I have just placed a new hybrid piano in a small 9x13 room in my apartment. I want to use the room for playing and for singing. Costly steps have already been taken, and, much to our dismay, we still need much improvement. At this point we have about $5000 left for the whole project.
The room's only direct connection to neighbors is through the floor.
A soundproofing company recommended MLV for the floor, but, since we still want hardwood, we paid $4200 (NYC) for the hardwood floor to be removed, 12mm thick Ecore installed using sound-dampening Bostik glue, and new hardwood floor again using sound-dampening Bostik glue.
Someone went to the neighbor's to test it, and alarmingly the sound is still quite present. (We don't have a solid before-after comparison because we only used a recording to test before).
Now: soundproofing company came back and said the next step is to install 1.5" thick melamine tiles on a portion of the walls. We need to decrease the reverb in the room, but he says that this will also assist somewhat with the transfer to the neighbor, since there will be less sound to transfer.
I have a terrible feeling it isn't going to help as much as I want it to.
So, I asked a soundproofing specialist, and he said this, which discouraged me:
"By simply soundproofing the floor does not stop flanking noise from the 4 walls in the room sending sound to the downstairs neighbor.. What I do not see is decoupling for low frequency and lots and lots of Mass. Ecore is for footfall and impact but is not going to perform as you would expect for low frequency. This requires far more attention to decoupling and mass."
I told him that we are trying to manage this without opening up the walls.
He said, "Without decoupling, your chances of reducing low frequencies becomes minimal, which would require opening the walls or take a risk on a triple leaf system.
"As for the absorption aspect, yes if you address corners and cover the majority of the walls you would reduce some of the sound pressure levels and therefore reducing some of the transmission.
"The real question would be how thick would you need to go to see cost vs reduction..
"Are you handy? if so maybe a DIY 4"-6" thick mineral wool or cotton fiber panels. if you make your own, you can add a septum of mass loaded vinyl, which would give e bit more help in the low frequencies since you do not have much mass on the walls."
It's becoming apparent to me that there are lots of differing opinions on this. I wonder if crowdsourcing here on this site could help me? It doesn't have to be SILENT by any means, because the neighbor is understanding. And yet, for a total of $9000, even in NYC, one would think that a lot could be accomplished?