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

Not as crisp or close as I'd like to see, but these pictures of recent Grotrians don't show a tuneable front duplex (no aliquots, only a bearing bar and agraffes; also note the felt under the string section between agraffe and bearing bar):






Nor does this picture of an older model:

Chica,
By these pictures it doesn't look like this is a duplex scale...or what is usually meant when someone is saying “duplex scale”, which is actually a tuned duplex scale...and should actually be called more accurately a tuned aliquot segment as Del pointed out.

But in any case, it doesn't look like what usually people refer to as a duplex scale design, in the spirit of the "duplex scale design" found on certain pianos plates, and definitely isn't a tunable duplex segment (or aliquot segment).

Del,
I'm glad that you didn't take offence to me disagreeing with you, as none was meant and none should be taken.
As I said before, I respect you and understand that you wish to present observations and conclusions you reached to over the years to others.
I have also met though some other piano designers that were happy to share their observations and conclusions with me, and that the results of their experience and knowledge, which was the pianos they designed, left me very impressed.
It just so happens that few of these designers, and obviously some other designers whom I didn't meet with, have an opinion about this matter that is different then yours.
Hence the pianos they design have this element commonly referred to as duplex scale (tuned and tunable aliquot system), and the pianos you design don't have it.

I'm sure these designers, that are also very knowledgeable as you are, also won't lose any sleep at night by knowing that there are skeptics that refuse to accept their observations and conclusions about everything.

I think that this diversity is what makes the instruments offered in the market so interesting and different from each other. If there was only one opinion by one designer that was right all the time, then many of the high end instruments (that are willing to pay for high quality construction of their pianos) would sound just the same.

I for one enjoy this diversity and wouldn't want all pianos to sound like Charles Walters.
I'm happy that in addition to this fine piano there are also Bluthner, Mason & Hamlin, Estonia, Steinway, C.bechstein, Fazioli, Bosendofer and many other makes that can be so different from each other and represent the philosophies of their designers.

I’d like to thank you for your comments though as they are highly appreciated.

Del, I wonder if you'd care to elaborate on this point. Does this phenomenon exist simply because a softer material will almost always preferentially wear when in rubbing contact with a harder material? Is it possible that in wearing a groove in the pressure bar, the string effectively polishes the bar? Does the string, by wearing a groove, soften, or increase the radius of the contact area?

Also, I wonder if anyone has tried any of the sintered metals into which lubricants of various kinds can be imbedded.

Moderators: I wonder if it would be possible to have a button added that would automatically sort the content of threads like this into, say, four seperate columns, labeled:

1. Marketing Terms
2. Technical Equivalents (where there is one)
3. Facts Based on the Physical Sciences
4. Beliefs

This would be most useful, as I find generally find it impossible to reconcile the views and opinions of those who subscribe more to one column or the other, I'd just like to see the sorted text, and try to figure it out myself.
:-)

Del, et. al.,

My Grotrian (whose pictures launched this discussion) is a 2005 model. The front duplex area is not seemingly designed to affect the tone. Unlike the back duplex which clearly sounds when plucked (and in a consistent pattern) the front duplex area is muted.

I guess my background in engineering and science is causing me to discount much of what is being said in this discussion.

There is absolutely no data being presented. Only opinion. This goes for everybody's posting so far.

Theorizing about something does not make it a fact. We know this from the Kansas State School Board.

The Grotrian has a huge angle between the capo bar and the tuning pin plate and the duplex there SINGS LOUDLY. Therefore the energy transmitted is not conducted along the string alone.

To claim that a duplex is "sized" to vibrate with the main note is garbage when it is plain to hear that ALL the duplexes are ringing even if you strike only one note.

To make statements about duplex loudness or sustain intervals without data is merely expressing an opinion. This does not represent a fact.

Numerous other unsupported claims are stated in this discussion and I think we need to examine them one by one.

I am at work and can't take the time (been away on the weekend). But I think we can come up with experiments to verify and validate or prove wrong statements that are being made here. But I do regard a lot of what is being said as opinion and nothing more.

Let's figure out a more intelligent way to pursue this knowledge-quest. Eh?

Ahem.

g,
at this point i am thinking that there are two definitions of "duplex" being bandied about here. there is the literal definition, by which the grotrian scale is obviously a duplex.

and then there is the conventional meaning of the term as it is used in the piano industry, and from this it is less clear to me. it seems our piano industry friends are telling us that by the industry's standard definition of the term, the grotrian does not have a duplex scale design.

further comments, anyone? is my understanding correct:?

