Welcome to the Piano World Piano Forums
Over 2 million posts about pianos, digital pianos, and all types of keyboard instruments
Join the World's Largest Community of Piano Lovers (it's free)
It's Fun to Play the Piano ... Please Pass It On!

Gifts and supplies for the musician
SEARCH
the Forums & Piano World

This custom search works much better than the built in one and allows searching older posts.
Ad (Piano Sing)
How to Make Your Piano Sing
(ad) Pearl River
Pearl River Pianos
(ad 125) Sweetwater - Digital Keyboards & Other Gear
Digital Pianos at Sweetwater
(ad) Pianoteq
(ad) P B Guide
Acoustic & Digital Piano Guide
Who's Online
162 registered (accordeur, ajames, A-Tom, Al LaPorte, Almaviva, 45 invisible), 1647 Guests and 19 Spiders online.
Key: Admin, Global Mod, Mod
Quick Links to Useful Piano & Music Resources
Our Classified Ads
Find Piano Professionals-

*Piano Dealers - Piano Stores
*Piano Tuners
*Piano Teachers
*Piano Movers
*Piano Restorations
*Piano Manufacturers
*Organs

Quick Links:
*Advertise On Piano World
*Free Piano Newsletter
*Online Piano Recitals
*Piano Recitals Index
*Piano & Music Accessories
*Music School Listings
* Buying a Piano
*Buying A Acoustic Piano
*Buying a Digital Piano
*Pianos for Sale
*Sell Your Piano
*How Old is My Piano?
*Piano Books
*Piano Art, Pictures, & Posters
*Directory/Site Map
*Contest
*Links
*Virtual Piano
*Music Word Search
*Piano Screen Saver
*Piano Videos
*Virtual Piano Chords
(ad) Estonia Piano
Estonia Pianos
Page 2 of 10 < 1 2 3 4 ... 9 10 >
Topic Options
#2195784 - 12/10/13 09:06 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
rxd Online   happy
1000 Post Club Member

Registered: 03/11/09
Posts: 1806
Loc: London, England
Many intervals exhibit anomalous behaviour. All aural tuners who use all the test intervals in the whole piano must have noticed them, particularly how single octave size and double octave size change places on several notes in and around the top octave, even in the best pianos..
This is maybe the most readily apparent of them, at least it's the first one I ever noticed as an ardent student of all this. It's only about 30 years ago that I started to choose the single octave to tune to instead of the double octave when the alternatives were too noisy in the smaller intervals. That was the time I started working in more recording studios and spending more time listening to playbacks with other musicians than tuning. (1 hour tuning/3hours listening).

Bass strings exhibit even more random exchanges but that's to be expected even in the largest pianos. Far too random to try to marshal them into some sort of order.

ETD's never pick up on them or pick up on the wrong ones.

A wizened old tuner once told me, don't listen too hard, you'll go crazy. Maybe that's what's happnin'.
_________________________
Concert & Recording tuner-tech, London, England.
"in theory, practice and theory are the same thing. In practice, they're not." - Lawrence P. 'Yogi' Berra.

Eschew obfuscation.



Top
(ad PTG 757) The Value of PTG Membership
The Value of a PTG Membership
#2196421 - 12/12/13 05:21 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy
Hi,

Posted in the "Sample" thread:

Originally Posted By: rxd
Originally Posted By: alfredo capurso
Originally Posted By: rxd
Originally Posted By: bkw58
Does the pianist not have at least something to say about it? It's not like he's poking around on an old Underwood. He takes the best that the tuner can provide with what he has to work with and creates his desire with very specific skills at his finger tips.


I must confess to not listening again, I started to but refused to pick through all the talking but the pianist can do much more than we think.

The sustain varies very subtly from note to note in all pianos. A stage piano doesn't always get the maintenance it should and equality of sustain suffers.
while there are ways of poking through the strings with a long needle to obtain more sustain from the hammer, tuning on the day of a big production like this rarely allows for any refinement.

I have to sincerely question isaacs experience of this kind of work. He claims to know but his comments show a distinct lack of understanding. There's more of self promotion in his nit picking criticism. I would expect sympathy with the situation from a real fellow professional. He sounds to me like a really talented amateur who hangs around the profession and then totally falls apart when the real job has to be done. I've known quite a few.


rxd,

I think that only a boor would direct those words to a technician as Isaac, and I do not see how that style can help to describe our work. I think you ought to apologize.
.


I quite agree and understand fully where you're coming from and the emotional content carried over from other threads. - an all too common occurrence.
Since you raised the issue again, It took a few words in order to address an ongoing problem. A totally unfounded, unnecessary and pretentious criticism of a compressed recording couldn't go unchallenged at the same level.

Am I to assume that you agree with isaacs original "criticism" when he himself posted later an admission that he really couldn't tell the difference between what was the piano and what was the tuning and then delete that post a few hours later?

I suggest you read the complete thread. It's all there and doesn't need the deleted parts to be indefensible.

Constructive criticism-Yes.
Self serving, Ill considered boorish and unfounded carping,- a resounding No.


rxd, when you mention "..the emotional content carried over from other threads..", do you mean this thread? Or is it the "How long should it take?", where you wrote:

Originally Posted By: rxd
[/quote]
........ and I think about art.

