Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum How much difference does hardwood floors make in sound?

Whenever I play a piano at the carpeted piano store, it sounds relatively muffled compared to my piano, even with the top wide open. My piano seems very loud in my house that has hardwood floor and a 9 foot ceiling with no furniture anywhere near the piano.

Just curious what other players have observed about the effect of home acoustics (hardwood vs carpet) on the sound. Has anybody found an improvement in putting an area rug under the piano?

Yep, there is a difference. If its too loud, I would start with putting a carpet under the piano. One that reaches under all three legs.

But, trying to compare different pianos in different acoustic environments is nearly impossible. As a technician I tend to focus on the mechanical feel of the action and the quality of the sound. To hear how the instrument plays into the room, I have to call in a professional and stand back.

Hardwood floors make a big difference. The more hard surfaces in the room, the louder the piano will seem. Curtains, rugs, wall hangings, tapestries, etc, can help within limits.

What is under the wood floor?
If there is air space under there and not concrete, the wood will vibrate sympathetically and could enhance the tone.
Especially if you have brass, not rubber casters.

It will make a large difference in the sound. Louder and brighter usually.

The piano is going to sound the same no matter where it is played. What changes is energy mix of the reflected sounds that reach your ears. Since quite a lot of the energy that reaches your ears is reflected energy from the floors, walls and ceiling your perception of your piano’s tone characteristic is heavily influenced by the acoustic properties of the room in which the piano is played.

Floor carpeting and/or rugs placed under the piano will affect the amount of energy reflected by the floor. The amount of sound energy absorbed by carpeting depends on the nature of the carpet and the frequency of the sound energy. Most carpets absorb very little sound energy at frequencies below about ≈ 250 Hz (A-37, or the fourth A from the bottom, has a fundamental pitch of 220 Hz). Most of the sound energy below ≈ 250 Hz that reaches the floor immediately below the piano will be reflected back into the room. It is above this frequency that absorption into typical carpets becomes significant and less energy is reflected back into the room.

Pianos with even moderately hard hammers will produce quite a lot of energy above 250 Hz. Without an absorptive carpet below the piano, much of this energy will be reflected back into the room and, ultimately, to your ears. Even a piano that would otherwise sound warm and mellow can sound bright and hard in a hard room; that is, a room with little sound absorbing material in it.

Putting a carpet or rug beneath the piano will absorb some of the sound energy above roughly 250 Hz which will make the piano sound a little warmer and not quite so loud. (Don’t worry; the effect is gradual so you won’t notice an immediate cutoff just above A-37.)

The general rules are:
— Rugs made of natural fibers such as wool are more energy absorbent than are otherwise identical rugs made of synthetic materials.
— Thick rugs are more energy absorbent than are thin rugs.
— Large rugs, by virtue of their larger surface area, will absorb more energy than will small rugs.

If placing a carpet or rug immediately under the piano does not achieve the desired result you might also try hanging a relatively large decorative rug on the wall opposite the open lid of the piano. Placing the rug about an inch or so away from the wall will increase the amount of energy absorbed by the rug. (The same, or better, results can be achieved through the use of specialty sound panels. But they won’t look as nice.)

Somewhere in there you should also have a chat with your technician about hammer voicing.

ddf

I have a 9 Ft. grand on a floor that's hard laminate over slab on grade. There are window curtains and leather couches, but other than that, the rest of the surfaces are drywall. Nobody's had a problem with it being too loud.

As for quality, it always sounds better to me when I'm anywhere other than sitting on the bench playing.... Though I think that's not entirely an acoustic issue. ;-)

What Del said.

Large scale instruments seem to have better sound starting from approximately twenty feet away.

If that is the case then the piano is not properly scaled for its environment.

Large pianos typically are scaled for large spaces. That is, their stringing scales tend toward relatively high-tensions and their hammers tend to be massive and dense. When these instruments are placed in small rooms they can overpower the room.

The solution, of course, is to design pianos specifically for smaller environments. Tone down the scaling, lighten up the hammers, etc.

