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Krikorick,

This is a very insightful post. I have yet to see any testing even with the very basic equipment RoyP used that shows the Wapin Piano Bridge fails. I've tried myself, but I couldn't make it happen.

Krikorick wrote:

So far I have seen data supporting the claim that the Wapin does affect the piano tone by increasing armonic content and sustain. This difference was captured even with less than optimal instrumentation as mentioned before.

The instrumentation used to determine the change in tone is very important, and it can be electronic or human based. The claims that no change was observed by Wapin were based on human perception. One may argue that that's the ultimate sensor, but I may differ on that opinion and in particular after reading the posts on the safety thread in which it is noted that piano technitians stress their hearing by tuning without hearing protection. How much hearing is lost in those sensors and how much is the remaining sensitivity? It is unknown unless audiometries are performed (or you start asking 3 times for people to repeat you what they say).

I would like to see at this point electronic data showing that a well installed Wapin does not work on some pianos. The instrumentation should be at least as good as the one Roy used to have a fair comparison. After that data is presented and data collection artifacts are dismissed Wapin does what it promises (at least for me).

Usualy discoveries precede their explanation, the more complex the subject the longer the distance between the two.

Regards,
Krikorik

Here are a few more Jazz selections that I feel really show what the Wapin and Isaac Cadenza S hammers did for my piano. I don't have a before/after recording...these are just the 'after'. If you have a pair of headphones, these files sound better than computer speakers.

1. Jazz piano solo played on the LX http://www.box.net/shared/oug27tby2o

2. Jazz piano solo played on the LX http://www.box.net/shared/1oy5qrpgn6

2. Jazz piano solo played on the LX http://www.box.net/shared/amachlxarj

4. Jazz piano solo played on the LX http://www.box.net/shared/nacgrxt30m

5. Jazz piano solo played on the LX
http://www.box.net/shared/2i39evfdyx

6. Jazz piano solo played on the LX
http://www.box.net/shared/6cl6hrdc67

While I appreciate that it is possible to have loose bridge pins on some pianos, this was just not the case on either CC2's or Grandpianoman's pianos. The pins in the before version were tight. Here is another graph I had saved. This is also from CC2's piano, note A5 this time. This is a time series comparison, with the Wapin version on top, the pre-Wapin on the bottom.

I'm wondering whether the side termination works as a kind of pivot for the string. Since the vibrations in the string are primarily up-down, due to the direction of the hammer strike, a termination point on the side of the string almost functions as if you had a little axle running through the middle of the string, allowing it to swing up and down more easily. An angled termination wouldn't allow this.

Roy
Thanks for sharing data which to me is the most efficient way to demonstrate if things work or don't. It would be very interesting to have the same data on a claimed not working case, with some analysis of the geometric and mechanical conditions of the bridge pins pre and post Wapin. String vibrations are sensitive to string boundary conditions as they define displacement and rotation possibilities (and are part of the mathematical solution of the string vibration)
Regards,
Krikorik

Yes, it would. Unfortunately unless the technician doing the actual work takes reasonably accurate measurements and sound records both before and after—and then is willing to share that information even if the results are less than expected—it is unlikely these will ever be available.

Aside from a consistent method of sound recording both before and after, a few photos and some consistent measurements would also be useful.

The sound recording equipment does not have to be elaborate or expensive but it should be some better than the highly variable built-in laptop microphones. My own “travel kit” is fairly simple consisting of an Audix TR 40 measurement microphone and an in-line USB analog-to-digital converter that also supplies phantom power to the microphone. I have a simple, home-made mechanical finger that can be dropped from a measured height to the key to keep the key stroke reasonably consistent. These and a few interconnecting cables are all I need to take a variety of repeatable before and after sound records anywhere in the world. Plus it was all inexpensive enough that I don't worry overly much as it disappears into the checked luggage caves.

I use a mic stand to hold my microphones a measured distance from whatever point I'm measuring when I'm in the shop. In the field I usually enlist the aid of someone standing around watching. I hold the microphone a measured distance from the measurement point (a pre-cut string dropped from the mic down to a marked point on a bridge works well) and have my helper either play the piano or drop the mechanical finger from a pre-determined height onto the test key. Shop measurements are arguably more accurate but the field measurements are reasonably accurate and—as long as I used the same mechanical finger height and hold the microphone in the same location—they are repeatable.

For measurements it would be useful to know something about the bridge pin geometry being replaced.
If I were doing the testing I would be particularly interested in whether or not the strings on one of these pianos had any potential to "pivot" from side-to-side across the leading bridge pin.

I don't know of anyone who has tested for this specifically but it is generally assumed that the amount of bridge pin offset—or the relative lack thereof—does affect string termination efficiency. In other words, a bridge pin arrangement giving a string deflection of, say, two or three degrees will not terminate the string as efficiently as one that deflects the string by eight or ten degrees. I should think this information, by itself, would be useful to the promoter of the Wapin.