Best regards, a.c.
.

In all branches of the arts, phrases like this have long been regarded, rightly or wrongly as the last refuge of a charlatan.

I have read some of your work as presented here and experimented with some of it.

You have just another opinion. It is a different twist on an old problem that has been pondered and discussed by generations of fine mainstream tuners who have had to tune the old designs of smaller grands produced by some of the finest makers. Your solution still doesn't address the basic problems.

When I pondered whether or not to dine with you, one of the issues I considered was whether I would be spending a bright convivial evening with a fellow professional or would I be taken hostage by an intense and over enthusiastic amateur. Most people have relationships. Some take others hostage and think it is a relationship.

I asked you directly of your professional experience and you gave me a brief dismissive and evasive answer. I also answered fully to some of your direct technical and artistic questions of me. Your replies to my answers betrayed that you hadn't the feintest idea what I was talking about. It's all in the archives here.

Now you resort to an attempt to insult us all and in the name of art no less.
Ooooooo get you!!.

Let yourself out when you've finished tuning and switch off the lights. We're going to bed.


What I am saying, rxd, is that your insinuations do not help, and in the Sample thread I was not concerned about me, but Isaac.

Sure, I cannot say I am happy to read that I would be a charlatan, or an amateur, or one that would try to take you hostage, or... crazy, as you last wrote in this thread.

Let me suggest: take it easy, be respectful and filter your thoughts and fantasies three times before you post.

About theoretical and practical/technical contents... later on.
.
_________________________
alfredo

Top
#2196424 - 12/12/13 06:00 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
rxd Online   happy
1000 Post Club Member

Registered: 03/11/09
Posts: 1806
Loc: London, England
Sorry, everyone, I appear to have picked up another self obsessed stalker in the above post who, not content with insulting us all and being censured for it, has chosen to mix up the content of two different threads for their own ends.

I apologise to you all for any inconvenience or confusion this has caused.
_________________________
Concert & Recording tuner-tech, London, England.
"in theory, practice and theory are the same thing. In practice, they're not." - Lawrence P. 'Yogi' Berra.

Eschew obfuscation.



Top
#2196425 - 12/12/13 06:27 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy
IMO, there is little to be sorry about, when we try to be clearer.

You confirm your attitude again, rxd. BTW, do you have a name and surname?
_________________________
alfredo

Top
#2196428 - 12/12/13 06:50 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy
Originally Posted By: pinkfloydhomer
I have read the threads about CHAS, and I must admit I don't get it, even if I have a solid mathematical background.

Can someone explain it to me in plain terms? Or at least in mathematically unambiguous terms?

Would it be possible to tune CHAS with TuneLab?


Hi pinkfloydhomer,

Unfortunately I do not know what the user can do with TL, and I am not familiar with recent ETD's; I guess Robert Scott may say, perhaps it is worth a PM?

As for the Chas maths, which is the point you do not get?

Regards, a.c.
.
_________________________
alfredo

Top
#2196430 - 12/12/13 07:11 AM Re: CHAS for Dummies [Re: alfredo capurso]
UnrightTooner Offline
4000 Post Club Member

Registered: 11/13/08
Posts: 4980
Loc: Bradford County, PA
Originally Posted By: alfredo capurso
IMO, there is little to be sorry about, when we try to be clearer.

You confirm your attitude again, rxd. BTW, do you have a name and surname?


No he does not have a real name. He is a robot from a Boy Scout project that went horribly wrong. rxd is just a model number.
_________________________
Jeff Deutschle
Part-Time Tuner
Who taught the first chicken how to peck?

Top
#2196441 - 12/12/13 07:46 AM Re: CHAS for Dummies [Re: rxd]
Tunewerk Offline
Full Member

Registered: 03/26/11
Posts: 425
Loc: Boston, MA
Oh no, he found it..

This thread, even though already resolved, is about to become extremely confusing. And long.

Originally Posted By: Alfredo
Let me suggest: take it easy, be respectful and filter your thoughts and fantasies three times before you post.


This is great advice that you should follow yourself, Alfredo.

Originally Posted By: Alfredo
About theoretical and practical/technical contents... later on.


It always is later on, even if unsolicited. And when you do explain, you never do really explain.

Yes, I think it is clear to everyone that CHAS is more about your own personal show than presenting something of worth.
_________________________
www.tunewerk.com

Unity of tone through applied research.

Top
#2196450 - 12/12/13 08:40 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
rxd Online   happy
1000 Post Club Member

Registered: 03/11/09
Posts: 1806
Loc: London, England
Xd is the original model designation but it all went horribly wrong.
Started to exhibit human traits and developed attitude problems so the R prefix stands for "rebuilt". Now the attitudes are just right.

Some in the piano profession in a few parts of the world know exactly who I am. Some even know who I used to be, still fewer know what I used to be.

Nobody knows why.
_________________________
Concert & Recording tuner-tech, London, England.
"in theory, practice and theory are the same thing. In practice, they're not." - Lawrence P. 'Yogi' Berra.

