Acoustic treatment for my little live/drum room

Hi all. My little studio is coming on leaps and bounds. The live room construction is now finished, and whilst dimensionally not perfect (by any means), the iso is superb, which was an unfortunate priority. The room is floating floors (4layers of flooring before final layer to keep res freq down), 2x4 stud walls (150mm min off original walls) stuffed with RW45 rockwool with 3 layers 13mm plasterboard, rotated so joins of previous layers are covered, and then a 5mm skim of plaster. Ive marked on the sketchup file where the ventilation enters and exits. So on to the acoustics... Id like the room to be bright and tight. 99.9% of what I do is rock bands, so its crucial the room is good for drums. Guitars, Bass vocals etc, I can find a nice spot in the room and close mic. The key is to keep the acoustic treatment:floorspace ratio good, so save as much space as possible. Ive attached a sketchup file, and some pics of ideas Ive had, so any comments, ideas, insults etc are very welcome. Many thanks, and I look forward to your thoughts. Oz

i think i'd build slat resonators all around to get the angles and then hang absorbers as needed. a couple of small clouds overhead, and maybe a small carpet if needed. this should keep the low and mids under control and keep a lot of life in the room. reversible absorber/partly reflective would be a nice feature.

Hi Glenn. Thanks for the pic. what do you think of this? I cant build helmholtz resonators on the back wall as there will be the power outlet conduit running its length. What do you think of just hanging panel absorbers there, and maybe angling the end two inwards like in the attached pic? I like the idea of building all slot reso's, then hanging absorbers on the front, if i want a more dead room. Also, Ill definaltely be hanging clouds from the ceiling, and the floor going in is wooden. Also, is it possible to tune the "back two" slot reso's to trap any low modal problems, and the "front two" (nearest the window and door) to be more broadband and go from low mid to high mid? Many thanks, Oz

Another quick question, The builders are using Rockwool RWA45 100mm for insulation between the studs. Chances are theres going to be leftovers, and I know they can get it for me at trade price if not, so I plan to use it for my acoustic treatment. Ive done some research and found its about 45Kg/m3, which is just shy of 3p.c.f. I understand 3pcf to be the magic number for acoustic treatment. Correct? I had a look on Bob Golds comparison site, and guess which was the only product not to have its absorbtion coificients stated :lol: :roll: So, anyone used Rockwool RWA45 for acoustic installations, or can anyone say whether it will or will not work? I get the feeling it will, but wanted to double check with the masters! Thanks, Oz

yeah version 4 should be fine. the rockwool leftover would be fine for the resonators and you could try it for the absorbers as well and see if it works. at worse case you need to invest in more/heavier absorbers.

Hi Glenn, thanks for your help so far. Work is starting on the LR acoustics as we speak, so will let you all know how it turns out. This is the fabric Im thinking of using http://www.whaleys-bradford.ltd.uk/prod ... ductID=135 Anyone have any thoughts? Its open weave muslin, and is flameproofed. Many thanks, Oliver

that fabric should be fine as long as you can get air through it.

Well its an open weave muslin, so hopefully it should be breathable enough. Thanks for all the help so far. Oz

Hi guys. The muslin has arrived, and is perfectly breathable, which is great. The framing for the resonators is complete, and I’m just working out what frequency they should be centered at, and how I will do it. If anyone has got 2 minutes to go through my workings, and check its correct, that would be fantastic. from my calculations (or the mode calc I got here :oops: ), the 1st and 2nd modes are 82hZ, and 164 Hz. I’ve attached my mode calc excel sheet, and the helmholtz calc res sheets for the two reso's. My main concern is that I’ve messed up the average cavity depth of the resonator. I’ve attached a pic to show my workings. I’d like to keep the slat widths and slot widths the same to make it easier to build. As the cavity depth is angled, I understand this will broaden the "Q" of the resonator anyway. I’ve also attached a pic of the framing. Your help is immensely appreciated. Oz

Bump! I know you guys are very busy, and i really do appreciate all the help you've given me thus far. On the home straight now, just want to get there things sussed. Thanks again. Oz

a quick way to verify - use the smallest, largest first, and average depth second. also, to be more effective, you can separate the well sections to isolate each of the octaves covered by the slats. so if your upper and lower range looks to cover 2 octaves, you should consider splitting out the wells on each octave. it will still work without this division but efficiency can be improved. in this case, you could put the close slots (3mm) at the top and bottom and the wide slots (12mm) in the middle and put in a divider where they slots change over. this puts the "air spring" for the lower frequency in 2 upper and lower wells, and the higher freqencies into the middle well. you could also take this further by some further sub-divisions to mix up the slats even more but this is probably close enough.

Thanks so much Glenn. I take it from your response that my calcs were correct. (IE 3mm gap with a 220mm slat=82Hz, etc) The resonators have been filled with insulation and covered with the material now, so the dividers are out of the question, but I will look into covering both octaves in each reso cavity. Im taking pics of each step, so will put up a "from start to finish" thread. Many thanks Glenn. Oz PS heres a cell phone pic of the slat wall with material. You can see the 703 used behind, but once the slats are in, it should darken it down a bit. Took a few hours to do this!

Hey all. First off, just wanted to say thanks for the all the help on this subject, speacially glenn. The slats are up, and Ive put a superchunk bass trap in 1 corner, and hanging panels round the rest of the wall. Testing the room next tuesday, so will let you know how it goes! Im gonna put a start to finish photo thread up on completion, but hear are some pics of the slat walls... Oz

Hi guys, Long time no post! Ive been running my place for a couple of years now, and just had the most incredibly busy summer you could imagine! I want to start tweaking the acoustics of both rooms a little, starting with this live/drum room. First off, I never got round to put a cloud up as due to the angles, track lighting and ventilation, it would look just wierd with just one or 2 panels up. What I want to do is make a 1x1" frame on the ceiling around the lights etc and fill with insulation, then cover with decent material such as guilford of maine etc. Then I was thinking about building a 1x2" frame on the far wall, filling with 2" rockwool insulation and having 5 QRD diffusers built into a symetrical pattern. Ive attached a picsof my ideas for the far wall. (Ive indicated where the tracklighting is installed also.) I tried to upload the SKP file, but it was too big?!? Does this all sound ok? One question i do have, is how do I drill into the plasterboard for fixing the wooden acoustic frames to without comprimising the isolation integrity? understand a lot of acoustic caulk will be some of the answer, but can someone whos done this give me a run down of what type of scew anchoring I need to attach the frames to the ceiling/walls, and how to create an air-tight seal? Once again, I look foward to all your advice, and thankyou in advance. Oz Hidden Track Studios http://www.hiddentrackstudios.co.uk