Selling these pianos would, of course, require a fair amount of knowledge and sophistication on the part of the dealer. He/she would have to be comfortable getting away from the notion that only power, power and more power is the hallmark of a good piano.

ddf

As an acoustician by trade, it always bemuses me to read threads like this...

Del is mostly correct. Although, that ~250Hz rule of thumb is very approximate. The sound-absorbing properties of carpets/rugs vary quite a lot. Some can absorb well down to 125 Hz, other floor coverings don't start to display good sound absorption until 500Hz. So I agree to an extent. It's 250Hz plus or minus and octave.

(BTW: Paper towels and sponges are "absorbent". When talking about sound, us acousto-weenies like to use the word "absorptive". And don't get me started with "dampening" vibrations! Nails on a chalkboard!)

J.S. doesn't tell us how large the room is volumetrically that contains his 9ft. concert grand. Makes all the difference in the world. Likewise the volume of space in the typical piano dealership is likely to be much larger than one's living room. Apples and oranges acoustically - both for volume and room finish treatments.

I also appreciate Del's comment about scaling the piano for the environment in which is going to live. The wrong piano can easily overpower a room and its acoustics.

Here's a photo of a room I just finished for a customer. I was a bit worried that the piano would overpower the room. As it turns out, it came quite nicely. I have to admit, clients like this don't come along every day!
Features:
Hamburg D
Elliptical room in plan
14ft+ ceilings
3/4" thick sound-absorbing panels on the walls (yellow velour areas)
custom carpet
custom tuned Helmholtz Resonator bass traps (63Hz and 125HZ) behind the brown velour curtain - to take up where the absorption of the carpet and wall panels drop off. (See? Helmholtz was good for something!)

https://picasaweb.google.com/lh/photo/eBgLR8rmpPekXanolSaKei8wpnug0a_ZaLhxCkTeYmY?feat=directlink

Chris S.

Indeed, I didn't because it's so complicated. The main part of the room is 18 ft. by 21.5 ft. with a ceiling that slopes from 16 ft. down to 9 ft. There's a low ceiling (8 ft.) dining area completely open from the high wall, 10 x 12.5 ft. There are also a stairwell and a hallway to an open family room off the side wall.

In the house, the 9 ft. doesn't seem any louder than the 6-4 that I had before. But it wasn't until I got it that the neighbor across the street commented on my playing. I know, that defies the inverse square law....

Seriously, though, when these big pianos get too long in the tooth for a concert venue (mine's from 1929), they can be a real bargain for the amateur who has room for one.

Interesting input !

is mass necessary to lower the absorbtive frequencies (I mean no matter what thre shape of the material , i.e. acoutical foams, if the mass is not enough, the frequency absorbtive (!) range is above "250 Hz"

Do you know if a room can be tested for its own resonant frequencies with a single computer producing white (or pink ?) noise, and recording the noise at the same time with a (good !) mike ?

Just to find the peaks ... I have seen once a software allowing that, but i dont recall where ...

Thank you for your input

PS also .. did you separe the casters from the floor ? I noticed that some floors can be OK (even wooden floors) and wondered to what point grand pianos can be sesigned for some floor transmission (raising the lower frequencies by solid transmission)
I often install rubber or decoupling goodies under the casters on wooden floors, but on any stage the floor participate to the tone (not on US university stages as you use dollies/trolleys, the name escapes me, unless ome wooden blovs are used to restitute some solid transmission the vibrations may be reflected within the instrument and I wonder up to what level it is good for tone...

BTW I can recognize with my eyes closed, if the front casters are oriented front or rear ! (if I know this is the test conducted)

Wow, what a place for a 9 ft grand!

Too bad the architect of the Dayton, Ohio Riverscape Pavilion didn't consult with you before they built that acoustic atrocity. The canopy makes it the best possible example of how *not* to build a performance space. When a crowd is settling in to their seats, the noise of their reflected chatter is deafening. Performers can't hear themselves, and the audience hears only a blur.