Eschew obfuscation.



Top
#2196452 - 12/12/13 08:45 AM Re: CHAS for Dummies [Re: rxd]
UnrightTooner Offline
4000 Post Club Member

Registered: 11/13/08
Posts: 4980
Loc: Bradford County, PA
Originally Posted By: rxd
Xd is the original model designation but it all went horribly wrong.
Started to exhibit human traits and developed attitude problems so the R prefix stands for "rebuilt". Now the attitudes are just right.

Some in the piano profession in a few parts of the world know exactly who I am. Some even know who I used to be. still fewer know what I used to be.


And NOBODY, oops, nobody knows what you will become! (Or are you becoming?... naaah)
_________________________
Jeff Deutschle
Part-Time Tuner
Who taught the first chicken how to peck?

Top
#2196454 - 12/12/13 08:48 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
rxd Online   happy
1000 Post Club Member

Registered: 03/11/09
Posts: 1806
Loc: London, England
I am becoming very becoming.

Thanks for a good belly laugh, Jeff

Oh, the original Xd couldn't laugh at itself.
_________________________
Concert & Recording tuner-tech, London, England.
"in theory, practice and theory are the same thing. In practice, they're not." - Lawrence P. 'Yogi' Berra.

Eschew obfuscation.



Top
#2196460 - 12/12/13 09:05 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
Bernhard Stopper Offline
Full Member

Registered: 09/22/08
Posts: 219
Loc: Germany
-
_________________________
Bernhard Stopper
www.piano-stopper.de

Salieri: "Mediocrities everywhere, now and to come: I absolve you all! Amen! Amen! Amen!"
(Amadeus, the movie)

Top
#2196465 - 12/12/13 09:11 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
Phil D Offline
500 Post Club Member

Registered: 01/15/10
Posts: 551
Loc: London, England
Not meaning to be rude, Mr Stopper, but without any knowledge of your own ideas beyond scraps and vague desriptions and the odd video, your ideas are no better communicated than alfredo's, IMO, and both seem to be wrapped very much in self-promotion (although you do actually have a product to sell, which is fine). You just have the good sense not to try and promote it heavily to the members of this board.
_________________________
Phil Dickson
The Cycling Piano Tuner

Top
#2196553 - 12/12/13 01:10 PM Re: CHAS for Dummies [Re: alfredo capurso]
pinkfloydhomer Online   content
Full Member

Registered: 03/07/08
Posts: 377
Originally Posted By: alfredo capurso

Hi pinkfloydhomer,

Unfortunately I do not know what the user can do with TL, and I am not familiar with recent ETD's; I guess Robert Scott may say, perhaps it is worth a PM?

As for the Chas maths, which is the point you do not get?

Regards, a.c.
.


Hi Alfredo, thanks for answering.

What I don't/didn't get about CHAS is/was ... everything smile

I understand the tonal system, I understand various unequal temperaments, I understand equal temperament, I understand the ditonic and the syntonic comma, I understand inharmonicity, I understand what a 6:3 octave is or what a 3:1 twelfth is, I understand what beats are, I understand what equal beating is, I understand what fast and slow beating intervals are, I understand a lot of music theory and I understand the idea behind most aural tuning schemes that I encounter. They all seem to take all of the above into account.

But I didn't understand CHAS since it wasn't precisely described in the threads about it on this forum.

I guess I understand now that CHAS is about equal beating 12ths and 15ths and about a slightly larger semitone ratio than the 12th root of 2? Or is there more to it?

This must be even before we take inharmonicity into account. Taking IH into account, semitone ratio is always greater than the 12th root of 2 on a real piano with positive IH, even if it is tuned in equal temperament. So I guess on a real piano tuned in CHAS, the semitone ratio becomes even greater than the theoretical CHAS semitone because of IH.
_________________________
Piano: Nordiska 120CA upright from 2004.

Top
#2196572 - 12/12/13 02:30 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy
Originally Posted By: pinkfloydhomer
Originally Posted By: alfredo capurso

Hi pinkfloydhomer,

Unfortunately I do not know what the user can do with TL, and I am not familiar with recent ETD's; I guess Robert Scott may say, perhaps it is worth a PM?

As for the Chas maths, which is the point you do not get?

Regards, a.c.
.


Hi Alfredo, thanks for answering.

What I don't/didn't get about CHAS is/was ... everything smile

I understand the tonal system, I understand various unequal temperaments, I understand equal temperament, I understand the ditonic and the syntonic comma, I understand inharmonicity, I understand what a 6:3 octave is or what a 3:1 twelfth is, I understand what beats are, I understand what equal beating is, I understand what fast and slow beating intervals are, I understand a lot of music theory and I understand the idea behind most aural tuning schemes that I encounter. They all seem to take all of the above into account.

But I didn't understand CHAS since it wasn't precisely described in the threads about it on this forum.

I guess I understand now that CHAS is about equal beating 12ths and 15ths and about a slightly larger semitone ratio than the 12th root of 2? Or is there more to it?

