issue. Its just something people have to watch for these days. From your explanation, Kawai seems to handle this better than most companies. Try getting technical advice on a Young Chang/Kurzwiel DP and you will know what I mean by the term "deflection".

Still, I find it highly doubtful that a service tech, design/software engineer, and programmer are one in the same person or that any of these specific professions (Kawai or anyone else) requires full competancy/training/related qualifications, of the other two. It is still worthwhile to try and make sure one is talking to the right person, or confirm that the company is delegating questions/complaints to the right people. Eg. Programmers can verify if an engineering spec was properly executed in the software. Engineers can verify if the foundations of the specs are in line with what the product is supposed to do. Technicians in the field can replace circuit boards, diagnose problems ect..

The answer given to the OP by Kawai that the sound heard on playing those notes is "normal". This does not indicate if it was intended by design, or just a byproduct of other factors (flawed programming or an adjustable setting for eg.) Squeaky body parts on a 1970 Vega is pretty "normal" if you ask a mechanic or an owner of one. GM certainly didn't intended it to be by design.

On acoustic pianos numerous things are done to lessen or eliminate unwanted sounds or harmonics. Cloth is woven into parts of strings to dampen them, hammer strike point coincides with node locations of unwanted partial(s), scaling design tries to lessen inharmonicity, tone issues or uneven downbearing. I think its far fetched to believe a DP will try to incorporate into its design something which an accoustic piano manufacturer effectively went out of their way to eliminate. Certainly not to the degree that can be heard in the OP's sound sample. Besides, there are numerous other wanted things they are still trying to emulate off accoustic pianos and not being 100% succesful with.
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 08/02/12 10:58 AM

Don is right. I've called Kawai, Yamaha, Steinway, Bosendorfer, Young Chang, Baldwin and many other companies lots of times over the years for various reasons. I have always gotten the right person from the start, have always gotten answers and good ones at that to any and all questions that I had to ask, particually at Kawai and Yamaha.

I always get my calls returned, emails answered in full and have been extremely happy with their vast knowledge which is way more than mine in many cases which I readily admit. That's one of the reasons we call them after all, with questions and problem solving if we do not have the answer along with other things that we encounter that we need help with or for warranty issues---the go ahead to fix it sign from them.

I have no complaints whatsoever about the technical department at Kawai and I've dealt with them A LOT over the years. They are great listeners that will add my input or suggestions toward solving any future problems that may exist if what I suggest helps....

Don in particular, has always been extremely helpful and gracious with his time with him with any and all questions or issues that I have brought up and, we have solved all of them between us.

I still wonder, why a person would do this to a piano or anything else in the first place? Again, what purpose does it serve?
Posted by: maurus

Re: Kawai Resonance Issue - 08/02/12 11:07 AM

Originally Posted By: Jerry Groot RPT
I still wonder, why a person would do this to a piano or anything else in the first place? Again, what purpose does it serve?


Once again: Because it simply can't be avoided in an acoustic piano. Listen to your instruments.

And why would a DP manufacturer emulate this? Because he wants a realistic simulation of the acoustic piano. - Of course there are many acoustic effects around in a piano, and the choice of the ones to emulate is always debatable.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/02/12 11:27 AM

maurus, I can pick up the fundamental tone of that C note in the sound clip with my spectrum analyzer, with my ETD, and audibly with my ears. This is coming via my computer speaker. I can't pick up that same frequency on my 2 acoustic piano with any of the equipment, or my ears. Okay, so maybe some people pianos exibit this slightly more where they can. I doubt however that its as loud as the sound sample, or contains just the one frequency.

Also, introducing an additional frequency into a tone which is based on +/- the 12th root of 2 serves no harmonic/musical purpose. Additionally, piano performers are not taught to, nor does any musical score indicate to strike a key on the piano so slowely/softly to not sound it...there is no "Zero Forte". Its an impractical application because a played and held note can sustain up to 10-15 seconds on its own. Most importantly, the DP would display this same phenomenom if the sustain pedal was held down...because an acoustic piano would. Holding that C key down or applying the sustain are the same thing... a process that lifts off the damper.
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 08/02/12 11:28 AM

I must have missed your reply the first time. wink

But, holding a note down, slowly letting it down, then playing surrounding notes around it, most certainly can be avoided. That part, is intentional and is what I'm wondering about. What for, how come? smile .

And yes, holding one note down, and playing others around it will elicit strange sounds from other places in the piano. So long as the damper is lifted, even your voice will come through more strongly on certain notes than on others. wink
Posted by: maurus

Re: Kawai Resonance Issue - 08/02/12 11:36 AM

Ah, perhaps I misunderstood your question, Jerry. Of course it is indeed rather improbable that someone silently presses a key and then plays around it. But in experimental music you never know - I've heard many interesting things. And, closer to the usual things: (1) Play a chord, say F major, hold it with one hand, and play some black keys in between - what gives? Or: (2) Use the sostenuto pedal. smile

A piano is a terribly complex instrument, and one should never say never. It does what it does.

PS. I really don't know what's up with Emmery's ears or instruments...
Posted by: Emmery

Re: Kawai Resonance Issue - 08/02/12 12:43 PM

maurus, even the 30th partial off a string is present in a string's sound. Do we recognizably hear it? No. Do DP's emulate it, no. Do we use it in tuning intervals? No. If we eliminated it, would it matter? No.

The complex, wide spectrum energy from the hammers impulse can move via the bridge/soundboard over to another note to induce vibration in it...and not just the string beside it. Its just not very loud, nor is it supportive, because it does not share sympathetic resonance the way ghosting tones do with related string harmonics.

There are numerous sounds which are present on an accoustic piano which are not even related to strings. The bump sound of a key stick on the balance rail precedes the string sound by several thousandths of a second. This is more evident and easier to reproduce on a DP (same tone), yet to date, DP manufacturers haven't bothered to.