But it is just a tent, something temporary, that can be dismounted anytime.

I hate outdoors tuning for the lack of sound return they provide. here the canopy may send a lot of noise and mixed frequencies .. horrible place for music indeed (at last if it rain you are not wetted)

The trick to tuning outdoors is to get the movers to leave some blankets, and then drape them over the piano and you while you tune.

ideal if the weather is bad you can also use the blankets for yourself, they rub a little but better than nothing !

I started doing this when it started raining when I was tuning. I found that it blocked the ambient noise so well that I ask for the blankets whenever I can.

Unfortunately it's not just a tent. It's a $2+ million pavilion with a permanent roof made of flexible material suspended from poles. Evidently sound reflected from the outside of a quasi-hyperbolic surface is just as problematic as that reflected from the inside.

No. You're confusing two principles. In general, increased mass is used as a way to BLOCK sound from going from one space to the next through a wall or floor. Blocking sound is difficult at low frequencies, and requires special techniques which may include increasing the mass of the partition separating the two spaces. Sound is ABSORBED by thick, porous materials, generally with very little mass. Absorbing low-frequency sound is also difficult, and requires its own set of special techniques (bass traps, membrane absorbers, etc.).



Now you're talking about room modes, which is entirely different than the previous two principles. Room modes occur when a wavelength of a particular frequency of sound corresponds to the physical dimensions of the room in question. They most often occur between parallel surfaces (there are three pairs usually in any given rectangular parallelpiped space), and can occur at integer mutiples of the fundamental frequency. The resulting audible effect one hears from room modes are hot spots and dead spots in particular locations at specific pitches. One can try and reshape the surfaces to avoid the parallelisms, make the surfaces sound-absorbing instead of sound reflecting, change the surfaces to sound-scattering, or just tolerate it. Steinway's selection room at the New York factory has one wall that's canted out of perpendicular, I presume to avoid the room modes between the parallel walls. Again, as an acoustician, I'm bemused because the other pair of walls is still parallel and the floor is parallel to the ceiling.

There are room mode calculators on the internet. They generally identify the room modes for rectangular parallelpiped spaces. These are the tools many recording studio designers like to use, but they don't have much practical application to the real-world living rooms we work in. One can also go to a built space and measure the room modes, but you wouldn't use noise for that.

I once had a client who was really disturbed by the room modes he heard in his living room. When I told him what was needed to correct the problem, he quickly decided he'd learn to live with the room modes. He moved the position of the piano to get his head out of the acoustical hot spot he was hearing, and then promptly found another hot spot at another pitch.


Again, I'm bemused at caster cups being sold as some kind of vibration isolation for pianos. Some of the hard plastic or wood cups I see provide no vibration isolation whatsoever - none (except maybe the psychosomatic acoustical relief they may provide which seems to be directly proportional to their cost). The softer rubber cups would only be effective at high frequencies. Most of the ones I've seen aren't calibrated to the weight of a piano and don't provide the appropriate deflection to even perform well at that. The piano overloads the rubber such that it's essentially a rigid block. The way to vibration isolate a piano is to put it on a raised platform supported on SPRINGS. Only springs have the deflection necessary to isolate low frequencies. How likely is it that one could get a piano owner to build a platform for a vibration isolation problem? Not likely.

With regard to resonant coupling of pianos to stage floors, and whether that affects tone: It depends on whether the piano's on a dolly or not, rubber wheels or nylon wheels, and whether or not the floor is constructed of soft hardwoord, (or hard softwood), or too thick, or too thin, how far apart the joist spacing is, finished, or unfinished, the weight of the pianist, and the type of nails used to secure the floor, or whether Beethoven himself might have once walked across it....I've heard it all. Good luck scientifically determining the factors which affect tone. Tell me what you think you hear. I'll probably just smile and nod knowingly.

Now! Piano techicians. Go! And use your newfound acoustical knowledge for good!

Chris S.