Eliminating impact noise from an electronic drumset (pedal)

tomarse · Post by **tomarse** » Tue Mar 06, 2007 6:31 am

Hi

I was wondering what would be the best method to eliminate "foot fall sound" (I don't know if that's the correct English term for what I mean) coming from the pedals of an electronic drum set. Just to make it clear, I mean the low-frequent sound (vibrations) that travels through the floor and walls of a building.
Since I don't know the correct term, I wasn't really able to use the search function of this forum software.

Anyway, I read about this issue in some drummers' forums and the most common approach was to build a kind of "podest", e.g. OSB board on some foam. Basically I'd agree with that approach. Though, the majority suggests not to cover the whole space between OSB board and floor with foam, but to cover only small areas with foam in order to reduce the area of contact. Is it really always better to reduce the area of contact, which means that there is more pressure on this smaller area?

What do you experts think about this? Why would this approach be better than spreading the pressure over the whole podest area, let's say 30-40mm of foam (those special, thick foam plates intended to reduce the "foot fall sound") over the whole area and on top 1 or 2 layers of OSB-boards screwed together (for more mass) or even glueing some concrete plates on the OSB board for even more mass? And then, of course, some carpet on top of that.

And one more question: If you put this kind of a drum podest into a room's parquet floor which is already decoupled from the concrete floor (you know, the ~2mm standard decoupling thingy in buildings of the past few decades), would this create a three-leave-design (concrete - parquet - osb-board) and therefore reduce the amount of isolation? If so, how to overcome this issue without removing the parquet or laminate floor? (Please don't tell me removing the floor is the only way.. I don't want to hear that

)
I attached a picture of what I mean, just to make it clear. From top to bottom:
OSB board
thick foam (blue plate)
parquet or laminate floor
standard insulation (pink .. sorry for that

)
concrete floor

Thank you! And sorry for my bad approach of describing in English. It's hard without knowing all the right terms for this specific topic. If anything's not understandable, please let me know and I'll try to explain better

Thanks so much!
Thomas

Post by **sharward** » Tue Mar 06, 2007 11:33 am

Welcome to the forum! Your English is great, by the way.

What you're describing is impact noise. Most people have problems with airborne noise.

Don't worry about how many leaves you have... I don't think they are very important in this case.

What you have read about the "elastomers" (foam or rubber "feet") is correct -- you probably do not wish to cover the entire area.

I would suggest you start with maybe 9 small ones -- one in each corner, one halfway along each edge, and one in the middle. Attach them temporarily. Try it out and see if that works well. If not, add more elastomers or make them larger. Make sure that there are enough to provide enough support but not so many that there's no "bounce" at all in the elastomers.

I don't see the need for all the heavy duty mathematics it would take for a full floated floor/room system, since you have the freedom to experiment and do "trial and error" testing.

I hope that helps.

--Keith

tomarse · Post by **tomarse** » Tue Mar 06, 2007 5:02 pm

Hi Sharward! Thanks for your reply

Sometimes I question myself, how stupid I can be

I think I've read the term "impact noise" a few hundred times within the last few weeks, but when I need to write it down, it does not come to my mind.

So thanks for helping me out there

As far as what I've already researched in this forum and other places, I thought a three-leave design would reduce the amount of LF-isolation. But if that's not the case here, I'm quite happy.

My question has now become more of a theoretic one, as I just realised that the space in my appartement is most probably too small for an e-drum, especially when I need to build this drum podest. The only place in my appartement would be in front of a not frequently, but still used door to the balcony. It's easier to put the TD-20 some inches away to open the door than tearing down a whole podest. I have to think about a different way because I'm not the only one in this appartement who's making the decisions

I just don't seem to understand why less area of contact would be better as pressure increases on the smaller area. And isn't there any possibility for resonance below the OSB-board if there is any air gap below. If you could help me out there, it's not that I don't believe you, but I always try to actually understand things.