So why would they reproduce an un related, non harmonic, non sympathetic tone on only adjacent keys, and not have the sustain pedal do the same, or do it the same way on all keys. This minute sound would also be there from non adjacent keys also. Wave energy does not decrease with the inverse square law in solid objects like the bridge, as it does in air.
Posted by: Chris Leslie

Re: Kawai Resonance Issue - 08/03/12 04:16 AM

Although I cannot get this effect on my piano, or others when I thought of it, I happened to try it today on a 60s Rogers and got the effect at about the same level intensity as in the video irregardless of using staccato jabs or not - (Ando). So there you go: some do, some don't.
Posted by: Bogs

Re: Kawai Resonance Issue - 08/03/12 05:26 AM

Originally Posted By: Chris Leslie
So there you go: some do, some don't.


It's what I think too. But the question still remains why some do and some don't. We've heard possible explanations why they do:
1. mechanical energy is transferred to the adjacent string by the not-rigid (free to vibrate) parts of the piano
2. an undamped string is influenced by frequencies very close to its own ( first image on the right ) - although I have my doubts about his one, I'm waiting for a qualified person to comment

Now why are there pianos that don't exhibit this behavior? Both no.1 and no.2 easily apply to all pianos...

P.S: I wish everybody would cooperate and that this thread would not turn into 'I'm right, because I can hear it on my piano'/'You're wrong, because I can't hear it on mine'. This is the reason I posted this in the piano tuners section, because I though people here would deal with a lot of pianos, not just their home one [the Piano section] and thus not be biased.

I'm also not interested if this is wanted or not - good or bad, I would like to know why it's audible on some and not on others
Posted by: Withindale

Re: Kawai Resonance Issue - 08/03/12 09:09 AM

Originally Posted By: Bogs
Originally Posted By: Chris Leslie
So there you go: some do, some don't.


It's what I think too. But the question still remains why some do and some don't. We've heard possible explanations why they do:
1. mechanical energy is transferred to the adjacent string by the not-rigid (free to vibrate) parts of the piano
2. an undamped string is influenced by frequencies very close to its own ( first image on the right )

I'd look for natural resonances in each piano, as suggested by the first para of your Wikipedia reference.

In physics, resonance is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others. These are known as the system's resonant frequencies (or resonance frequencies). At these frequencies, even small periodic driving forces can produce large amplitude oscillations, because the system stores vibrational energy.
Posted by: Olek

Re: Kawai Resonance Issue - 08/03/12 10:00 AM

natural "resonances" occur also from dampened strings. on tall verticals damping is not very efficient (as it was on first old forte pianas)

But even when it is, I blieve that some reaction remain from the damped strings, that can participate to the tone of the played notes
Posted by: Bogs

Re: Kawai Resonance Issue - 08/03/12 11:15 AM

Originally Posted By: Withindale
I'd look for natural resonances in each piano, as suggested by the first para of your Wikipedia reference.


But this behavior happens for all the notes! It's not just the (C,C#), (C,B) combination, it's all (tone, semitone) combinations. So natural resonances are ruled out.
Posted by: Withindale

Re: Kawai Resonance Issue - 08/03/12 11:38 AM

Bogs

You asked why some acoustic pianos and not others produce tones from adjacent strings that are not sympathetic vibrations. Please clarify why you rule out natural resonances.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/03/12 12:19 PM

Ian, natural resonances and sympathetic vibration only occurs when an identical or extremely close identical frequency is exiting an object. A truck passing on the street can cause a window pane to rattle on anearby home. The rattling will stop when they change speeds or gears on the vehicle.

When a note is struck on the piano and another note is undampened, the other note gets two distinctive types of excitation. The first to occur is the shock force from the hammer being transfered via the string to bridge to soundboard and the solid construction of these materials convey this initial attack force energy to other strings. This initial wave energy is not structured harmonically like strings are, and is extremely wide spectrum as far as frequencies go. It will create "noise" on another string but it lacks the transverse force of a hammer hit to really create any significant amplitude. This force is physically conveyed through the termination points (ends of the speaking length of the string) not at an ideal anti node location like where a hammer hits.

A secondary vibration energy occurs after this attack on the initially struck string and it does follow a structured spectrum of specific harmonics. This too will convey energy via the parts of the piano, as well as through the air around it. This energy will produce resonance and sympathetic vibration if it closely matches in fequency on any of the harmonics/partials. Two adjacent notes don't share any close harmonics on the lowest most audible portion of the ladder. This is why the sound some people are hearing is so faint in comparison to resonant produced sound on related notes.

On the pianos I listened to for these effects on adjacent notes, I actually pick up a lot more high fequency excitation than I do recognizable lower partials. It could be that high order partials might be close enough to each other because of varying inharmonicity that accompanies them, or, and I'm speculating here...the unstructured force wave of the initial hammer impact conveys a strong portion of high frequency energy in its spectrum.

Posted by: Olek

Re: Kawai Resonance Issue - 08/03/12 12:49 PM

you also could hear some of the wave produced by the back and forth move of the bridge (quadratic effecr is the name) but this is supposed to produce frequencies that are fundamental x 4 (or x2, I am just unsure).

What I heard is out of the spectra, so it can be longitudinal waves. Try to rub the strings with a resin impregnated cloth if you want to be sure. ( that isw a mean to evaluate moe of a string)
Posted by: Withindale

Re: Kawai Resonance Issue - 08/03/12 02:08 PM

Emmery, agreed.

Your analogy with trucks and windows is a good one. The window rattles because it has a certain predisposition to do so.

As you will know better than me, the actual frequency spectra of piano notes can be far from the regular set of partials one might expect. There are the quadratic effects and longitudinal waves that Kamin mentions, along with phantom partials and other effects related to the bridge, soundboard resonances, etc.

Going back the Wikipedia quote, which puts it well, even small periodic driving forces can produce large amplitude oscillations at some unexpected frequency or other.

