For general interest, is anyone able to explain the advantages of setting the hitch pins at the bottom right of this photograph so far back?

Lakeside posted the image last year.

No.

ddf

I think they just thought it looks pretty. Having everything as long as possible going toward the rim probably elongates the look of everything.

Now Del, how can you say that? Obviously, this piano has the longest tenor string for its size over any competitor, which I am sure the marketing department would have used to its advantage . Just forget the fact that it has no function, and is muted to prevent anything audible

Could it have something to do with how stress is applied to the plate?

I think it has more to do with how Steinway strings their longer models. There is a lot of imitation in piano design.

Question for Del:
In that section of the soundboard impedance usually is improved by adding more mass to the bridge therefore the use in certain pianos of an extra-block connecting the treble to the bass bridge.
In theory bringing the hinge-pins closer to the bridge would change the down-bearing of that section therefore a modification would be need it on the treble bridge. If this modification affects the mass of the bridge will affect also the impedance of the soundboard.

Everything being said; here is my question: Is it possible that by keeping the hinge pins at a certain distance a particular down bearing and bridge mass can be achieve that is optimal?

I’m just trying to find a theory that is reasonably objective.

Yes

The hitch pin placement has nothing to do with the downbearing in this case, since that is determined entirely by the height of the string rest and the height of the bridge.

Where is KawaiDon to answer this (I assume he has the answer...)

Inquiring minds await with great anticipation....

ddf

As Dale has pointed out, it’s not a matter of string bearing. This is determined by the relative height of the bridge and the bearing bar.

By nature the bass-to-tenor transition is difficult to blend in overstrung pianos. There are a number of reasons for this and I’m working on a full Journal article on the subject. And that still won’t cover everything.

Yes, some manufacturers do add both stiffness and mass to the end of the tenor bridge by connecting it to the bottom end of the bass bridge. I don’t know if this is done in the Shigeru Kawai or not.

There are other ways of stiffening the end of the tenor bridge and adding effective mass. Many manufacturers are careful to place a rib immediately opposite the end of the bridge. It is also common to extend the length of the tenor bridge somewhat beyond the last set of bridge pins.

The string backscale can have an adverse effect on the mobility of the bridge if it is too short. But this is fairly uncommon; especially on a piano of the length shown at the start of this topic. There is no hard and fast rule for the backscale length but there is a point of diminishing returns. Depending on just where in the scale the bass-to-tenor transition takes place this will be somewhere around 150 to 200 mm. The lower down-scale the bass-to-tenor transition takes place the longer it should be. But even so, making it excessively long does not result in any acoustical advantage.

In my work this only comes up as an issue if a piano exhibits a particular tone disparity across the bass-to-tenor transition and, to my knowledge, this is not a problem with the Shigeru Kawai pianos. I’ve not studied their particular design but I’ve not heard any complaints about this aspect of their performance.

Making the string backscale too short can—and sometimes is—a problem but making it longer than absolutely necessary presents no acoustical problems that I am aware of.

ddf

Would the placement of the hitch pins effect plate stress and tuning stability??

The plate at that point is very wide - it looks like it could be over 20 cm. Moving the hitch pins a few cm in one direction or another will have no impact on bearing, stress, tuning stability or anything else that I can think of, except for the look. Positioning the pins close to (or just back from) the middle of that wide space is probably the most visually acceptable compromise. Not every detail in pianos is deeply rooted in tone or performance!

This hitchpin distance allows a long soundboard with more square meters of surface - with the disadvantage of many kilograms of iron for the frame. A big soundboard may be an advantage. But the advantage would be even bigger if also the strings would be as long as possible within a given chassis/case design.

I checked on a Kawai RX3 grand piano and the hitchpin for the lowest bass note, A, is just 2.5cm from the rim and 1.5cm from the end of the plate.
I have no idea how this compares with other similar pianos, but in relation to the OP, is this just the way they make Kawai grand pianos? My understanding is that the plate and string layout for the Shigeru Kawai pianos are similar to the RX instruments.

Kind regards,

Robert.

I think you'll find we are talking about the plain wire on the right side of the picture, not the bass (wound) strings.

I could not sleep all last night worrying about this.

This is truly one of life's great conundrums and I certainly hope that we can get to the bottom of this soon.

I think we did, and the conclusion was "because it looks cool".

Now you can get some sleep...

This would seem to suggest that the hitch pin location somehow influences or even dictates soundboard size. In fact, it is more the other way around.

It has been posted many times by people who are in the know - Del among others - that this is not the case.

Since the placement is practically arbitrary at that point on the plate, I would observe that moving the hitchpins back makes it easier to string that section of the piano with less interference from the plate struts. It's a small thing, but I can imagine that type of production efficiency tranferring over from the regular Kawai production.

That might be true, but isn't it also just a bit more sexy? It has a certain symmetry with the way the bass strings terminate. There is a certain visual elegance with the narrow x shape formed by similar length strings crossing over each other. I'm surprised more of you don't think visual appeal plays a part in the design of such things.

It does allow me to create a better sounding transition between bass and low tenor.

Initially, something I worked on to improve my understanding of what could be done with the Steinway B break.

With a little creative thinking ..

And it does this how?

ddf

I am curious, this piano looks to have a 26 note bass, 13 unichords ....

What model is this and how long is the piano?

It may be mentioned already, I scanned quickly and didn't see it ... my apologies if I missed it.

Shigeru SK-3,6'1".

Also see LFL's thread for an SK-5, 4th image down(shown below): http://www.pianoworld.com/forum/ubbthreads.php/topics/2009006/SK5%20delivered;%20followup%20from%20o.html#Post2009006



Fewer elongated strings on the SK-5 compared to the SK-3.

They look about the same to me....??? Also, they are from different model years. I can ask the MPA when they come....much later in the year, I suspect.

Bad English, I'm afraid, have replaced "less elongated strings" with "fewer elongated strings". 7 v 5 pairs if I've counted correctly.

Here is an image of a Kawai RX-7 for comparison:

The hitch pin placement has nothing to do with the downbearing in this case

How so ??