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Duplex Scale #2739597
05/26/18 08:32 AM
05/26/18 08:32 AM
Joined: Apr 2018
Posts: 81
Indonesia
F
Faiz Offline OP
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Faiz  Offline OP
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Joined: Apr 2018
Posts: 81
Indonesia
Hi, good afternoon (from here hehe)

I just realized that some pianos have their tenor section rear duplex muted with felt, but on some pianos don't, and some has duplex metal bar, but muted as well.
Interesting...

Some picts :
[Linked Image]
Above is a pict of Yamaha G2, it has the tenor duplex open

[Linked Image]
[Linked Image]
On Yamaha C7
But I saw some Yamaha C7 with open tenor duplex as well (I don't have the picture of it)

[Linked Image]
[Linked Image]
[Linked Image]
On Yamaha CF

I am curious what is the purpose of this? What's the difference?
Thanks


(Sorry low quality pictures, it was taken with my phone)


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Re: Duplex Scale [Re: Faiz] #2739610
05/26/18 11:00 AM
05/26/18 11:00 AM
Joined: Sep 2009
Posts: 3,722
Atlanta, GA
PianoWorksATL Offline
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Joined: Sep 2009
Posts: 3,722
Atlanta, GA
Rear duplex scaling is often muted for close to medium distance microphone placement. The frequencies in the tenor can be problematic (recording or not), and muting is an easy solution.


Sam Bennett
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Re: Duplex Scale [Re: Faiz] #2739612
05/26/18 11:15 AM
05/26/18 11:15 AM
Joined: Dec 2012
Posts: 5,118
Seattle, WA USA
E
Ed McMorrow, RPT Offline
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Joined: Dec 2012
Posts: 5,118
Seattle, WA USA
Many of those lowest duplexed hitching lengths are somewhere near the pitch of the top two and a half octaves. They are never and can never be set to pitches that don't create some problems with hearing the upper note clearly to make tuning the piano easier. So some tuners mute them out if they hear a problem when tuning. Even at the factory, thus you see some variation imparted by the final tone regulators.

If you wish to learn more about duplex scales, I have a US Patent called Fully Tempered Duplex Scale that solves the troubles with duplex scales. There is a PW thread of the same name you can see. Duplex scale problems also include issues arising from Longitudinal modes.


In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: Ed@LightHammerpiano.com
Re: Duplex Scale [Re: Faiz] #2739627
05/26/18 12:52 PM
05/26/18 12:52 PM
Joined: Jun 2003
Posts: 27,322
Oakland
B
BDB Offline
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This just demonstrates the lack of efficacy of duplex scaling.


Semipro Tech
Re: Duplex Scale [Re: BDB] #2739646
05/26/18 01:39 PM
05/26/18 01:39 PM
Joined: Dec 2012
Posts: 5,118
Seattle, WA USA
E
Ed McMorrow, RPT Offline
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Joined: Dec 2012
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Seattle, WA USA
BDB, There is no lack of efficacy to the Fully Tempered Duplex Scale. Duplexing maximizes the benefits of pivot termination. Fully Tempering it eliminates the transverse and longitudinal mode noises.


In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: Ed@LightHammerpiano.com
Re: Duplex Scale [Re: Ed McMorrow, RPT] #2739660
05/26/18 02:23 PM
05/26/18 02:23 PM
Joined: Jun 2003
Posts: 27,322
Oakland
B
BDB Offline
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Oakland
I eliminate the transverse, longitudinal, and all other mode noises by not playing the piano. This is something that anyone can easily replicate for themselves, without paying anyone a royalty.

If I do play the piano, I like it to make some noise.


Semipro Tech
Re: Duplex Scale [Re: Faiz] #2739681
05/26/18 04:54 PM
05/26/18 04:54 PM
Joined: Apr 2018
Posts: 81
Indonesia
F
Faiz Offline OP
Full Member
Faiz  Offline OP
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Joined: Apr 2018
Posts: 81
Indonesia
Thanks for the answer guys!

another curiosity, this C7 came from the factory has muted on this section, but they put the metal bar anyway, does that mean we can customize whether we want it open or muted?
[Linked Image]


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Re: Duplex Scale [Re: Faiz] #2739683
05/26/18 05:05 PM
05/26/18 05:05 PM
Joined: Jun 2003
Posts: 27,322
Oakland
B
BDB Offline
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Oakland
If it is your piano, you can do whatever you want. The metal bar is there to establish the height of the strings above the plate. There is clearly no relationship between the length from the bridge to the tips of the plate to either the length or the pitch of the string.