I have no idea why that Kawai digital piano sounds as it does or why any acoustic piano should behave in a similar way across the keyboard.
Posted by: Loren D

Re: Kawai Resonance Issue - 08/03/12 03:21 PM

Why anyone considers Wikipedia even remotely reliable is beyond me. Seriously.
Posted by: Minnesota Marty

Re: Kawai Resonance Issue - 08/03/12 04:15 PM

Originally Posted By: Withindale
Emmery, agreed.

Your analogy with trucks and windows is a good one. The window rattles because it has a certain predisposition to do so.

.


The analogy is not a good one as it is not an example of sympathetic vibration. It is an example mechanical vibration. The window pane rattles because it is loose in its frame, not because it is sympathetic to another source. The mechanical energy is being supplied by the passing truck, transmitted through the ground, into the house, and to the window frame which rattles the glass in contact with the window frame. The speed of the truck, or the gearing, would have no effect as the resonant fundamental frequency of the glass pane is far above the mechanical frequency of the truck. The glass pane rattles, and thus creates its own sonic projection.

A sympathetic vibration, at the same fundamental as the glass, with sufficient amplitude projected, would cause the glass to shatter and not rattle.
Posted by: Withindale

Re: Kawai Resonance Issue - 08/03/12 05:15 PM

Originally Posted By: Minnesota Marty
Originally Posted By: Withindale
Emmery, agreed.

Your analogy with trucks and windows is a good one. The window rattles because it has a certain predisposition to do so.


The analogy is not a good one as it is not an example of sympathetic vibration.


Marty, you are right in general, but Emmery's window was exhibiting sympathetic vibration for the sake of the argument!
Posted by: Withindale

Re: Kawai Resonance Issue - 08/03/12 05:23 PM

Originally Posted By: Loren D
Why anyone considers Wikipedia even remotely reliable is beyond me. Seriously.


Yes, you need to be judicious, but the passage I quoted is correct.

The Tahoma Bridge disaster is a famous example of natural resonance.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/03/12 05:30 PM

I believe you are incorrect Marty, the window pane is a good analogy of sympathetic vibration. If you google it specifically with the + sign and "sympathetic resonance", the exact analogy is present in numerous physics, science and acoustic articles...along with Wikipedia (under "sympathetic resonance"). It was not my own analogy, I was simply aware of it from reading it numerous times over the years.

The front hood on automobiles are actually constructed in such a way to avoid the same resonance caused from engine noise. Because it uses so much flat sheet steel, it needs to be constructed in a way to withstand the engines' entire RPM range.
Posted by: Olek

Re: Kawai Resonance Issue - 08/03/12 05:31 PM

Originally Posted By: Minnesota Marty
Originally Posted By: Withindale
Emmery, agreed.

Your analogy with trucks and windows is a good one. The window rattles because it has a certain predisposition to do so.

.


The analogy is not a good one as it is not an example of sympathetic vibration. It is an example mechanical vibration. The window pane rattles because it is loose in its frame, not because it is sympathetic to another source. The mechanical energy is being supplied by the passing truck, transmitted through the ground, into the house, and to the window frame which rattles the glass in contact with the window frame. The speed of the truck, or the gearing, would have no effect as the resonant fundamental frequency of the glass pane is far above the mechanical frequency of the truck. The glass pane rattles, and thus creates its own sonic projection.

A sympathetic vibration, at the same fundamental as the glass, with sufficient amplitude projected, would cause the glass to shatter and not rattle.


I believe you have the point ther..(while I heard windows vibrating with piano tones )I will try to test more tomorrow, but yet, what I hear is either longitudinal waves exited by the bridge, ore a mix of high partials creating new sounds (those are not high treble ringing, and certainly not a little segment of wire exited somewhere)

It is easy to test so to know which sound is heard..
There is also indeed a part of fundamental exited just because the bridge vibrates enough (small grand Pleyel) clearly audible, on a large part of the scale for those last)

All those unsuspected tones are what makes the sound of real pianos lively and rich.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/03/12 05:42 PM

Originally Posted By: Kamin

...All those unsuspected tones are what makes the sound of real pianos lively and rich.


....or sound rinky tink, like many spinets.
Posted by: Chris Leslie

Re: Kawai Resonance Issue - 08/03/12 06:20 PM

Originally Posted By: Jerry Groot RPT

I still wonder, why a person would do this to a piano or anything else in the first place? Again, what purpose does it serve?


If some pianos have this effect then there may be implications for the sonority of the piano when using the sustain pedal. I would imagine increased cacophony if many adjacent un-dampened notes are more easily excited at their fundamental.
Posted by: Minnesota Marty

Re: Kawai Resonance Issue - 08/03/12 10:27 PM

It is not a good analogy as a rattle of a window pane is not caused by sympathetic vibration. Rattle is the key word. A "rattle" is due to mechanical vibration, through direct, or conveyed, contact with the source of the mechanical energy.

I need not check additional sources in reference to my expertise in the properties of acoustic dynamics.
Posted by: DoelKees

Re: Kawai Resonance Issue - 08/03/12 10:52 PM

Originally Posted By: Emmery
nor does any musical score indicate to strike a key on the piano so slowely/softly to not sound it...

Check out "Musica Ricercata" by Ligeti which does just that often esp. in the first two pieces which are the only ones I can play.

I would guess to enhance "realism" they just added a cheap tweak to excite other notes a bit when you strike any key. Sounds more random, i.e., like the real thing.

Kees
Posted by: Emmery

Re: Kawai Resonance Issue - 08/04/12 12:48 AM

Originally Posted By: DoelKees
Originally Posted By: Emmery
nor does any musical score indicate to strike a key on the piano so slowely/softly to not sound it...

Check out "Musica Ricercata" by Ligeti which does just that often esp. in the first two pieces which are the only ones I can play.

I would guess to enhance "realism" they just added a cheap tweak to excite other notes a bit when you strike any key. Sounds more random, i.e., like the real thing.