This must be even before we take inharmonicity into account. Taking IH into account, semitone ratio is always greater than the 12th root of 2 on a real piano with positive IH, even if it is tuned in equal temperament. So I guess on a real piano tuned in CHAS, the semitone ratio becomes even greater than the theoretical CHAS semitone because of IH.


Hi pinkfloydhomer,

It is as you say, Chas semitone ratio is slightly larger than the 12th root of 2.

Also the rest is correct: "This must be even before we take inharmonicity into account. Taking IH into account, semitone ratio is always greater than the 12th root of 2 on a real piano with positive IH, even if it is tuned in equal temperament. So I guess on a real piano tuned in CHAS, the semitone ratio becomes even greater than the theoretical CHAS semitone because of IH."

In Chas equation (3-delta)^(1/19)= (4+s*delta)^(1/24)

12ths and 15ths deviate from 3:1 and 4:1 depending on the parameter "s";

for s=1 12ths and 15ths deviate by the same (delta) amount.

That's all.

Cheers, a.c.
.
_________________________
alfredo

Top
#2196629 - 12/12/13 04:47 PM Re: CHAS for Dummies [Re: alfredo capurso]
pinkfloydhomer Online   content
Full Member

Registered: 03/07/08
Posts: 377
Okay then, but can you explain to me in short, precise terms why the CHAS semitone ratio is desirable and better than other suggestions (most notable 12th root of 2), and also why equal beating 12ths and 15ths are better than other approaches?

Why isn't CHAS just one more random way to tune? Why is it special? What sets it apart? It must have some kind of fundamental idea binding it together. And idea that it must be possible to express in short and precise terms to an educated audience. An executive summary.
_________________________
Piano: Nordiska 120CA upright from 2004.

Top
#2196640 - 12/12/13 05:09 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
Withindale Offline
2000 Post Club Member

Registered: 02/09/11
Posts: 2089
Loc: Suffolk, England
Originally Posted By: pinkfloydhomer
I have read the threads about CHAS, and I must admit I don't get it, even if I have a solid mathematical background.

Can someone explain it to me in plain terms? Or at least in mathematically unambiguous terms?

Would it be possible to tune CHAS with TuneLab?

Going back to your original question, PFH, this thread and the one about Stopper's temperament have shown that it's not possible to tune CHAS with Tunelab.

CHAS is a heuristic method of tuning rather than a deterministic one with offsets you can feed into an ETD.

Alfredo has set out the method in some detail (see this English translation) and explained that he allows for "variable stretch" in his tunings (see his post in the Stopper thread yesterday).

As I see it, you will never know in advance what the values of his "s" variables will be. To achieve the beat rate progression curves he is looking for stretch may swing between pure octaves and pure twelfths; conceivably more I suppose.

No doubt you are familiar with those Railsback diagrams with smooth curves approximating inharmonicity and jagged lines showing actual tunings. A Railsback curve represents a mathematical model which is a figment of the imagination. The jagged line is reality.

Don't get me wrong, I am a great believer in mathematical models. They can do a lot, but I know their limitations.

You will never get CHAS from Alfredo's equations, nor will anyone else. It's the tunings that matter.
_________________________
Ian Russell
Schiedmayer & Soehne, 1925 Model 14, 55" upright
Ibach, 1922 49" upright (project piano)

Top
#2196643 - 12/12/13 05:23 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
Tunewerk Offline
Full Member

Registered: 03/26/11
Posts: 425
Loc: Boston, MA
This it does not have.

It does not have this because CHAS is a retroactive arithmetical explanation for subjective, qualitative field experience that has led a lot of tuners to believe tuning near the 12th works best on the modern piano.

It works backwards, not forwards. It provides a gum-and-tape explanation for complex interactions. As a result of this, it cannot be used as a model to work forward or predict anything physical in terms of real pianos.

Not only that, but the mathematical model is insufficient and incorrect. It does not model what Alfredo claims it does. I've modelled this in MatLab some time ago.

The positive role this model could have is giving new tuners a more quantitative view for the goal of tuning. Used in general conceptual terms, it could be helpful.

Originally Posted By: Withindale
CHAS is a heuristic method of tuning rather than a deterministic one with offsets you can feed into an ETD.

Alfredo has set out the method in some detail (see this English translation) and explained that he allows for "variable stretch" in his tunings (see his post in the Stopper thread yesterday).

As I see it, you will never know in advance what the values of his "s" variables will be. To achieve the beat rate progression curves he is looking for stretch may swing between pure octaves and pure twelfths; conceivably more I suppose.

No doubt you are familiar with those Railsback diagrams with smooth curves approximating inharmonicity and jagged lines showing actual tunings. A Railsback curve represents a mathematical model which is a figment of the imagination. The jagged line is reality.

Don't get me wrong, I am a great believer in mathematical models. They can do a lot, but I know their limitations.

You will never get CHAS from Alfredo's equations, nor will anyone else. It's the tunings that matter.


+1


Edited by Tunewerk (12/12/13 05:33 PM)
_________________________
www.tunewerk.com

Unity of tone through applied research.

Top
#2197209 - 12/13/13 07:09 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy
Originally Posted By: pinkfloydhomer
Okay then, but can you explain to me in short, precise terms why the CHAS semitone ratio is desirable and better than other suggestions (most notable 12th root of 2), and also why equal beating 12ths and 15ths are better than other approaches?