Semipro Tech
Re: Duplex Scale [Re: BDB] #2739687
05/26/18 05:15 PM
05/26/18 05:15 PM
Joined: Apr 2018
Posts: 81
Indonesia
F
Faiz Offline OP
Full Member
Faiz  Offline OP
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Joined: Apr 2018
Posts: 81
Indonesia
ahhh I see
Thanks


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Re: Duplex Scale [Re: Faiz] #2739704
05/26/18 06:56 PM
05/26/18 06:56 PM
Joined: Oct 2012
Posts: 4,032
🎹
Retsacnal Offline

Platinum Supporter until Feb 18  2015
Retsacnal  Offline

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Joined: Oct 2012
Posts: 4,032
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Faiz, in what part of Indonesia do you live?
My wife grew up in Jakarta.


"If it sounds good, it is good." - Duke Ellington
P E R F O R M A N C E over p r o v e n a n c e

Re: Duplex Scale [Re: Faiz] #2739720
05/26/18 08:09 PM
05/26/18 08:09 PM
Joined: Feb 2017
Posts: 2,103
New Hampshire
P
P W Grey Offline
2000 Post Club Member
P W Grey  Offline
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P

Joined: Feb 2017
Posts: 2,103
New Hampshire
Yes, you can mute part or all of it at your discretion.

To test out if you really want to or not, simply use scotch tape or masking tape (TEMPORARILY) TO mute all of it (front and rear), then play the piano and see if you like it better. Then progressively remove the tape and play until you get the sound you really like. Then use thin felt or cloth similar to what the factory used to mute the sections you want.

I do this regularly for people who don't like all the high frequency "noise" they are hearing. DO NOT leave tape on the strings for long as it can leave residue. Repeat: Do not leave the tape on the strings! It is simply a diagnostic procedure...not a cure.

Pwg


Peter W. Grey, RPT
New Hampshire Seacoast
www.seacoastpianodoctor.com
pianodoctor57@gmail.com
https://www.youtube.com/watch?v=PK0T7_I_nV8
Re: Duplex Scale [Re: Retsacnal] #2739762
05/27/18 01:58 AM
05/27/18 01:58 AM
Joined: Apr 2018
Posts: 81
Indonesia
F
Faiz Offline OP
Full Member
Faiz  Offline OP
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Joined: Apr 2018
Posts: 81
Indonesia
Cheers! From Yogyakarta


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Re: Duplex Scale [Re: P W Grey] #2739763
05/27/18 02:04 AM
05/27/18 02:04 AM
Joined: Apr 2018
Posts: 81
Indonesia
F
Faiz Offline OP
Full Member
Faiz  Offline OP
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Joined: Apr 2018
Posts: 81
Indonesia
Thanks for the tip... thumb


Let's help each other... laugh
Re: Duplex Scale [Re: Faiz] #2740051
05/28/18 09:29 AM
05/28/18 09:29 AM
Joined: Sep 2004
Posts: 1,881
Massachusetts
R
Roy123 Offline
1000 Post Club Member
Roy123  Offline
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R

Joined: Sep 2004
Posts: 1,881
Massachusetts
Wouldn't it be fair to say that the main purpose of the metal bars in question is to set the rear down-bearing? Without them, a vertical hitch pin, as is used in some Baldwins, would be required. I also seem to recall Del saying that rear duplexes are essentially worthless. Is my memory correct? Of course, you need some back-scale length to allow the bridge to move, especially in the bass, but, that consideration is unrelated to the idea that a rear duplex could be tuned to some good effect.

Re: Duplex Scale [Re: Faiz] #2740067
05/28/18 10:41 AM
05/28/18 10:41 AM
Joined: Feb 2017
Posts: 2,103
New Hampshire
P
P W Grey Offline
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P W Grey  Offline
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P

Joined: Feb 2017
Posts: 2,103
New Hampshire
In essence I think the duplex system was simply an effort to utilize the otherwise necessary "waste" length of string in such a way as to benefit the sound of the piano. The design on paper certainly makes sense, but in actual manufacturing practice it does not ALWAYS seem to do so. But, it is a seriously good advertising thing at least.