Kees


Kees, I've heard linguolabial trills with more depth and musical quality than what Musica Ricercata has to offer...I'm sad to say. When an artist gathers enough recognition to put out trash or nothing as an example of their work...the only thing more silly are the critics who waste their breath talking about it.

Its in the same league as Cages' 4' 33" (opening and closing the piano lid)....

http://www.youtube.com/watch?v=HypmW4Yd7SY

and Robert Rauschenbergs' "White Paintings"...




Posted by: DoelKees

Re: Kawai Resonance Issue - 08/04/12 12:59 AM

Originally Posted By: Emmery
Originally Posted By: DoelKees
Originally Posted By: Emmery
nor does any musical score indicate to strike a key on the piano so slowely/softly to not sound it...

Check out "Musica Ricercata" by Ligeti which does just that often esp. in the first two pieces which are the only ones I can play.

I would guess to enhance "realism" they just added a cheap tweak to excite other notes a bit when you strike any key. Sounds more random, i.e., like the real thing.

Kees


Kees, I've heard linguolabial trills with more depth and musical quality than what Musica Ricercata has to offer...I'm sad to say. When an artist gathers enough recognition to put out trash or nothing as an example of their work...the only thing more silly are the critics who waste their breath talking about it.

Its in the same league as Cages' 4' 33" (opening and closing the piano lid)....

http://www.youtube.com/watch?v=HypmW4Yd7SY

and Robert Rauschenbergs' "White Paintings"...





Tastes differ. I like Musica Ricercata quite a bit and so did Stanley Kubrick who used it (mvmt 2) in his last movie.

Regarding Cages' 4' 33" I performed it once in a version lasting 3 minutes (4'33' is just the title, the piece can be any length) on recorder (the piece is for any instruments, not piano as many people think). Instead of closing the piano lid during the piece as David Tudor did I took my recorder apart.

Needless to say it was tuned in an unequal temperament. smile

Kees
Posted by: Olek

Re: Kawai Resonance Issue - 08/04/12 03:31 AM

I like LIGETI probably pne of the best composers, much humor, no much posture .

I hate "music" that have as a prerequisite to put the metronome at 120
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 10:25 AM

Originally Posted By: Bogs
[...] I don't have access to an acoustic other than my teacher's piano, so I wanted to know if this behavior is indeed normal [...]


Well, I was just going to lurk, but I had to try this on the two working pianos I have at hand. The effect is very clear on the Lester spinet. After testing C4, I played a few other random keys, and G4 rings very prominently when held silently and the adjacent semitones are played. So, I went to the Haddorff upright. The C4 does not ring very prominently when tested this way (though it does ring), and, when tested, G4 rings very prominently against the semitones. I am not educted enough to speculate on the cause--mechanical, sympathetic, angelic. Anyway, Bogs, thought you'd want to know. It seems that it is a property of my two old acoustic pianos, at least, and from a previous discussion in Pianist Corner, I will throw my hat into the ring with those who suppose that what you discovered is a deliberate decision by the DP designers to try to get the right piano noises into the DP...

--Andy
Posted by: Emmery

Re: Kawai Resonance Issue - 08/04/12 12:25 PM

Originally Posted By: Minnesota Marty
It is not a good analogy as a rattle of a window pane is not caused by sympathetic vibration. Rattle is the key word. A "rattle" is due to mechanical vibration, through direct, or conveyed, contact with the source of the mechanical energy.

I need not check additional sources in reference to my expertise in the properties of acoustic dynamics.


Just about every disaster and miscalculation involving the oversite of "experts", was preceded with the famous words in your quote I have put in bold. The expertise of the numerous people using the definition I used is known...you not bothering to verify it does not make it invalid..other than in your own mind. Your own "expertise" however appears self proclaimed, and not important enough to even put in your signature.

Marty, the word "rattle" has numerous different meanings definatively. "to make a rapid succession of short sharp noises" is the most common, and it is not quantified with a source of the noise being mechanically coupled, or indirectly through air pressure waves, nor any other mode of transmission, resonant or not. Its use in "resonance" explanation therefore is not definatively excluded.

I have heard snare drums "rattle" in the same way as window panes do, and it can be sympathetic resonance or simply excitation from a drumstick. The contact of the drum skin to the snares produces the sound, the sympathetic resonance of the skin or the snare can be the source of the driving amplitude for it. Air pressure waves of resonant frequency from a nearby speaker can induce it. Non resonant vibration forces from a stage floor can also induce it...neither excludes the other, in regards to a "rattle" being heard.
Marty, the cited definition bothers you in regards to accuracy because perhaps you are ignoring a key componant of it. The fact that the "rattle" occurs as the engine speed of the truck is at a specific RPM, and then dissapears when this RPM slows or speeds up is what defines its resonant relationship. If the truck produced a vibration that caused a rattle, regardles off engine speed, then I would agree with you that there is some other mechanical vibration going on that is not sympathetic in nature.
Posted by: BDB

Re: Kawai Resonance Issue - 08/04/12 12:31 PM

This topic has become an argument about diction, the choice of words, rather than a discussion of the physics of piano sound.
Posted by: Emmery

Re: Kawai Resonance Issue - 08/04/12 12:36 PM

Originally Posted By: BDB
This topic has become an argument about diction, the choice of words, rather than a discussion of the physics of piano sound.


Exactly. Sometimes when one reaches into a bag of weapons and finds none there, they resort to using the bag as a club.
Posted by: Olek

Re: Kawai Resonance Issue - 08/04/12 12:57 PM

1 / 1 ; the window can also vibrate because bass frequencies carry more in solids than in air. indeed in both cases it is resonance. I suggest that the whole panel of the window is large enough to react to some low frequencies.

some kind of tuning of the windows occur there. ..

in the pian the bridge vibrates at different rates, the neighbour strings only react when the rate is enough for them.
then it sound its fundamental frequency, only exited by the bump of the hammer. If you put a finger on the bridge you can feel the vibrations. the neighbour strings filter and tunes the vibrations of the bridge...
hence my point a global better soundong of pianos :
with high level of consonance
with springy pins and lively upper segments.
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 08/04/12 02:35 PM

Originally Posted By: Chris Leslie
Originally Posted By: Jerry Groot RPT

I still wonder, why a person would do this to a piano or anything else in the first place? Again, what purpose does it serve?