Why isn't CHAS just one more random way to tune? Why is it special? What sets it apart? It must have some kind of fundamental idea binding it together. And idea that it must be possible to express in short and precise terms to an educated audience. An executive summary.


Hi pinkfloydhomer,

Yes, I can try, but at some point we will have to address theory and practice separately, so that we do not get confused.

@ ...why the CHAS semitone ratio is desirable...

Here I can only talk subjectively, I was longing for a ratio (and tuning criteria) that my sense_of_intonation could justify, and that ratio was lacking. That “desire” made me start with my research... on the one hand there was no way to tune pure octaves, on the other hand there was no need to avoid faintly beating octaves... This made me believe that perhaps a better scale_geometry could be found, that it could depend on strict application.

@ ...and better than other suggestions (most notable 12th root of 2)...

There is no way we can put 12th root of two into practice; that ratio favors pure_octaves (2:1), and in doing so it doubles all other intervals deviation values, every other octave; the Chas semitone ratio is “better” in that it spreads deviations amongst all intervals, so that - octave after octave - all intervals can progress together, as part of a whole.

@ ...why equal beating 12ths and 15ths are better than other approaches?...

12ths and 15ths..., because in this way we actually stretch the fourth (4:3 - in between the 12th and the 15th) which is the interval that first closes a circle (we say so, but it is a spiral), enumerating the number (4*3) of semitones.

@ ...Why isn't CHAS just one more random way to tune?...

The Chas model has nothing against “random” tunings, i.e. tunings that may result from any other semitone ratio, that is the meaning of the “s” variable; in fact, this is a fundamental passage: we are expected (and enabled) to modify the ratio in order to set the “desired” semitone progression; on the other hand, s=1 defines the most coherent geometry.

@ ...Why is it special?...

The Chas ratio (with s=1) is special in that it is self-referential: by stretching the fourth (4:3), we determine the constraint for 12ths (3:1) and 15ths (4:1), and s=1 fixes that constraint in 1:1 proportion.

@ ...What sets it apart?

Maximum coherence.

@ ...It must have some kind of fundamental idea binding it together...

No interval needs to be pure;

Deviations define “color”, more than pure intervals;

Deviations need to be ordered in proportion;

We can order scale frequencies and deviations with one ratio;

What we need to consider, represent and aim at, it's a dynamic (beating) whole, then we can set the premises.

@ ...And idea that it must be possible to express in short and precise terms to an educated audience. An executive summary.

I do make use of a PowerPoint with some short phrases and graphs... are you asking for that?

Regards, a.c.
.
_________________________
alfredo

Top
#2208734 - 01/05/14 03:11 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
alfredo capurso Offline
1000 Post Club Member

Registered: 07/10/07
Posts: 1085
Loc: Sicily - Italy

Hi,

Phil, it is a bit of a shame that my sharings on this board appears as self-promotion, as if I wanted to sell something... Honestly, I do not understand what is giving this impression, if not my mere enthusiasm when I think that, three hundred years ago, these results would have remained the preserve of a few. Anyway, thank you for posting and for pointing that out (and thanks PW for providing this opportunity).

Tunewerk, I hope you will be able to compare the Chas model with other models and soon realize that the tonal scale is now tailored correctly. About maths, try not to confuse notions, for instance what “equality” means, and about tuning in general, try to help other colleagues understand now why the octave needs to be stretched. Oh, it would be great if you could help also Jeff, Chris, Kees and Bill.. :-)

Here is a link to some literature:
http://www.huygens-fokker.org/docs/bibliography.html#C

Ian, thank you for your posts... seeing how other posters mix up notions, concepts and practical issues, I find your lines refreshing.

To All, have a nice Epiphany.
.
_________________________
alfredo

Top
#2273227 - 05/09/14 11:55 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
Kent Swafford Offline
Full Member

Registered: 06/06/07
Posts: 81
Loc: Kansas City
In keeping with this topic for dummies, I would like to present an imitation CHAS -- for dummies like me.

This is an equal temperament very close to that of CHAS, but one that I will describe in terms with which I am familiar. I am hoping others will see this as a worthy contribution to the topic.

First, mathematical models are useful, in that they identify the target beat rates from which you will depart when actually tuning in the real world. A piano tuned to a 12th root of 2 model will have beat rates as close as possible to that of the 12th root of 2 model.

Pianos are scaled in general so that their beat rates can approach that of the models of equal temperament; this is obviously less true for some pianos than it is for others, but it would have been easy to make pianos that could not be tuned with beat rates that remotely resemble the beat rates of any model.

Modern equal temperaments come in a variety of widths.

The temperament denoted by the 12th root of 2 is 12-tone to the just octave equal temperament. It is characterized by clean octaves, and with 4ths expanded by approximately 2 cents and 5ths contracted by the same approximate 2 cents. The C4-F4 fourth will beat the same as the F4-C5 5th. (If that 4th is faster than that 5th, then the octave is expanded, and the model for the tuning is not the 12th root of 2.) This is considered to be the most narrow equal temperament that is musically useful.