Thank you so far,
Thomas

Post by **sharward** » Wed Mar 07, 2007 1:34 am

You are correct to be concerned about overloading the elastomers... But you should also worry about underloading them, as the results are about the same: no spring.

And to correct you on a couple of things: three leaves are not better than two for low frequency isolation (the opposite is true)... And a closed cell foam underlayment on a wooden or laminate floor does not constitute "air" in a mass-air-mass(-air-mass) equation.

Let us know if you get that drum kit.

--Keith

geoff_fry01 · Post by **geoff_fry01** » Wed Mar 07, 2007 2:05 am

sorry if you have allredy been there but try here... www.vdrums.com

there are others there who have build all sorts even "tennis ball" drum risers...

Cheers
Geoff

tomarse · Post by **tomarse** » Thu Mar 08, 2007 12:40 am

Now I see. So it would be the best bet to try from the least amount of foam and work my way up to find the right amount of elastomers, "the sweet spot". You're absolutely right, I was worried about overloading the foam and didn't realise that underloading could be a problem as well.

Regarding the three-leaves-issue... I think we both mean the same: three leaves are worse than two.

I thought a three-leave design would reduce the amount of LF-isolation.

I've not yet decided whether to get the drum kit or not. But I will keep you informed

Geoff, actually vdrums.com is one of the forums where I observed the drum riser discussions. But thanks anyway

Thomas

Ro · Post by Ro » Thu Mar 08, 2007 7:48 pm

Most common problem with electric kits is the kickdrum pedal. It'll wake up yer neighbors in a split sec if not isolated. It's not the airborn but impact noise that makes live hell. So yes, rise it.

TomM · Post by **TomM** » Fri Mar 09, 2007 2:54 am

how about green glue in this riser?

http://www.greengluecompany.com/dealing ... tNoise.php

Ro · Post by Ro » Fri Mar 09, 2007 4:57 pm

Yes, that'll do. There's much info on risers, use of GG etc on this forum. Use them stickies and search function to get yerself up-to-date 'bout both

tomarse · Post by **tomarse** » Sat Mar 10, 2007 2:35 am

Thank you guys for that information!

So I'm finally getting that drum kit. Today I went to the music store and played for nearly an hour. It's really amazing and even though it can not completely resemble an acoustic kit, it's quite good.

As far as impact noise goes: I'm living in an appartement in the second floor and have people living one floor below. The drum set will be set up in a room corner and the bass drum pedal will be set up about 4 feet away from the outer wall of the building (so I suppose it is a supporting wall). The floor is 9-10inch reinforced concrete as far as I know. Do you think there will still be some noise in the appartement below me?
I don't have many choices since I have only ~3cm (1 1/4 inches) of height to use for some sort of dampening since there is a door that needs to be opened from time to time.
I thought about getting a carpet and putting some foam (1-2cm; 3/8 - 6/8 inches) intended to reduce impact noise below.

That's the only thing that bugs me now. Whether this is enough or not... I really don't want to be a pain in the ass for those people in the first floor

Best regards,
Thomas

tomarse · Post by **tomarse** » Sun Mar 11, 2007 1:12 am

Regarding the impact noise issue, I'd like to have any of your thoughts on this:

I just tried it out by stomping on the floor with my heel and feeling the vibrations with my hand. The vibrations are only there in the same room (same flooring). When standing in the doorway, stomping on the floor of the left room and trying to feel the vibrations with my hand on the floor of the right room (or vice versa), I actually cannot feel any vibrations. So the only thing that seems to be vibrating is the laminate/parquet flooring.

tomarse · Post by **tomarse** » Thu Mar 15, 2007 12:41 am

So the concrete floor seems to be quite good to start with. I put 2 plys of impact noise insulation (5mm each) onto the parquet floor. On top of this, I put some rubber mats (14mm thick) originally intended to put under a washing machine and on top of that some woven cotton carpet. Seems to do the trick quite well for only 3cm of thickness, but I'm still looking forward to my TD-20 to arrive. Hopefully it will be delivered on Monday or Tuesday.