If some pianos have this effect then there may be implications for the sonority of the piano when using the sustain pedal. I would imagine increased cacophony if many adjacent un-dampened notes are more easily excited at their fundamental.


Holding down a note intentionally making it not play, and then seeing how many surrounding notes you can get to sound through it, or how many you cannot make sound, and then complaing about it, wondering if that is normal, is ridiculous. It is not normal to do that to begin with.

That, in and of itself, serves no useful purpose for the playing of the instrument. That was my point. What pianist plays the piano that way anyway? None that I know of.
Posted by: BDB

Re: Kawai Resonance Issue - 08/04/12 03:19 PM

Stravinsky's Serenade en La uses silently depressed notes to hold certain sounds, as do a number of pieces by other composers. The most notable piece is Ives' Concord Sonata, which calls for a block of wood to hold a cluster of notes. Even Paganini from Carnival by Schumann plays a bunch of loud chords with the pedal, and then plays another chord almost silently, which is held while the pedal is let up. The latter chord is heard without attack.
Posted by: Minnesota Marty

Re: Kawai Resonance Issue - 08/04/12 03:29 PM

Emmery,

My credentials in the field are not relative to the general discussions at Piano World. I clearly state my name and location in my signature line.

If you must know, I hold a Master of Science in Acoustical Engineering from Loyola University. I need not defend my statements to you. Your window analogy is flawed for the reasons I have noted. My credentials are not derived by means of Google.

This is a discussion group. My curriculum vitae is not prerequsite to my participation in this forum. My musical credentials also are not necessary for participation in these forums. Those credentials are the intellectual and practical basis for my skill as a performing pianist and do not require posting on a billboard.

When you venture into analogy based on flawed scientific deduction, your misconception should be presented to the forum. I did just that.
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 04:21 PM

Originally Posted By: BDB
This topic has become an argument about diction, the choice of words, rather than a discussion of the physics of piano sound.


Don't they all, eventually? This one just happened sooner than most. Hitler. I will say, though, I am so glad for your most recent post, BDB, regarding the holding down of keys, silently, in a musical context per composition per recognized great composers.

Did you learn something, Jer? wink

P.S. What an awesome thread!

(Thanks Horowitzian! grin )

P.P.S. I like Leghetti, too, especially with CHAS sauce.
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 05:04 PM

Originally Posted By: Kamin
1 / 1 ; the window can also vibrate because bass frequencies carry more in solids than in air. indeed in both cases it is resonance. I suggest that the whole panel of the window is large enough to react to some low frequencies. [...]


I suggest the window needs to be re-glazed with Fletcher Terry Glazier Push Points, which distribute weight better than traditional 08-111 Diamond [shaped] Fletcher Terry Glazier Point for Professional Driver No. 1. These particular push points should be used wherever windows are glazed on truck routes, imho. Then, we can get back to talking about why adjacent strings vibrate. (BTW, DAP latex window-glazing-in-a-tube glazing compound is not the same as DAP '33' glazing compound in a tub. Very, very different compounds with very different properties. Wholly different, in fact..., although they both hold the window in, ultimately...)*

Upon further testing on the Lester, I noticed that B2 and C#3 made silently held C4 ring. I also noticed that B4 and C#5 made an upper partial of silently held C4 ring. Someone please learn me. Or, at least, school me. Or, at the very least, teach me.

Thank you, Jer, for leRnin' me where B0 starts.

And, I do mean leRnin'.

_____
* Did I just split an infinitive??!? Or, what? (ala Edie Arlisa Brickell)
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 05:11 PM

Phew. BO stinks! Good thing B0 doesn't! In most cases. Unless tuned incorectly.*

_____
*and I do mean incorectly.
Posted by: pianoloverus

Re: Kawai Resonance Issue - 08/04/12 05:55 PM

Originally Posted By: BDB
Stravinsky's Serenade en La uses silently depressed notes to hold certain sounds, as do a number of pieces by other composers. The most notable piece is Ives' Concord Sonata, which calls for a block of wood to hold a cluster of notes. Even Paganini from Carnival by Schumann plays a bunch of loud chords with the pedal, and then plays another chord almost silently, which is held while the pedal is let up. The latter chord is heard without attack.
Which means that what Jerry said is true only 99.9999999999999999999999999% of the time.
Posted by: Jerry Groot RPT

Re: Kawai Resonance Issue - 08/04/12 06:04 PM

Hahaha!!! 99.999999 % of the time. I like to be right that much! smile ,

Funny Andy!

I'm setting thinking BO or, BS? haha.

Some people (idiots in my opinion) also compose music to be played in chords in the lowest octaves of the piano. That makes the piano sound horrible tuning wise, to me and to most reputatble technicians. We get the nost complants from people playing the piano in the manner. Does that mean the piano should be played that way then? Just because someone wrote something for it or, thought of it? Or, thinks it sounds good?? Noooooo but, they do it anyway... Hey, I know, I might as well use my iPAD for a cutting board! There's an idea! smile Whatever blows your hair back.... Once again, I say, what useful purpose does the OP have for doing what he is doing? I repeat. No useful purpose.

By the way, I lost my glasses recently today, as a matter of fact, so I can barely see what I am typing let along what you said so if there are more than usual, mistakes, da'ts what fer how come! I blind bat now... frown

Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 06:23 PM

Originally Posted By: Jerry Groot RPT
[...] Hey, I know, I might as well use my iPAD for a cutting board! [...]