The temperament denoted by the 7th root of 1.5 is 7-tone to the just fifth equal temperament. It is characterized by clean fifths -- and octaves expanded by approximately 3 1/3 cents. The C3-A3 sixth will beat the same as the C3-E4 10th. This is sometimes considered to be the widest equal temperament that is musically useful. However, my PTG Atlanta institute class will demonstrate some equal temperaments that are substantially wider than this.

The temperament denoted by the 19th root of 3 strikes a middle ground in the range of equal temperaments. It is characterized by clean 12ths — and by octaves expanded by approximately 1 1/4 cents and 5ths contracted by the same approximate 1 1/4 cents. The D3-A3 5th will beat the same as the A3-A4 octave. If this temperament is executed evenly across a piano scale, some, including myself, claim that a particularly coherent tuning will result.

The source of the coherence of a tuning with an evenly-executed stretch may be the temperament itself, or perhaps it is that it is unusual for a chosen specific level of stretch to be accurately executed across a whole scale. This appears to still be an open question, because it seems to be reasonable to think that executing a consistent amount of stretch across a scale might contribute to coherence in a tuning. My class will deal extensively with these and related issues.

There are other widths of equal temperament that can be readily identified, including one denoted by the 31st root of 6. It is characterized by clean double-octave 5ths. The C3-C4 octave will beat the same as the C4-G5 12th.

Of particular interest to this PianoWorld topic is the equal temperament denoted by the 43rd root of 12. It is characterized (at least theoretically, in its zero-inharmonicity mathematical form) by clean triple-octave 5ths, and double octaves that are expanded by the same amount in cents (about 1.09 cents) as the 12ths are contracted (again, about 1.09 cents). The C3-G4 12th will beat the same as the G4-G6 double-octave. (I believe equal-beating double octaves and 12ths are claimed in CHAS.)

It would be of interest to me to understand how the 43rd root of 12 ET differs substantially from CHAS. They appear to be so similar that it would be difficult to aurally distinguish one from the other. Perhaps someone could identify for me a specific pair of 12th and double-octave that would be equal-beating in CHAS.?

Thanks.

Top
#2273276 - 05/09/14 02:14 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
UnrightTooner Offline
4000 Post Club Member

Registered: 11/13/08
Posts: 4980
Loc: Bradford County, PA
Mr. Swafford:

I rarely view posts having to do with CHAS, but I made an exception when seeing that you posted to this Topic.

The purpose of CHAS is for Alfredo to promote himself. The model is for 12ths and double octaves with a common note on top bottom to beat at the same speed. This is virtually identical to "mindless octaves". So D3-A4 A2-E3 would beat (3:1 narrow of just intonation) the same as A2-A4 (4:1 wide of just intonation).

I believe pure 12ths to be an exceptional stretch and use it exclusively. I don't want to post about it on this Topic, but here is a current one on the subject: P12 Tuning Sequence

If you respond, I may not get back to you until Monday. I rarely post on weekends.


Edited by UnrightTooner (05/09/14 05:07 PM)
Edit Reason: correct error
_________________________
Jeff Deutschle
Part-Time Tuner
Who taught the first chicken how to peck?

Top
#2273361 - 05/09/14 05:48 PM Re: CHAS for Dummies [Re: Kent Swafford]
Mark R. Offline
2000 Post Club Member

Registered: 07/31/09
Posts: 2069
Loc: Pretoria, South Africa
Dear Kent,

You start of by writing:

Originally Posted By: Kent Swafford
In keeping with this topic for dummies, I would like to present an imitation CHAS -- for dummies like me.

This is an equal temperament very close to that of CHAS, but one that I will describe in terms with which I am familiar. I am hoping others will see this as a worthy contribution to the topic.


You then proceed to present various degrees of stretches:

Originally Posted By: Kent Swafford
The temperament denoted by the 12th root of 2

[...]

The temperament denoted by the 7th root of 1.5

[...]

The temperament denoted by the 19th root of 3

[...]

it seems to be reasonable to think that executing a consistent amount of stretch across a scale might contribute to coherence in a tuning.

[...]

There are other widths of equal temperament that can be readily identified, including one denoted by the 31st root of 6.

[...]

Of particular interest to this PianoWorld topic is the equal temperament denoted by the 43rd root of 12.


May I ask: which of these schemes (or widths) is it that you would like to "present as an imitation CHAS"?
_________________________
Autodidact interested in piano technology.
LinkedIn profile
1922 49" Zimmermann, project piano.
1970 44" Ibach, daily music maker.

Top
#2273601 - 05/10/14 10:49 AM Re: CHAS for Dummies [Re: pinkfloydhomer]
Olek Offline
7000 Post Club Member

Registered: 03/14/08
Posts: 7904
Loc: France
In Chas temperament method there is an unique feature that I never find anywhere , that is the installation of future enlarging that is done in an initial not particularely expanded octave (minimally expanded, in my opinion, when comparing with some basic octaves A3 A4 I have seen describe.)

Without that trick you cannot tune with higher ratios than 2:1 without raising a lot the speed of FBI and even the octaves and doubles.