I thought this area in a Grotrian was muted with felt. If so, how can is "sing loudly"?

Derick

Thanks. This piano does not have a tuned aliquot stringing scheme. (Therefore it must not have much sustain in the treble sections. Right?) The string deflection angle seems to be (it’s a bit hard to tell from the picture) relatively sharp and short. Through the top two sections there does not appear to be any muting felt. Nor should it ever be necessary.

The backscale will always have a clear sound when plucked and (in a system using a bearing rod such as that shown in the picture) will always have a consistent pattern to it. What any given string backscale segment that is plucked won’t have is a pitch directly related to the speaking length of the string. Except by accident. (Which, come to think of it, pretty much describes most of the so-called tuned duplex—i.e., aliquot—backscales as well.)

Del

well, members of club grotrian, let's not all jump del at once.

del, this piano has amazing sustain. sustain is one of it's most compelling and seductive characteristics.

oh, i almost forgot to post part of the explanation the grotrian factory gave for NOT employing the duplex design.

they said the duplex design was created to lend more power to a low-tension design. the grotrian has thicker strings, i.e., it is a high-tension design, and so the duplex scale is inappropriate for it.

this is from the email they sent me:

I'm not enough of a metallurgist to adequately answer this. It is not appear, however, to be a matter of friction and “wear.”

It is primarily a problem through the upper sections where the hammer blow is relatively close to the string termination—usually a V-bar arrangement of some kind. When the material used for the string termination is as hard, or harder, than the material from which the string is made the string is actually damaged by the repeated blows of the hammer. I suspect the reason for this is that with gray iron—and, to a lesser extent, the various bronzes I mentioned—enough energy is absorbed into the capo tastro bar to take some of the work stress off of the string. But that is just my speculation. What I know for sure is that when the termination material is made hard and the radius is down below about 0.5 mm (assuming the same string diameters, tensions, deflection angles, etc.) treble strings start to break after about half the number of blows that it takes to start breaking their counterparts using a “standard” V-bar shape and material.

Del

It was a joke, piqué, a joke. I know the Grotrian has good sustain.

Del

i see i need to lighten up a bit here. i'll try.

Axtremus said: I play both a Grotrian and a Nordiska on a weekly basis (both new 7-footers). I can tell you that it would take more than removing some felt to make the Nordiska sound like a Grotrian. A whole LOT more!

It’s not all that difficult. The test setup I used when I was looking into this system was a simple monochord with a fixed V-bar and a movable bearing bar/tuning pin block. I could change both the string deflection angle and the duplex string length. I could also move the bridge (along with its rudimentary soundboard assembly) and hitchpin block to accommodate various string lengths, diameters and tensions and work with various backscale configurations.

Have fun....

Del

Hey Pique .... ever heard of deadpan humor?

Alas, it usually soars a few feet over my head too!

Del, I do think the Grotrian has unusual sustain in addition to a particular hollow-sounding tone (in a beautiful way). This is, of course, just a personal impression. Has sustain ever been quantified across brands and holding other things equal?

David F

ummm.... that's humor without the use of graemlins, right?

Del - while you are perhaps the only one here who is equipped to run many of these experiments. You are not providing any data. I know that this is because you are going after what you are hearing.

But a test that is devoid of subjective interpretation includes a measurement technique that everybody can agree on and is independent of interpretation. Like a digitization of the decay envelope of the string with and without a tuned duplex on it so that we can measure the decay of the note. Or a measurement of the acoustic output of the front duplex of a Grotrian (with what I would call a pretty sharp bend up in the string) compared to another piano, using say an electromagnetic pickup similar to a guitar pickup.

These are the types of measurements people need to provide data from in order to make the sweeping generalizations they are making.

I know this has gotten off topic from "what does duplex mean" but I am just a little miffed by all the opinion people are passing off as fact.

So by the way - do you have any "hard" data?

Also I was fortunate enough to have several posts accumulate before I returned to read Del's comment about no treble sustain. It did get my heart racing though...

I'm confused. (As usual.)

Are these duplex and duplex-like thingies activiated by vibrations bleeding from the same string, by vibrations via sound from other strings (different notes), by vibrations via sound from same string, or some combination(s) thereof?

Isn't the Bluthner fourth string activated by sound, presumably by fundamentals and perhaps to a lesser degree by partials?

I thought the Gotrian observation about string tension was interesting, as I'm under the impression that Estonia's string tension is a bit under average, and they have opted for the (allegedly) tunable flavor.

Gotrain is one of my all time favorite pianos, which goes to show that I like both extremes of this design "feature."