ROTFL!!! laugh laugh laugh *

_____
*Is that "diction"?
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 06:32 PM

Originally Posted By: Jerry Groot RPT
[...] Does that mean the piano should be played that way then? Just because someone wrote something for it or, thought of it? Or, thinks it sounds good?? [...]


What if...

Somebody composed something because their tuner tuned their piano a certain way, and it sounded good because of the way the composer composed it because of the way the tuner tuned it?!? Tonal Temperament (TT), anyone? Anyone????

grin
Posted by: BDB

Re: Kawai Resonance Issue - 08/04/12 06:46 PM

There is a sonata for a 5 + 7 tuned piano in one of Owen Jorgensen's book. The piano is tuned with the 5 black keys equal tempered and the 7 white keys equal tempered, as opposed to the 12 chromatic keys being equal tempered. Then there is Harry Partch's music, using a 69 note per octave just intonation, not for piano, but he did tune some harmoniums that way. There are also a number of pieces for quarter tones, sometimes with pianos especially made, sometimes with two pianos.

All of these are probably less successful than the various ways of using resonances within a piano. After all, that has always been available, and the most important pedal on the piano, the damper pedal, relies on them.
Posted by: Cinnamonbear

Re: Kawai Resonance Issue - 08/04/12 07:29 PM

Originally Posted By: BDB
There is a sonata for a 5 + 7 tuned piano in one of Owen Jorgensen's book. The piano is tuned with the 5 black keys equal tempered and the 7 white keys equal tempered, as opposed to the 12 chromatic keys being equal tempered. Then there is Harry Partch's music, using a 69 note per octave just intonation, not for piano, but he did tune some harmoniums that way. There are also a number of pieces for quarter tones, sometimes with pianos especially made, sometimes with two pianos.

All of these are probably less successful than the various ways of using resonances within a piano. After all, that has always been available, and the most important pedal on the piano, the damper pedal, relies on them.

Ha-ha-ha! Sometimes, BDB, you are truly amazing! smile
Posted by: Emmery

Re: Kawai Resonance Issue - 08/04/12 09:38 PM

Originally Posted By: Minnesota Marty
Emmery,

My credentials in the field are not relative to the general discussions at Piano World. I clearly state my name and location in my signature line.

If you must know, I hold a Master of Science in Acoustical Engineering from Loyola University. I need not defend my statements to you. Your window analogy is flawed for the reasons I have noted. My credentials are not derived by means of Google.

This is a discussion group. My curriculum vitae is not prerequsite to my participation in this forum. My musical credentials also are not necessary for participation in these forums. Those credentials are the intellectual and practical basis for my skill as a performing pianist and do not require posting on a billboard.

When you venture into analogy based on flawed scientific deduction, your misconception should be presented to the forum. I did just that.


First of all Marty, this discussion was originally dealing with peoples thoughts, analogies and theories on a decent subject. You claim I made an analogy with the window pane that was incorrect. I responded that the analogy is not mine, found in countless text books, articles, citations, Wiki ect...

Instead of making a valid explanation of your view, or actually looking to see why exactly this analogy is used by countless experts, you abondon everything by suddenly claiming your expertise puts you beyond all that. You brought in credentials, I didn't.

Like I said, if a truck engine vibrates at a specific rpm, and a window on a nearby home rattles because of it, but then stops when the rpm changes, that is sympathetic resonance. Called an acoustical engineer in Guelph, he also confirms the analogy is correct. He also confirmed that an mechanical vibration that isn't sympathetic (as you claim) will rattle that window through a wide range of frequency. Marty, you are missing this important difference. Non sympathetic vibration will work in a wide frequency range...the analogy mentioned states the opposite.
Posted by: Minnesota Marty

Re: Kawai Resonance Issue - 08/04/12 10:39 PM

Originally Posted By: Emmery
Originally Posted By: Minnesota Marty
Emmery,

My credentials in the field are not relative to the general discussions at Piano World. I clearly state my name and location in my signature line.

If you must know, I hold a Master of Science in Acoustical Engineering from Loyola University. I need not defend my statements to you. Your window analogy is flawed for the reasons I have noted. My credentials are not derived by means of Google.

This is a discussion group. My curriculum vitae is not prerequsite to my participation in this forum. My musical credentials also are not necessary for participation in these forums. Those credentials are the intellectual and practical basis for my skill as a performing pianist and do not require posting on a billboard.

When you venture into analogy based on flawed scientific deduction, your misconception should be presented to the forum. I did just that.


First of all Marty, this discussion was originally dealing with peoples thoughts, analogies and theories on a decent subject. You claim I made an analogy with the window pane that was incorrect. I responded that the analogy is not mine, found in countless text books, articles, citations, Wiki ect...

Instead of making a valid explanation of your view, or actually looking to see why exactly this analogy is used by countless experts, you abondon everything by suddenly claiming your expertise puts you beyond all that. You brought in credentials, I didn't.

Like I said, if a truck engine vibrates at a specific rpm, and a window on a nearby home rattles because of it, but then stops when the rpm changes, that is sympathetic resonance. Called an acoustical engineer in Guelph, he also confirms the analogy is correct. He also confirmed that an mechanical vibration that isn't sympathetic (as you claim) will rattle that window through a wide range of frequency. Marty, you are missing this important difference. Non sympathetic vibration will work in a wide frequency range...the analogy mentioned states the opposite.


I am missing nothing. If you really called one of my colleagues (unnamed), you obviously did not quote your own analogy exactly as written. Your analogy is incorrect and I have pointed out exactly why. You are now tempering it in an attempt to prove it true. Many of the things you have stated, are defending a premiss which is not the original.

I was the one who brought up credentials?

Originally Posted By: Emmery
Your own "expertise" however appears self proclaimed, and not important enough to even put in your signature.