Ed McMorrow has certainly proven that it CAN work, given enough attention.

Unfortunately, it can also contribute to some very difficult tonal issues. And once it is set up and installed at the factory it is very hard to change it (Steinway style anyway). At least we do have the option of muting some or all of it, OR using PitchLock string couplers to modify it in various ways.

Pwg


Peter W. Grey, RPT
New Hampshire Seacoast
www.seacoastpianodoctor.com
pianodoctor57@gmail.com
https://www.youtube.com/watch?v=PK0T7_I_nV8
Re: Duplex Scale [Re: P W Grey] #2740073
05/28/18 11:13 AM
05/28/18 11:13 AM
Joined: Jun 2003
Posts: 27,322
Oakland
B
BDB Offline
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Oakland
There are all sorts of things which are attributed to duplex scales that can be attributed to other things. Claims that they make a difference would not survive a true blind test.


Semipro Tech
Re: Duplex Scale [Re: BDB] #2740114
05/28/18 01:06 PM
05/28/18 01:06 PM
Joined: Sep 2004
Posts: 1,881
Massachusetts
R
Roy123 Offline
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Joined: Sep 2004
Posts: 1,881
Massachusetts
Originally Posted by BDB
There are all sorts of things which are attributed to duplex scales that can be attributed to other things. Claims that they make a difference would not survive a true blind test.


It is also my sense that most of the time, what you say is true.

Re: Duplex Scale [Re: Faiz] #2740122
05/28/18 01:50 PM
05/28/18 01:50 PM
Joined: Mar 2006
Posts: 12,310
Georgia, USA
Rickster Offline
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Georgia, USA
I don't have anything of substance to add to this discussion, other than to say that I've already been down this duplex scale road and done a lot of research on the subject. What I learned was that not all piano manufacturers, even some of the more reputable higher-end, tier-1 makers, use a duplex scale on their grand pianos. I also read that Steinway was among the first makers to use the duplex scale, and many other companies followed their lead, in hopes of copying some of their success, I suppose.

Rick


Piano enthusiast and amateur musician: "Treat others the way you would like to be treated". Yamaha C7. YouTube Channel
Re: Duplex Scale [Re: Faiz] #2740233
05/28/18 11:30 PM
05/28/18 11:30 PM
Joined: Dec 2012
Posts: 5,118
Seattle, WA USA
E
Ed McMorrow, RPT Offline
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Joined: Dec 2012
Posts: 5,118
Seattle, WA USA
The part Steinway got correct in their Duplex Scale Patent of 1872 was the significance of a "pivot" termination. Pivot significance arises because the high stiffness of piano wire allows mode information to move beyond the terminations provided for the normal hammer strike induced transverse modes. This is at the front duplex located between the capo bar and the tuning pin. The rear duplexes, (which is what most people are talking about when they use the term duplex), have far less significance.

What Steinway got incorrect was claiming that the front duplex should be in a whole number relationship with the transverse modes of the speaking length. They also claimed to "harmonize" the longitudinal modes with the transverse. This is not possible.

What I discovered was that some duplex scale noises arise from beats between inaudible, high frequency Longitudinal modes.

Then I devised a way to build a duplex system that apportions the pivot termination effect smoothly across the compass and damps unwanted Longitudinal mode interactions.


In a seemingly infinite universe-infinite human creativity is-seemingly possible.
According to NASA, 93% of the earth like planets possible in the known universe have yet to be formed.
Contact: Ed@LightHammerpiano.com
Re: Duplex Scale [Re: Faiz] #2740241
05/29/18 12:25 AM
05/29/18 12:25 AM
Joined: Mar 2018
Posts: 34
Boston, MA
K
KLX-F1 Offline
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Boston, MA
..and this was the one part of Steinway design that arose directly from correspondence between C.F. Theodore Steinway and Dr. Hermann von Helmholtz, if I remember correctly. Helmholtz wrote a letter afterwards exclaiming the beauty of tone they had finally produced..

I'd like to learn more about your patent, Ed. Very interesting..



Industry professional, registered technician..
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