Piano World Home Page Forums Our Most Popular Forums Piano Forum FAQ - Piano Forum Duplex-like thingies on Bösendorfer, Grotrian, Petrof, Samick, and Nordiska

Here is a patent application that uses the terminology as I understand it. An aliquot is not a duplex, but as curry points out is a "stop" that allows the duplex to form.

A duplex can be in front or in back.

A duplex is a freely vibrating portion of the string that is not struck.

http://www.freepatentsonline.com/5736660.html

I don't see why either the Boesendorfer, or the Grotrian freely vibrating portion would not be called a duplex. Granted, non-tuned.

A search of the US patent and trademark database shows that there is no trademark on the term "duplex scale" or "duplex" near "scale".

A search of the copyright database shows that the term "duplex scale" has not been copyrighted either.

I will check my old 19th century piano tuning/maintenance books to see what usage "duplex scale" had back then later tonight. (That sounds impossible.)

Derick,
Thank you for the information regarding the front duplex on the Bosie Imperial.
Since I'm sure that you know how to post pictures could you post some of the front duplex on your piano?

I'm sure that you can also find a Mason & Hamlin somewhere to try and pluck the duplex segment. You'll find that on this design of the tunable duplex the tone lasts for a LOT longer then microseconds.

Roy and Curry,
In my first post on this thread I wrote this:
Now, the fact remains that of the modern and relatively newly designed pianos that are found in the group of "performance " pianos by the Larry Fine book (tiers 1 and 2) the vast majority of designers decided to incorporate the duplex scale system on their instrument unless they have a single stringing design that goes all the way up the treble.

If a certain designer of modern pianos decides NOT to incorporate this method into his instruments for one reason or another it is well within his rights. There is no right or wrong in this regard.

There is no reason though to discount the contribution many believe the duplexes have, including the rear duplexes, just because the designers of these instruments are not posting on this forum.
The fact remains, that designers of modern instruments at Mason & Hamlin, Fazioli, Estonia, C.Bechstein, Seiler and Schimmel found it to be important enough that they decided to incorporate it recently on their pianos.

I also wrote:

Please note that I respect your opinions, and the opinions of other techs and designers who think the duplexes don’t contribute much or even detract from the performance of the pianos.
However, I disagree with this assessment and believe that duplex scale, definitely including the tunable rear duplex scale can be beneficial. It seems that some of the most respected piano makers in the industry are holding the same opinion.

Posted by Grotriman:
It seems that I should try and stay of this thread as too many people are "dug" in their positions from the other thread...but I'll try to answer your question here.

Please go to your piano and hold the middle C note down so the damper will lift without making a sound. Keep on holding your finger on this note. Now, hit with staccato the C one octave above the C your holding. Do you hear the sympathetic vibe?
Try it now with the F and then the G. Do you hear the C still ringing? I hope that you do.
Now, let the sound die and try to hit the A above middle C while still holding the C...now the A#..the B...the D...

Although there is some sympathetic noise, it is FAR weaker then when hitting the F or G and almost non-existent when compared to the sympathetic tone produced while hitting the higher C.

This is also how the duplex works. First, in order to be effective, the rear duplex have to have a certain length of string that will vibrate and produce a real tone (not just a micro second length of tone). Second, it has to be tuned (or set) to produce a sympathetic sound. Since the rear pressure bar on the Grotrian is not stright, and can't be set to produce a sympathetic sound to allduplex segment strings (as the length of the three strings are different) and since this part is very short and produces only a tone that last milliseconds this isn't a true duplex scale.

Yes, it is a free portion of the string that is not struck, but it is not really sympathetic to the string that is struck.

i decided to also try to pursue grotriman's search for a functional definition of "duplex scale."

in the book produced by steinway, "88 keys, the making of a steinway," here is how they define the term "duplex scale:"

"a design scheme where the ends of the piano's strings are sized so as to vibrate in sympathy with the main portion, resulting in a fuller sound."

by this definition, grotrian has a duplex scale design.

ori, i still do not understand exactly what makes the grotrian design, in your mind, not a duplex? it's not a tunable duplex, but it appears to still be a duplex, using this generic definition.

ori, we cross-posted. i see that you have answered my question with your rationale.

frankly, i really do not set much store by studying any piano's scale design. one cannot deduce from a scale design description if one will fall in love with a piano. play the piano and decide on that basis.

to say that one design is better than another only means something if you've defined the tone and touch you are in search of. which is pretty difficult to do if you are the average consumer.

valid points are being made all around, but i hope the average consumer reading here will not get caught up in thinking that any particular make of piano is better than another for him because of the particulars of the scale design, or whether or not it has a tunable duplex.

play the piano and trust your ears and fingers.

Pique,
In case you were writing this while I posted my last remarks and didn't read the post I made above your...please read it as It may answer your question.

To make it even simpler though, and by using your own supplied definition, duplex is "a design scheme where the ends of the piano's strings are SIZED so as to vibrate in SYMPATHY with the MAIN portion, resulting in a fuller sound."

Well, the relatively short part of the string that is between the bridge and the pressure bar on the Grotrian is not sized to vibrate in sympathy to the main part of the note.