By its nature the Wapin arrangement would seem to be less sensitive to the amount of string offset since the string segment just behind the leading bridge pin is effectively trapped. Therefore, intuitively, it would seem likely that the Wapin would have a greater effect of the former than it would on the latter. Intuition is useful only as a starting point. To get meaninful results only careful measurements and testing over a variety of instruments would reveal a statistically reliable answer.

ddf

Krikorik,

You are thinking the same way I did when I invented Wapin. Briefly, I was a technician at the College-Conservatory of Music (CCM), in Cincinnati. I was also pursuing a degree in Mathematics. At part of my degree program I took three semesters of Physics. I had remembered reading an article in Scientific American about 1978. I can't remember the author off hand, but the article proposed a thought model for how the string on a piano vibrates. It suggested that the energy in the string after the hammer strikes it is stored in the string as vibrating components called modes: horizontally (perpendicular to the hammer strike surface) and vertical (in the direction of the strike). The horizontal mode of vibration can viewed as a storage plane since it is parallel to the surface of the board and therefore will not do work on the board and thus use up the stored energy in the string.

So, eager to employ my new learned skills in Physics I had gained through the lab sections of the course, I set out to explore the idea that the slant of the bridge pin might be responsible for increasing the horizontal component of vibration and thus improve sustain. I built a transducer that measured these horizontal and vertical modes in moving piano string. The device put a very small charge on the string of a monochord and the copper plates of the transducer allowed for recording of the change in the electric field over time when the string was in motion. I applied for a grant to build the device and two instrument technicians in the Physics department at the University of Cincinnati built the transducer and figured out how to convert the analog signal to a digital signal. Perhaps I can pull it out of my basement long enough to take a picture of it and post it here on Piano World.

In order test my hypothesis (the slant of the bridge pin contributed to the horizontal component of motion in a string), I had to have a control of some sort. In other words, I needed to test a bridge pin termination configuration where the pin was not slanted but perpendicular to the surface of the bridge. The trouble was that I still needed a clamping function so I placed an additional pin behind the termination pin. The results of experiment showed a difference. But there were a lot of confounding or lurking variables to work out. One was that there was a constant signal noise in the data. It turned out we were measuring fluctuations around a 60 hz signal even though the transducer was applying direct current. I took the instrument back to the instrument techs in the Physics Dept. It sat in their shop until they could get around to figuring out how correct the signal.

In the meantime, I was getting anxious. I knew that there was a difference and I didn't like sitting on my hands until they got around to finding a solution to the instrumentation problem. There was a 1975 Baldwin M sitting in the shop that needed a new block. I keep thinking about this problem. Then I wondered what it would sound like if I used the perpendicular pin on this Baldwin. I modified the killer octave section.... Thus Wapin was invented.

When I got back the monochord transducer. I was able to convince myself of several things. First, no matter what I did, which bridge configuration I used, I was not able to prevent the string from setting up a significant horizontal mode. What I did see is that there was more energy in the string with Wapin. But how much? The experiment portion of Wapin raised more questions than it answered.

One thing became clear to me very early on: that the notion of sustain we toss about as technicians is misleading. Technicians swear they can hear it when the pluck individual strings in the treble and count. If you think about it carefully you will realize that this type of metric will get you no where.

Think of it this way, the brain/auditory system is extremely sensitive and can process information extremely fast especially in the frequency ranges where speech occurs. It takes on the order of a few milliseconds to process auditory information. So an improvement of tonal information of a few more milliseconds will be perceived as having better sustain.

I have a few more recordings that I have not posted with the Wapin Bridge modification and Isaac Cadenza S hammers in place.

The Rachmaninoff, Liszt, and Original Piano Trio recordings are LX selections from the LX Library of Music, which were originally Ampico piano rolls that were transcribed into the native LX language by Wayne Stahnke. On the Rachmaninoff, one can hear this annoying buzzing when the bass energy gets going. I have not been able to find out what it is exactly, yet. Enjoy!

1. The Music of John Williams on the LX http://www.box.net/shared/qr6ju4dzck

2. Liszt on the LX http://www.box.net/shared/rejgxzeth8

3. Rachmaninoff plays Rachmaninoff on the LX http://www.box.net/shared/yhj21em1j3

4. The Original Piano Trio (6 hands) on the LX http://www.box.net/shared/0j3yajus5t

5. The Original Piano Trio (6 hands) on the LX #2 http://www.box.net/shared/7fq6sghn9s

6. Theme from "The Accidental Tourist" by John Williams, on the LX http://www.box.net/shared/eqgyjpmmxa

Del:
Thanks for the description of your setup. I will endeavor to improve my test equipment. I've just been using what I already have. If you have a photo of the mechanical finger you use, I would appreciate it.

Krikorik,

Yes, I would love to see the same type of data on a piano that the "I know a guy who knows a guy who said" have witnessed. I would also like to see this data done by someone who is disinterested. But what we've found is there are aren't people who are disinterested. You have the people who are sold an the Wapin Bridge and the people who have a self interest to protect. We have studies by disinterested parties.