If the truck changes gears, the window will still rattle. I does not negate the mechanical vibration being transmitted to the window frame. The intensity of the rattle may change or even stop. It has nothing to do with sympathetic vibration. There may, in fact, be minor resonance between the glass and the truck, but it is mechanical vibration, not sympathetic vibration, causing the glass to rattle.

You are wrong. You need not attempt to teach what I have already learned through formal education.

Please send me the bibliography of your sources to substantiate your claim.
Posted by: DoelKees

Re: Kawai Resonance Issue - 08/04/12 11:19 PM

Originally Posted By: Minnesota Marty

If the truck changes gears, the window will still rattle. I does not negate the mechanical vibration being transmitted to the window frame. The intensity of the rattle may change or even stop. It has nothing to do with sympathetic vibration. There may, in fact, be minor resonance between the glass and the truck, but it is mechanical vibration, not sympathetic vibration, causing the glass to rattle.

A loose window in a pane is a highly nonlinear system and the usual concepts of resonance don't quite apply. Rattling can occur at pretty much any frequency, but only if the excitation force is just right. You basically bounce the glass back and forth between its points of attachments. With a higher force you can make it rattle at a higher frequency.

For linear systems this is not true. The resonance response is directly proportional to how close the excitation frequency is to the natural resonance of the system and is independent of the excitation force.

I guess this shows that piano's are complex nonlinear systems, not easily emulated by digital keyboards.

Long time ago I was woken up in Holland by a rattling window which I assumed was caused by a truck which was not supposed to be allowed to drive through the narrow street I lived in.

It turned out to be caused by a small earthquake caused by gas extraction cave collapse some 100 Km away. It had just the right frequency and force to make it happen.

Kees (Credentials available on request)
Posted by: Olek

Re: Kawai Resonance Issue - 08/05/12 06:13 AM

Originally Posted By: pianoloverus
Originally Posted By: BDB
Stravinsky's Serenade en La uses silently depressed notes to hold certain sounds, as do a number of pieces by other composers. The most notable piece is Ives' Concord Sonata, which calls for a block of wood to hold a cluster of notes. Even Paganini from Carnival by Schumann plays a bunch of loud chords with the pedal, and then plays another chord almost silently, which is held while the pedal is let up. The latter chord is heard without attack.
Which means that what Jerry said is true only 99.9999999999999999999999999% of the time.


How good to go with the flow then ! (I dont trust your number anyway)
I just cannot understand how, a piano technician, that is supposed to work for and with musicians, may belive that music may be some basic 3 or 4 chords and simple tunes derived from religious hymns for the main part.

That is so much of a simplified ,reduced point of view on the richness of our world that it escapes me. (I believe it is due to early mind programming)

When looking at it more closely even the origins of those actual standards where richer, rhythmically speaking most often but also from melody point of view.

End of the rant

I just heard yesterday a radio program on Alan Lomax & family , very interesting samples of treasures from the past.
Posted by: Olek

Re: Kawai Resonance Issue - 08/05/12 06:33 AM

Originally Posted By: Minnesota Marty
Originally Posted By: Emmery
Originally Posted By: Minnesota Marty
Emmery,

My credentials in the field are not relative to the general discussions at Piano World. I clearly state my name and location in my signature line.

If you must know, I hold a Master of Science in Acoustical Engineering from Loyola University. I need not defend my statements to you. Your window analogy is flawed for the reasons I have noted. My credentials are not derived by means of Google.

This is a discussion group. My curriculum vitae is not prerequsite to my participation in this forum. My musical credentials also are not necessary for participation in these forums. Those credentials are the intellectual and practical basis for my skill as a performing pianist and do not require posting on a billboard.

When you venture into analogy based on flawed scientific deduction, your misconception should be presented to the forum. I did just that.


First of all Marty, this discussion was originally dealing with peoples thoughts, analogies and theories on a decent subject. You claim I made an analogy with the window pane that was incorrect. I responded that the analogy is not mine, found in countless text books, articles, citations, Wiki ect...

Instead of making a valid explanation of your view, or actually looking to see why exactly this analogy is used by countless experts, you abondon everything by suddenly claiming your expertise puts you beyond all that. You brought in credentials, I didn't.

Like I said, if a truck engine vibrates at a specific rpm, and a window on a nearby home rattles because of it, but then stops when the rpm changes, that is sympathetic resonance. Called an acoustical engineer in Guelph, he also confirms the analogy is correct. He also confirmed that an mechanical vibration that isn't sympathetic (as you claim) will rattle that window through a wide range of frequency. Marty, you are missing this important difference. Non sympathetic vibration will work in a wide frequency range...the analogy mentioned states the opposite.


I am missing nothing. If you really called one of my colleagues (unnamed), you obviously did not quote your own analogy exactly as written. Your analogy is incorrect and I have pointed out exactly why. You are now tempering it in an attempt to prove it true. Many of the things you have stated, are defending a premiss which is not the original.

I was the one who brought up credentials?

Originally Posted By: Emmery
Your own "expertise" however appears self proclaimed, and not important enough to even put in your signature.


If the truck changes gears, the window will still rattle. I does not negate the mechanical vibration being transmitted to the window frame. The intensity of the rattle may change or even stop. It has nothing to do with sympathetic vibration. There may, in fact, be minor resonance between the glass and the truck, but it is mechanical vibration, not sympathetic vibration, causing the glass to rattle.

You are wrong. You need not attempt to teach what I have already learned through formal education.

Please send me the bibliography of your sources to substantiate your claim.


Please guys, you are not wrong none of you, I get the difference now, you are in semantics...

I wish however to see the credentials wink a scan of the diplomas would be perfect, with id card, passport, may be some genetic imprint, so I will be sure I exchange with a knowledge person !!! wink
Posted by: Minnesota Marty

Re: Kawai Resonance Issue - 08/05/12 11:58 AM

Hi Isaac,

I have sent you my blood sample for the required DNA testing.