In my opinion





Edited by Olek (05/10/14 10:50 AM)
_________________________
It is critical that you call your Senators and Representatives and ask them to cosponsor S. 2587 and H.R. 5052. Getting your legislators to cosponsor these bills


Top
#2273716 - 05/10/14 04:09 PM Re: CHAS for Dummies [Re: Kent Swafford]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1766
Loc: Vancouver, Canada
Originally Posted By: Kent Swafford

There are other widths of equal temperament that can be readily identified, including one denoted by the 31st root of 6.

And there is the 55th root of 24, the 61st root of 34, the 67th root of 48, the 74th root of 72, the 79th root of 96, etc. etc. ad infinitum.

These theoretical numbers (relevant to a theoretical zero inharmonicity instrument) differ by such small amounts that these differences are completely washed away by effects caused by inharmonicity in a real piano.

Kees

Top
#2273755 - 05/10/14 06:08 PM Re: CHAS for Dummies [Re: DoelKees]
Kent Swafford Offline
Full Member

Registered: 06/06/07
Posts: 81
Loc: Kansas City
Kees writes:

"These theoretical numbers (relevant to a theoretical zero inharmonicity instrument) differ by such small amounts that these differences are completely washed away by effects caused by inharmonicity in a real piano."

Of course.

But _my_ point remains that there are various widths of equal temperament that _are_ readily identifiable by their characteristic beat rate patterns, as I detailed. These various ET's can be aurally differentiated from each other.

The ET denoted by the 43rd root of 12 would, I believe, be difficult to aurally distinguish from CHAS.

Since the 43rd root of 12 ET is easily described and CHAS is somewhat difficult to describe, I suggest that the 43rd root of 12 ET might be a good simpler alternative to CHAS.

Top
#2273800 - 05/10/14 10:24 PM Re: CHAS for Dummies [Re: pinkfloydhomer]
Chris Leslie Online   content
500 Post Club Member

Registered: 01/01/11
Posts: 756
Loc: Canberra, ACT, Australia
Kent, Just a few figures:

If A6 on a typical Yamaha U1 is tuned we get about 1776 or so Hz using a reasonable stretch.

With 12 root 2 the frequency is 1760 Hz
With 19 root 3 the frequency is 1762 Hz
With 7 root 1.5 the frequency is 1767 Hz
With 42 root 12 the frequency is 1820 Hz

Although I have only shown one note, none of these models resembles what a real piano should be given inharmonicity. A particular model may be close for some parts of the scale and some pianos but not others. I think it is pointless trying to characterise CHAS with a model such as these unless it is modified with other coefficients such as what Alfredo does.

12 root 2 is a default model and is fundamental reference for the way we describe tuning systems. It is not used in practice for pianos unless we describe tuning frequencies in terms of cents offsets from 12 root 2. With the other models we will still have to describe actual tuning frequencies in terms of deviations from the theoretical values of the model.


Edited by Chris Leslie (05/10/14 10:42 PM)
_________________________
Chris Leslie
Piano technician
http://www.chrisleslie.com.au

Top
#2273865 - 05/11/14 06:24 AM Re: CHAS for Dummies [Re: Chris Leslie]
Kent Swafford Offline
Full Member

Registered: 06/06/07
Posts: 81
Loc: Kansas City
Originally Posted By: Chris Leslie
Kent, Just a few figures:

If A6 on a typical Yamaha U1 is tuned we get about 1776 or so Hz using a reasonable stretch.

With 12 root 2 the frequency is 1760 Hz
With 19 root 3 the frequency is 1762 Hz
With 7 root 1.5 the frequency is 1767 Hz
With 42 root 12 the frequency is 1820 Hz

Although I have only shown one note, none of these models resembles what a real piano should be given inharmonicity. A particular model may be close for some parts of the scale and some pianos but not others. I think it is pointless trying to characterise CHAS with a model such as these unless it is modified with other coefficients such as what Alfredo does.

12 root 2 is a default model and is fundamental reference for the way we describe tuning systems. It is not used in practice for pianos unless we describe tuning frequencies in terms of cents offsets from 12 root 2. With the other models we will still have to describe actual tuning frequencies in terms of deviations from the theoretical values of the model.


The value I get for A6 using the 43rd root of 12 is more like 1761.11.

Models assume zero inharmonicity, so there is obviously no claim that they "resemble what a real piano should be given inharmonicity".

You use the phrase, "we describe tuning frequencies in terms of cents offsets from 12 root 2". Yes, that is the way models are used in electronic tuning devices.

However, there is another way to use models, as I pointed out in my post. As Daniel Levitan puts it in his text, The Craft of Piano Tuning: "...Piano tuners always prefer to approximate to some extent the theoretical beat rates of equal temperament, purposefully mistuning 1st partials... This is because piano tuners listen, not to 1st partials, but to coincident partials. Through the artful mistuning of 1st partials, tuners strive to create the illusion that there is no inharmonicity in the intervals of a piano."

So, as I said, models provide target beat rates, not frequencies.

