Piano World Home Page Forums Our Most Popular Forums Piano Forum Hocus-pocus? Is there a better way?

No that is not the challenge at all. The challenge is to demonstrate that it makes an improvement in a double blind test.

Mounting such a test would certainly be a challenge.

With all due respect to every member of this forum, why do we have to subject each claim about piano playing to an FDA testing regime?

It's obvious vanilla ice cream laced with prunes in Armagnac will taste different from vanilla ice cream by itself.

When all the pianists who have played pianos with the isolators say they sound very different (I made enquiries) then a pound to a penny others will too.

The reason it is necessary is that tests have shown that judgement of sound quality is so heavily influenced by expectation and circumstance that a blind, ideally double blind, test actually is necessary to make absolute claims. I must stress this is zero criticism of anyone's judgement, it is just how our perception system works.

In the past I have indulged in expensive hi-fi and, even knowing the above, I have trusted my ears and bought equipment without any sort of blind test. I can do that confidently knowing that if that new bit of kit sounds better to me and I get more enjoyment from it then it is worth it to me, and it doesn't really matter if the improvement is real or imagined, if the increase in enjoyment is there then it is there. But without a valid test that my subconscious cannot influence I can't claim there actually is an improvement far less one that anyone else can hear.

For anyone who is interested in this I always recommend researching a certain Mr. Peter Belt who shows just how much the power of imagination and suggestion can accomplish.

Based upon the video I am still confused:

The piano on the left has a Steinway Logo on the fall board. Does that make it a Steinway?

The piano on the left if it is a Steinway which model?

What is the brand of the Piano on the Right? (I like it better)

Do the isolators work on all models of Steinways: A-D, M,N,O and uprights?

How do you use isolators on a upright?

Will piano isolators make a mediocre piano sound great?

How specific do isolators react with the room? Carpet floors, wood floors marble floors, lots of windows, no drapes, heavy drapes.

Does Steinway endorse this after market product? Will I lose my Steinway guarantee if I install them?

If I buy the isolators, is there a money back guarantee?

I am not convinced about the sound improvement, but the isolators are definitely worth it for bragging rights.

@Panama, quick answers:

The piano on the left has a Steinway Logo on the fall board. Does that make it a Steinway? Stephen Hough is a Steinway artist

The piano on the left if it is a Steinway which model? Don't know.

What is the brand of the Piano on the Right? (I like it better) Don't know.

Do the isolators work on all models of Steinways: A-D, M,N,O and uprights? Yes as could other devices that achieve the same result.

How do you use isolators on a upright? Use four.

Will piano isolators make a mediocre piano sound great? Different.

How specific do isolators react with the room? Carpet floors, wood floors marble floors, lots of windows, no drapes, heavy drapes? They don't as they absorb 97%+ of the vibrational energy trnanitted through the legs.

Does Steinway endorse this after market product? Will I lose my Steinway guarantee if I install them? Of course not (unless Steinway ban the use of third party cups and pads).

If I buy the isolators, is there a money back guarantee? No idea, ask Townshend.

Where in the video is it indicated that these were Mr. Hough's own pianos? I just watched it again, and could not find that.

It does not matter whether they are Stephen Hough's pianos. He appeared familiar with both of them and that is sufficient.

Miss Marple, Agatha Christie's sleuth, was given to saying that when you have a solution to a problem do not look for another.

The most likely scenario is that someone suggested he try the isolators and he said bring them round on Monday at noon, or whenever.

Miss Marple's reasoning device just as easily could be applied to the hypothesis that Mr. Hough was paid to appear on the video, and the whole thing was staged. Because the line of reasoning can support two contradictory explanations, it sheds no light on the matter.

There is nothing in the video to suggest anything was staged, quite the reverse. Why would Mr Hough do such a thing? Miss Marple would not entertain your suggestion for one minute. It is far fetched.

I've heard him play live. He somehow managed to produce a sublime performance despite the handicap of not using the piano isolators.

I don't think any further discussion is going to change our opinions. This is an interesting development, but I prefer a more conclusive demonstration before jumping on the bandwagon. Also, reducing sound reflections from all sources will help a grand or large upright sound better in a small space, which is where the video was made. In a larger space, the effect may not even be audible.

Audio is very tricky. I have had to use the virtual piano technician feature of my digital piano at times to voice it when the weather changes. How can that be? Room effects and the effect of audio room treatments can vary with humidity.

I am very pleased you enjoyed Stephen Hough's performance. You are right, people need to hear a piano or better recordings before deciding whether they prefer clearer piano sounds to the ones they have enjoyed for 150 years or so.

