Upright Piano Room Acoustic treatment.

george4u
New Member

Posts: 2

Upright Piano Room Acoustic treatment. Jul 28, 2016 9:16:39 GMT

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Post by george4u on Jul 28, 2016 9:16:39 GMT

Hi I have a Piano room, where I have an Upright and it has a Reverb problem in my Piano room.

The room dimensions are 14 feet X 10 Feet, and the upright Piano is against the longer wall.

The walls were made of drywall panels with rockwool stuffed inside (with no airgap).. and the wall is 100 mm thick (ie the wall panels have aprox 100 mm thick glass wool pack in between.
I am planning on making a modification on the existing drywall behind the Piano by adding to the wall a sound absorbing panel to work together with the existing dry wall as under:

I plan on having
1) An Outer Porus fabric covering with 12 mm foam layer ( for echo absorption) fixed to
2) a 6mm MDF perforated board (with several holes of 1 and 2 inch dia to make it porus)
3) to this i plan to place on a grid network of wood strips to hold inside 50 mm thick new glass wool panel (for sound absorption), after this
4) a 12 mm soft foam ( to act as air gap) and this will rest on the existing drywall..... Now I am not yet finished here..
5) so to this existing drywall, I plan to make perforations on the side attached to the absorption panel, (only those areas directly behind the upright piano ) to make it porus so that sound which escapes from the absorption panel described above, can further travel right through the wall and into the glass wool and get absorbed/killed.

Pls advise if this is the right approach to get rich sound over the sound frequencies for an upright and avoid reverb.

I calculate that this method will make the effective wall absorption thickness becomes close to be close to 50+100 mm of glass wool depth plus 12 mm of air gap (made of soft foam).
Thereby for me the only additional panel thickness is actually reduced to (12+50+12)mm only since the dry wall of 100 mm thick is already existing.

Good to get advise is this method will work well. I plan to do this panel right behind the upright covering aprox 8 feet wide and 9 feet tall.

Thanks for a quick reply.

George

rock
Global Moderator

Posts: 893

Upright Piano Room Acoustic treatment. Jul 28, 2016 12:40:16 GMT

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Post by rock on Jul 28, 2016 12:40:16 GMT

Hi George,
First, are you sure the piano is not the source of the reverb? If the dampers are old and the damper felt is hard and "crunchy" or the dampers or pedal are not properly "regulated" (fancy piano tech term for adjusted), it can sound like reverb. No acoustic treatment will adequately fix the problem; you need to hire a piano tech (or buy a new piano:)

From your plan, it sounds like you are focusing all your efforts behind the piano (the soundboard). If you just want to quiet the piano down a bit, this would make sense. But if your problem is too much reverberation in the room, you need to treat all the surfaces in the room somewhat equally. If you don't want to lower the piano loudness, I'd forget about the area behind the piano soundboard altogether; it won't do much anyway. A simple test is to stand in the middle of the room and clap. you can move around and see how the reverb sound changes in different places, this will give you an idea of where the flutter echoes are the most. Parallel facing bare walls are the culprit. Floor to ceiling too.

A carpet or thick rug on the floor will help and is probably the easiest and fastest and possibly cheapest. If you use an area rug, consider a felt pad under the rug. Carpeted floors always have a pad but you can specify felt instead of foam if the installation is new. After the rug, if the room is empty except for the piano, (other furnishings like upholstered chairs will help), and still has reverb and flutter echoes, hang absorbers on the walls, alternating on opposing walls will do the trick, spacing panels off the wall (equal to the thickness of the panel i.e. 2" to 4") will allow the panels to work at lower frequencies but your main problem is mid to high. 2" thick panels are adequate but 4" thick will also provide, more LF absorption to reduce room modes and ringing, which is not what I think you're hearing but if you have the resources, I think the treatment job will be much more comprehensive.

Cheers,
Rock

Last Edit: Jul 28, 2016 12:44:56 GMT by rock

rock
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Posts: 893

Upright Piano Room Acoustic treatment. Jul 28, 2016 13:32:36 GMT

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Post by rock on Jul 28, 2016 13:32:36 GMT

Just for fun, regarding pianos and reverb: Did you know you can make a piano into a reverb effect unit? Try this simple experiment: (it's easier on a grand with lid propped up but you can do it on a vertical with knee board removed...it comes off easily usually with a spring clip kinda thing). Simply hold the damper (right) pedal down and get your head as close as you can the the strings and soundboard and SHOUT into the piano then listen. You'll hear your voice sustaining back at you. That's it. The combination of all the strings selectively, sympathetically vibrate at the frequencies and harmonics in YOUR voice. If you have never done this, it's pretty cool. Now if you didn't have a digital, plate or spring reverb, you could place a contact driver on your soundboard and with a mic, pick up the reverb output all in an isolated room. Wire this in your FX loop and there you go! Have fun!

Cheers,
Rock

george4u
New Member

Posts: 2

Upright Piano Room Acoustic treatment. Jul 29, 2016 2:33:48 GMT

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Post by george4u on Jul 29, 2016 2:33:48 GMT

Thanks for the advice Rock,

Well yes I want to quiet down the piano a bit, and focussing behind the Piano is the first source to look at since the upright is designed that way.

The piano is in good condition with the damper felt still good, pedals and tunning regularly checked by a Piano tech, so i think the Piano is ok.

Your suggestion on the carpet is a really good idea to try out.

Wanted to get some feedback on the technique that I want to use by combining the wall insulation with the acoustic panel added to it.

I shall try the Reverb effect at a later date and post a reply, my sons would love this if its as you describe.

Cheers
George

adamforemusic
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Posts: 14

Upright Piano Room Acoustic treatment. Jul 29, 2016 7:04:44 GMT via mobile

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Post by adamforemusic on Jul 29, 2016 7:04:44 GMT

Hi George,
I also have an upright piano which I use to record. I think that treating all the areas around the instrument would be better than just one wall with extreme treatment, this is if you want to lessen the reverb in the room. For example like rock said lay a carpet underneath, hang some absorption from the ceiling example OC 703 or Rockwool RW5, at 4 inches thick and spaced away from the ceiling, same with the wall behind the piano, absorption 4 inches thick spaced a few inches away from the wall will work well (the further from the wall the better the low freq absorption. If it's a big room then you could DIY build some gobos (freestanding absorption panels) to surround the piano, either way treating the parallel sides in the room will be beneficial. If it's sound isolation you are trying to improve also then build a partition wall with 3 layers of plasterboard/drywall, seal any joins layer by layer and fill the behind it with fluffy loft insulation.
Hope this helps,
Adam

Last Edit: Jul 29, 2016 7:06:07 GMT by adamforemusic