Top
#2274033 - 05/11/14 01:46 PM Re: CHAS for Dummies [Re: Kent Swafford]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1766
Loc: Vancouver, Canada
Originally Posted By: Kent Swafford

So, as I said, models provide target beat rates, not frequencies.

Any reasonable model of piano tuning should incorporate a model of inharmonicity, as do all ETD's.

2^(1/12) model is the coarsest model and gives you ballpark figures for beatrates. Any refinement of this model should first deal with inharmonicity, then the various stretching methods can be discussed.

Fooling around with other semitone ratios without modeling inharmonicity seems pointless to me. You can propose any real number close to 2^(1/12) as the basis of a "new tuning", it does not matter if it can be written as the foo root of bar or not.

That's why the whole chas "theory" is pointless.

Kees

Top
#2274055 - 05/11/14 02:34 PM Re: CHAS for Dummies [Re: DoelKees]
Kent Swafford Offline
Full Member

Registered: 06/06/07
Posts: 81
Loc: Kansas City
Originally Posted By: DoelKees
Originally Posted By: Kent Swafford

So, as I said, models provide target beat rates, not frequencies.

Any reasonable model of piano tuning should incorporate a model of inharmonicity, as do all ETD's.

2^(1/12) model is the coarsest model and gives you ballpark figures for beatrates. Any refinement of this model should first deal with inharmonicity, then the various stretching methods can be discussed.

Fooling around with other semitone ratios without modeling inharmonicity seems pointless to me. You can propose any real number close to 2^(1/12) as the basis of a "new tuning", it does not matter if it can be written as the foo root of bar or not.

That's why the whole chas "theory" is pointless.

Kees


<grin>

There is a way of tuning in which one can pick a stretch level by choosing a width of equal temperament and using the beat rates of that width of ET to provide the target beat rates for a tuning, regardless of inharmonicity.

The chosen width and its associated beat rates are executed across a scale artfully by the piano tech to provide a best-fit, coherent tuning in spite of inharmonicity.

Top
#2274064 - 05/11/14 02:54 PM Re: CHAS for Dummies [Re: Kent Swafford]
DoelKees Offline
1000 Post Club Member

Registered: 05/01/10
Posts: 1766
Loc: Vancouver, Canada
Originally Posted By: Kent Swafford

There is a way of tuning in which one can pick a stretch level by choosing a width of equal temperament and using the beat rates of that width of ET to provide the target beat rates for a tuning, regardless of inharmonicity.


I don't see how that is possible. Let's take a semitone of 2^(1/12) and try to use those zero-ih beatrates as guides.

The octaves (and double, and triple, etc) have theoretical beatrates of zero. Problem is that on a real piano a single octave has at least 3 beat rates, 2:1, 4:2, and 6:3, which can not all be zero. What do you now do with your "target beat rate"?

Kees

Top
Page 2 of 10 < 1 2 3 4 ... 9 10 >

Moderator:  Piano World 
What's Hot!!
Christmas Header
- > Gift Ideas for Music Lovers < -
From PianoSupplies.com a division of Piano World.
-------------------
The December Free Piano Newsletter
-------------------
Forums Rules & Help
-------------------
ADVERTISE
on Piano World

The world's most popular piano web site.
-------------------
PIANO BOOKS
Interesting books about the piano, pianists, piano history, biographies, memoirs and more!
(ad) Yamaha CP Music Rest Promo
Yamaha CP Music Rest Promo
(ad) HAILUN Pianos
Hailun Pianos - Click for More
Ad (Seiler/Knabe)
Knabe Pianos
(125ad) Dampp Chaser
Dampp Chaser Piano Life Saver
(ad) Lindeblad Piano
Lindeblad Piano Restoration
(ad) Piano Music Sale - Dover Publications
Piano Music Sale
Sheet Music Plus (125)
Sheet Music Plus Featured Sale
New Topics - Multiple Forums
why do I suddenly have clacking bass notes
by music32
8 minutes 10 seconds ago
Kawai Digital Piano
by Deegs23
Today at 03:28 PM
A new clip of the great Don Pullen in action
by rintincop
Today at 01:41 PM
A new clip of the great Don Pullen in action
by rintincop
Today at 01:38 PM
Digital piano Actions MP11,RD-800,CP4
by oliver123456
Today at 01:26 PM
Forum Stats
77340 Members
42 Forums
159959 Topics
2349136 Posts

Max Online: 15252 @ 03/21/10 11:39 PM
Gift Ideas for Music Lovers!
Find the Perfect Gift for the Music Lovers on your List!
Visit our online store today.

Visit our online store for gifts for music lovers

 
Help keep the forums up and running with a donation, any amount is appreciated!
Or by becoming a Subscribing member! Thank-you.
Donate   Subscribe
 
Our Piano Related Classified Ads
|
Dealers | Tuners | Lessons | Movers | Restorations | Pianos For Sale | Sell Your Piano |

Advertise on Piano World
| Subscribe | Piano World | PianoSupplies.com | Advertise on Piano World | Donate | Link to Us | Classifieds |
| |Contact | Privacy | Legal | About Us | Site Map | Free Newsletter | Press Room |


copyright 1997 - 2014 Piano World ® all rights reserved
No part of this site may be reproduced without prior written permission