To be fair regarding my earlier remarks I do think my upright sound a bit clearer now that it is placed on simple wood+neoprene cups. If there is actually any difference at all my room is quite likely to show it up as it is a relatively small room (with decent acoustics though) housing a large and loud upright on a suspended wood floor that likes to work as a soundboard extension if given the chance.

However there are so many other things that could be responsible (if there is a difference and it isn't just my perceptions) as the piano is now raised a bit higher from the floor, it is more level due to the cups evening out some floor irregularities, the piano is in a slightly different position to before the cups as, now moving it around is not so easy, I had to decide on a final location and so it is a little further from the wall and no longer exactly parallel to it.


The important thing though is that I actually like, in fact love, how it sounds :-)

It's good to hear you are more than happy with your piano. Long may it continue.

I think there is a bit of a continuum here with the effects of these cups and isolators. I'll have a go at sorting the wheat from the chaff in this thread in a day or two

To recap, this thread is about the discovery that eliminating reverberations from the legs of a grand piano can have a dramatic effect on its sound.

The main evidence for this comes from Mark Swartzentruber, the concert pianist, who found the same transformation with Bosendorfer, Fazioli, Kawai and Steinway pianos. I posted his recording on a Steinway in another thread. Something is awry with the recording itself, you have turn the volume right down for decent sound.


In short, Mark Swartzentruber says the bass and tenor gained transparency while losing their "muddiness" and random distortions. The treble was brighter with more length of tone. Each note had a clearer tone with richer harmonics. He found it easier to hear what he was playing and to control dynamics with more subtlety.

For an explanation of what is going we have to look at the thread on how the frame and case affect the tone of a piano where Ed Foote made this very helpful comment: "The case not only receives, it also delivers, since the entrainment works both ways. If the board is connected to the case and the case vibrates, the board's vibration will be affected by the case vibration".

When the pianist strikes a key the whole instrument vibrates when the hammer hits the strings. At the risk of oversimplification, the strings drive the soundboard while the rest of the energy goes into the frame and the rim. Thus the rim receives the peak energy of the fundamentals and partials and gives back a wide spectrum of lower level sounds. (Reflection and transmission are both going on at the boundary between soundboard and rim).

The complicating factor is the wave energy leaking from the frame into the legs of a grand piano. In wave theory (which is well developed and proven empirically) the castor is a discontinuity or boundary layer between the leg and the floor. Some of the wave energy reaching that boundary is transmitted to the floor and some of it is reflected back into the piano. When these waves get back to the frame they "fight it out" with the waves in the frame. This battle causes who knows what disturbance and distortions. In accordance with "Foote's law" the rim transmits them into the sound board. The result is a piano sound everyone knows and cherishes, like a rich Burgundian wine:


When you take most of the reflections from the castor boundaries away, with an isolator or something, those disturbances and distortions disappear and you can hear the strings much more clearly.

Where you say are the A and B comparisons, the before and after recordings? The best I can offer is a spectral analysis of C2 major chords played on my Ibach grand (without reflections from the castor boundaries) and my Schiedmayer upright (with reflections from the castor boundaries). Previously I'd say their sounds of the same, with the Schiedmater having the edge overall. Now as you can see they are very different, one with clear cut tones, the other blurred.

These charts came from the Spectroid app I downloaded to my Android phone, ever so easy. Why not try it, or an iPhone equivalent, and see what you find.

It would be interesting if venues which give a lot of piano recitals start using isolators and see whether pianists and audiences like the sound better. One problem is that typically, the pianos are rolled into place for the performance and then rolled out for storage, often using a piano dolly that the piano sits on more or less permanently.

I don't think we can judge much/anything from that as the spectral analyses are from two different (actually very different) pianos. Now if you can do the same with/without castor spectral plots on the same piano that would be interesting. I likely don't have enough experience to predict the difference in perceived sound quality from the spectral plots but if there is as significant difference as your two shots above it should be very clear that *something* is happening to the sound.

They are just plots from two pianos as described. That's all really.

That is what Mark Swartzentruber expects to see post Covid. The first ones are likely to be over here.



Quite right.

For the time being, I can only reiterate there is a significant difference in the sound of the piano with the isolators I lashed up. The Spectroid waterfalls are consistent with his comment that pianos tend to be "muddy" in the bass and tenor, that is until you eliminate reflections from the castor boundaries. To interpret the plots, note the C2 major fundamental frequencies are 65-82-98 Hz.

I will make some before and after recordings for both pianos in due course. I need to change the isolators for the grand to something more permanent. As uprights have no legs I will have to test another kind of isolator. The tricky bit will be installing them as the piano is in a confined space and heavy.

As far as the title of this thread goes there is no hocus pocus.