I’ll repeat it a bit more clearly…it is not SIZED to vibrate in SYMPATHY to the MAIN part of the note.

Or maybe I should have written that…it is NOT sized to vibrate in sympathy to the main part of the note.

In any case, by this definition, Grotrian does NOT have a duplex scale design.
It's really quite simple.

As I said in the earlier thread, when I pluck the rear duplex (or whatever one wants to call it) of the Grotrian, the three strings ring out a major third. In other words, if the first one plucked gives a high C, then the second one would be a D and the third one would be an E. This then repeats if I pluck the duplex of the next note up. Everything is lifted a half step up. This regularity suggests (but does not prove) that it is not an accident. Does it have any effect? I really don't know. The piano has wonderful sustain, so a tuneable duplex does not seem to be an absolute necessity for a piano to have a singing sustain.

Pique,
We crossed posts again... :p
You're right though.
What really matter in this regard of the design is if the tone produced is to your liking or not.

Other elements of piano design may influence the way the instruments will hold up and perform in the future, but certainly not this one.
So regarding the duplex scale I agree with you that one has to "play the piano and trust your ears".

This is a true rear duplex scale as used by Steinway and others. Each rear duplex bridge precisely terminates all three strings of a note into a defined length. The system in Grotrian and others does not.
www.tinypic.com/et6reh.jpg

Ori,

Here's a pic of the front duplex on a 290.

BTW, when I made the comment about the rear duplex or whatever is the accurate term for it, I was only speaking of this duplex on my piano; the front, "traditional", as I know it duplex, definitely "sang". The tone on the rear "duplex" lasted just a few micro-seconds.

Derick

Derick, the front duplex on the 280 and 290 is very effective. I bet yours sounds even better in the confines of your living room. The older 213 had a front duplex, I don't know why they did'nt continue it in the new model 214.

I doubt it is the duplex section which is producing the tone. What is happening is that the vibrational energy passes under the capo bar to the speaking length of the string. You won't get much sound if you damp the speaking length.

I suspect that the biggest effect of all these things is changing the impedence of the end points of the speaking length. This would work whether the strings are damped in the duplex section or not.

BDB, the front duplexes on the Bösendorfer are very effective. If you touch your finger to the strings of of a note in the duplex section, then strike the key, the tone is very bland. Remove your finger and strike again, the tone blossoms dramatically.
I'm sure Derick can verify this.

(sorry, wrong forum.)

interesting discussion guys

The following is quoted from something I wrote a few months back. Nothing since then has caused me to change my mind.

From: “Benefit of a duplex or triplex scale design,” 27 May 2005

-----

You might also look at the topic: Duplex Scaling that started 28 July 2004.

Del

As I pointed out before, there are those that don't believe in the benefits of the duplex scale. I guess that this is the reason that certain piano designers decided not to incorporate this part of the design into their pianos. The fact is still, however, that with the exception of those that use single string design to the top of the instrument, the overwhelming majority of tier one and two pianos have some kind of a back duplex scale system and even more use front duplexes whether tunable or not.
The “trend” among modern piano designers seeking to improve the tonal projection and color of their instruments is to use duplexes and they invest much time in engineering systems that will work properly and benefit the piano.

The duplex segment part indeed has to be relatively long (again, as I mentioned before) in order to be effective, and the system has to be designed to perform correctly. Otherwise, some of the criticisms that we hear regarding duplexes can occur.
This may be the reason that in most low-end instruments there are no duplexes, and certainly not tunable duplexes.

Now in theory, as we sometimes here from the critics of the system, duplexes may reduce the sustaining qualities of an instrument...however, complex theoretical explanations aside, does anyone have a real issue with the sustain Mason & Hamlin, Fazioli , Estonia or a C.Bechstein?

Some of the pianos that use tunable duplex scale designs are actually KNOWN for having remarkable sustain....

Again, this isn't a black and white issue. There are those designers that don't like duplexes and are free to design their pianos without them.
They seem to be however in a rapidly growing minority.

The designers of modern instruments, not only from Mason, Fazioli , Estonia and C.Bechstein...but also Seiler, Schimmel Bohemia and Bosendorfer (front ), in addition to many other older designs by Steinway, Yamaha, Kawai and many other makes...
I guess the designers of these instruments weighed the advantages/disadvantages of the system and decided to use duplexes after all.

This isn't a black and white issue, and the ultimate test in this part of design is simply what does one think of the sound.

I’m glad that we have a piano designer on board that is willing to share his theories as to why he decided not to use duplexes on his pianos. I wish though, that the designers of Bosendorfer (front), Fazioli, Mason & Hamlin, Estonia, C.Bechstein and many others would have been writing here too telling us why they decided to use duplexes on their piano and why they believe that a that is properly designed duplex system can benefit the tone in the treble section of the piano.

Ori,
It is a good question why piano makers like Bosendorfer and C.Bechstein and others are now designing pianos using duplex scales. Especially whern there reputations were built on their own unique designs (non duplex). Do they all want to sound more like Steinways?

Rich

I think the reason manufacturers are adding them is that they are cheap for the amount of advertising hype that you can get out of them.