I actually would consider grandpianoman a disinterested party as he really was skeptical from the start. He has only become enthusiastic because of the results. The Wapin Bridge brought out the problems with his hammers (he originally thought the problems were from the Wapin Bridge) Once he installed the Isaac hammers the bridge and the hammers started working together to create the sound he prefers. If you notice his posts he constantly insists the two must go together.

There was a blind test done by over twenty disinterested pianists listening to two new Young Chang PG175s. They were asked to decide which piano was the better of the two after hearing six different students of varying ability perform. The lesser of the two pianos was retrofit with a Wapin Piano Bridge. Two weeks later the same people went through the entire process again. The results switched drastically. The Wapin Bridged piano was overwhelmingly preferred even though it had been easily least desirable two weeks earlier. All the equipment, placement of equipment, and placement of pianos was exactly measured and exactly the same. All the data has been preserved and published. The nay-sayers poo-poo this study because they were Young Changs and students performing. I believe the same type of test was done at a university in Ohio with Baldwin grands, but the Ohio test was done with graduate performers and piano technicians evaluating.

Dr. Stephen Birkett made highspeed (24,000 frames per second) video done before and after a Wapin installation. Unfortunately some piano technicians at the National Piano Technicians Guild Annual Convention decided to sabotage the testing and we were only able to video one string for "after" video. The testing piano was vandalized while supposedly in a secure situation. It says a lot about the lengths some of the nay-sayers are willing to go to stop the Wapin Bridge.

Dr. Robert Coleman did extremely sophisticated testing. Dr. Robert Coleman is an acoustical designer far beyond pianos. Using sound waves to test the space shuttle for problems was his design.

Using a microphone with a mechanical finger is primitive, but if it trips your trigger don't knock it. A mechanical finger is fine with me. I want to see data that supports the Wapin Bridge doesn't work. We have done plenty to support that it does despite the contrary claims.

SpectrumMan, it was me who you quoted and not Krikorik.

It's still packed away following my last trip. I'll try to get it out early next week. Then all I have to do is try to figure out how to post a picture.

ddf

Del, the PW Photo Gallery is the easiest way to upload pictures I have found.

Tim is correct, and I mentioned this fact in a previous post.

My reasoning for posting my experiences with the Wapin and the Isaac hammers were to show what an incredible sound I now have after these 2 changes were made. There was a difference in the piano after the Wapin and before the Isaac hammers. I was not happy with that difference, and was expecting something else. Roy and Randy heard the difference as well.

I suspect that taken as a whole, the cumulative effect of the Wapin on all the strings, which lessens the fundamentals somewhat, and which Roy pointed out in a post above with a graph, that effect was more pronounced by the hard and inflexible Able hammers. As soon as I changed to the Isaac hammer, the new hammers accentuated more of he fundamentals, and at the same time increased some of the upper partials, which is what Wapin seems to be doing by the graphs Roy posted above. The Isaac hammers emphasized these "Wapin" attributes. I now had a more beautiful round and clear tone, with less distortion. The transformation was dramatic, and it has continued to improve as the hammers are played in.

This is what I have heard...it is certainly subjective, but it's true. Perhaps with some new testing as mentioned above, what I have heard and know to be true, can be proven scientifically.

I know what I hear, and I now hear a beautiful, round, rich and clear tone coming from my piano that was not there before the Wapin and the Isaac hammers.

Sorry, I stand corrected.

The graphs are pretty dramatic. If they in fact reflect a true difference created by Wapin, I'm curious where that extra energy is going in the non-wapin configuration; it would have to be lost somewhere. Is it being lost as friction? One would wonder where the friction is.

There is more buried on this topic than what one can read on the posts.



Del
Very clever observations and guidance to help understand the Wapin effect. I'm positive somebody will take to it and share that data in the future.

Michael
It is very inetersting to read the history behind the invention and the experiences of your student years. It will be nice if you can publish as much material as you can of what you did. Remember that in another 100 years of piano history when somebody ask questions about the Wapin, only part of the published data will be available. The more it is published now, the more will reach to them. Good research usually brings a lot of additional questions besides the answers it provides.

Tim
If I follow your post I should consider you an interested party, but I try not disqualify what people say just because it has some interest on something but rather try to form an opinion on the material shared. Once data is reviewed and makes sense it is difficut to deny its validity. Just make the data readily available with as much details of procedures as you can.

Regards
Krikorik

One of the before and after tests which I found most convincing was on our own piano, which at the time was a Samick SG185. My wife is the main player, and she went away for the weekend. Michael Wathen came over and helped with the installation. When we were done, I put everything back the way it was, so she wouldn't know we had worked on it. The first time she sat down to play, she came out and said "the piano sounds better, what did you do?". I was hoping she would notice. She did. Well, that's another kind of test, isn't it?

That's the Wife Test! The most important one.

The "WAF" ...very important!

"Il Postino" on the LX, Wapin Bridge Mod and Isaac Cadenza S hammers in place. http://www.box.net/shared/fav9kacmpv