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We’d need to hear a before and after on the same piano, with good mics, and with nothing done to the piano between tests except for the isolators. Both videos have relatively low quality audio and no real point of reference—further, in Hough’s video the mic position effectively changed between pianos since the second piano was in a different place and as a result the room acoustics will be different as well.

That’s not to say there isn’t a difference. Years ago Estonia made a point of saying their keybeds don’t protrude below the rim and said this had a beneficial tonal effect (or something like that). Certain things have an effect, but it’s more about differentiating piano brands and designs rather than definitively being ‘better’.

I suspect another issue would be what the floor material is made of. If it’s wood then you’ll get more reflections and resonating vs. castor cups over a thick carpet—kind of like subwoofer issues on home audio equipment. Though perhaps someone could argue that pianos can benefit from it.

In any case, interesting thought.

That's a good idea I will suggest it when I have the opportunity.

Wow! The purpose of this thread is to share what I found and ask whether anyone is doing something similar.

Steingraeber and Phoenix have decided acoustic isolation is a good thing. I agree, as those 12 balance rail punchings greatly improved the sound of my Ibach.

As it happens the Ibach's tonal signature now has similarities with the two Steingraeber Phoenix pianos I tried, one with a spruce soundboard, the other carbon fibre. Maybe that's not so surprising when you remember Ibach and Steingraeber were birds of a feather 120 years ago.

It wasn't so long ago that it was being claimed that coupling the piano legs more solidly to the stage produced a better sound, and getting rid of the spider dollies was the best practice...

Ron Koval

IMO, Stephen Hough playing some harsh chord, arpeggios, is just making a fine irony of the somewhat weird situation. He is sure a fine gentlemen.

No, it's real -- although I'm not quite sure why one would want to reduce tonal output...

The Appleton Chapter of PTG conducted tests on a Baldwin SD-10 with direct contact to the floor of the stage and supported on a stage truck (spider trolley) and listeners in the seats could notice the difference as well as the pianist.
Interestingly, the pianists also noticed an improvement in touch when the piano was directly in contact with the floor.

(For our experiment, the piano was mounted on a trolley but machinist jacks were installed between the caster cups and the floor to provide a direct mechanical connection).

This is one reason why performance venues use transporters to move their performance instruments onto/off stage -- so that the additional vibrational energy that travels down through the legs (maybe 10% of total sound output -- not all of it comes off the soundboard into the air) can transmit from the stage floor rather than being damped by the trolley.

This works the other way to reduce sound transmission in apartments. We are one of the peace-keepers of NYC (and elsewhere) because of our acoustic absorbent discs that we sell (stevespianoservice.com) that isolates the body of the piano from the building structure.

kpembrook:

Were these blind tests? That is the listeners did not know whether the piano was on trolley or not.

If not it sure was psychological.

Just a further comment...

In addition to the acoustic discs we sell, there's also the isolating caster cups by Piattino that also are effective at acoustic isolation.

This is a phenomenon that has been observed for decades (or longer) and is well-known by many -- although perhaps this is first-time information for some.

The psychological aspect was either minimal or non-existent because there was no beginning bias. All the listeners were piano technicians who had no vested interested in either outcome. We all were asking the question, "Is there anything audible to this notion that floor contact is better or is it just lore?" Nobody cared what the answer would be -- we just wanted to know. As it happened we all were able to detect a noticeable, audible difference when there was direct contact.

What was a surprise was that the pianist(s) noticed a difference in touch response as no one present had heard any idea of that aspect being impacted by the use of the trolley.

But both empirical results are supported by science: if one wanted to make an acoustic damper to absorb tonal or mechanical energy, constructing something with the leverage and acoustical mass of a spider trolley would be one strongly competive design.

Steingraeber Phoenix and the method I described both conserve energy. No damping is involved.

I second the Spiro test suggested by pyropaul.
IMO, nobody will tell whether there is a difference in a blind test.

I bet, if you play a single recording twice and trick the listeners that one was recorded with the trolley or isolators and the other was without, and want them to guess which was which, they would fall in the trick and answer accordingly.

It is just psychological.

Hakki, when you hear the Spiro test you will have to change your mind unless you are stone deaf.

Why is this so important for you?
Are you affiliated in some way?

Hakki, why not listen to what people say about what they heard instead of leaping to preposterous conclusions.

This is not the answer to my question.

The answer is to try it for yourself and let us know what differences you hear. Just like Mr Hough and Mr Swarzentruber. All you need are some lollipop sticks or felt punchings and a jack.

I say it is psychological, just like in the case of fooled wine experts. These things happen in life.

Let us just agree to disagree. The thread is deteriorated somewhat.

A number of years ago I was in a voicing class with Wally Brooks when this subject came up. He had a pianist play the piano and he walked over the the tail of the piano and picked it up. There was a noticeable change in the sound. There was nothing subtle about it. He lifted it several times so that there was no doubt. I won't argue if it sounded better or worse, but it did change the sound.

" I replaced the lollipop sticks with balance rail punchings"

Any compliant material like felt or rubber will act as a damper which isolates sound or other mechanical energy by turning it into heat. So yes, your approach damps sound and reduces the total energy output.

BII McKaig is spot on. No wonder Stephen Hough heard the difference immediately.

Ideally you need an air gap between the frame and the leg but that's impractical. You need spacers. The legs on the Ibach are 4 inches square at the top, an area of 16 square inches. Let's say the combined area of the screw and the punchings is 2-3 square inches, making the area of the air gap 13-14 square inches. That's more than 80% acoustic isolation.