Posted by: Emmery

Re: Kawai Resonance Issue - 08/05/12 12:24 PM

Originally Posted By: Minnesota Marty
Originally Posted By: Emmery
Originally Posted By: Minnesota Marty
Emmery,

My credentials in the field are not relative to the general discussions at Piano World. I clearly state my name and location in my signature line.

If you must know, I hold a Master of Science in Acoustical Engineering from Loyola University. I need not defend my statements to you. Your window analogy is flawed for the reasons I have noted. My credentials are not derived by means of Google.

This is a discussion group. My curriculum vitae is not prerequsite to my participation in this forum. My musical credentials also are not necessary for participation in these forums. Those credentials are the intellectual and practical basis for my skill as a performing pianist and do not require posting on a billboard.

When you venture into analogy based on flawed scientific deduction, your misconception should be presented to the forum. I did just that.


First of all Marty, this discussion was originally dealing with peoples thoughts, analogies and theories on a decent subject. You claim I made an analogy with the window pane that was incorrect. I responded that the analogy is not mine, found in countless text books, articles, citations, Wiki ect...

Instead of making a valid explanation of your view, or actually looking to see why exactly this analogy is used by countless experts, you abondon everything by suddenly claiming your expertise puts you beyond all that. You brought in credentials, I didn't.

Like I said, if a truck engine vibrates at a specific rpm, and a window on a nearby home rattles because of it, but then stops when the rpm changes, that is sympathetic resonance. Called an acoustical engineer in Guelph, he also confirms the analogy is correct. He also confirmed that an mechanical vibration that isn't sympathetic (as you claim) will rattle that window through a wide range of frequency. Marty, you are missing this important difference. Non sympathetic vibration will work in a wide frequency range...the analogy mentioned states the opposite.


I am missing nothing. If you really called one of my colleagues (unnamed), you obviously did not quote your own analogy exactly as written. Your analogy is incorrect and I have pointed out exactly why. You are now tempering it in an attempt to prove it true. Many of the things you have stated, are defending a premiss which is not the original.

I was the one who brought up credentials?

Originally Posted By: Emmery
Your own "expertise" however appears self proclaimed, and not important enough to even put in your signature.


If the truck changes gears, the window will still rattle. I does not negate the mechanical vibration being transmitted to the window frame. The intensity of the rattle may change or even stop. It has nothing to do with sympathetic vibration. There may, in fact, be minor resonance between the glass and the truck, but it is mechanical vibration, not sympathetic vibration, causing the glass to rattle.

You are wrong. You need not attempt to teach what I have already learned through formal education.

Please send me the bibliography of your sources to substantiate your claim.


Marty, because the original topic in the posting has to do with resonance, the analogy I copied copied and presented had to do with resonance. Resonance phenomena can occur from mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions. Sympathetic resonance will occur from mechanical conveyance of the energy along side of non-sympathetic resonance. This is why the rattle can occur at a specific frequency and diminish or dissappear at different frequencies.

The part I put in bold in your quote is incorrect. Mechanical resonance can also be sympathetic. It is a specific frequency where the input mechanical vibration matches the resonant frequency of the object and/or its interface with another object closely and the natural dampening qualities of the object is reduced or negated. I
In the case of a rattle on a window which is not solid in its frame is dependant on the clearance between them. A wide clearance will correspond to a slower frequency, a narrow clearance will respond to a higher frequency. It this case the resonance is based on the interface of the two objects.

On a piano, the wide spectrum frequencies of the hammer blow attack (not the string harmonics) are being mechanically conveyed through the bridge to other strings. If part of that spectrum matches the natural resonant frequencies of another string, these will become more pronounced comparatively. A buzz from a loose rib can also occur at specific frequencies and this too is dependant on the fit between them.


Posted by: Withindale

Re: Kawai Resonance Issue - 08/05/12 01:12 PM

Originally Posted By: Emmery
On a piano, the wide spectrum frequencies of the hammer blow attack (not the string harmonics) are being mechanically conveyed through the bridge to other strings.


A possible explanation for adjacent strings becoming excited is mechanical transfer through the bridge and soundboard system:
  • The impulse resulting from the hammer strike produces some movement of the bridge in the string direction.
  • This movement produces smaller movements at the adjacent strings.
  • Those movements are sufficient to set the adjacent strings vibrating.
Whether this effect will happen or not depends on the piano. My piano does not exhibit it but Phil's does. Kawai say the GE-20 does and Maurus hears it on his Shigeru Kawai SK-2.

As Kawai try to make their digital pianos sound as realistic as possible by "harmonic imaging", it seems the effect results from the design and construction of their grand pianos.

I wonder if adjacent notes sounding off was intentional or an accidental by-product of some other design goal.
Posted by: maurus

Re: Kawai Resonance Issue - 08/06/12 02:41 AM

Originally Posted By: Emmery
Kees, I've heard linguolabial trills with more depth and musical quality than what Musica Ricercata has to offer...I'm sad to say. When an artist gathers enough recognition to put out trash or nothing as an example of their work...the only thing more silly are the critics who waste their breath talking about it.

Its in the same league as Cages' 4' 33" (opening and closing the piano lid)....

http://www.youtube.com/watch?v=HypmW4Yd7SY

and Robert Rauschenbergs' "White Paintings"...




Interesting to what lengths this thread about a rather simple phenomenon has gone. And thanks for pointing out your aesthetic preferences to us, Emmery.
Posted by: Olek

Re: Kawai Resonance Issue - 08/06/12 09:52 AM

WHen I was younger there where window panel tuners, it was queite a common profession.

They pass in the streets ringing a bell and singing "window tuner" , "window tuner" .

They used a trcuck engine mounted on a dolly to detect which panels wher vibrating and wt which frequencies so they could adapt the technology used to the kind of vibrating detected.

Unfortunately all those simple and traditional trades have been lost today, the adoption of less noisy exhaust systems have ruined them. just a few remain around airports



BTW some of my my windows ring at the B1 C2 range, because of the surface of the panel probably.