Basic acoustic treatment help?

[Ermz]

I know that the general consensus is 'go to John Sayer's' forum and read about everything in depth. I've bought the 'Master Handbook of Acoustics' and in realizing that it's going to take me the better part of several months to read, re-read, absorb, re-absorb and then finally be able to apply the principles and theory taught within, it became clear that I need a quick, stop-gap solution for my mixing environment in the meantime.

Basically, I have a rather rudimentary mixing set-up in my bedroom. The bedroom is entirely untreated and it shows in the form of flutter echo and some nasty modal problems, like a severe ring at 127Hz.

I've taken some quick snaps of every side of my room and am hoping that some of you can chip in and tell me where I can throw up some absorbing foam, whether to think about diffusion, bass trapping etc. For a quick fix that will give me a deader and slightly more even mixing environment until I verse myself in the extensive lore that is acoustics.

The pictures start facing in the direction of the mixing position and go anti-clockwise around the room. They're not the clearest photos in the world, I understand, but they're just to give a basic idea of surfaces, room layout etc.



My first thought here is some foam directly on the back wall and some corner trap or another on the right to kill some of the whoompy bass.



Doors here so not much that can be done it seems.



The shelves and random stuff here may provide some degree of diffusion?





It's hard to see what's going on here, but it's basically just a blank wall, with a bed at the bottom. This is directly behind the mixing position and would be the main cause of flutter echo in the room. Is it a better idea to attempt some diffusion boards here, or just absorptive foam?





Yep, a huge window to the right side of the mixing position. Suggestions very much welcome!




Okay, on top of that the floor is carpeted & the ceiling is basically just blank, as the back wall is.

Any suggestions on what to put where, and what sort of product to look at are very welcome!

PS. My monitors are evidently low and aren't at ear height unless I slouch back in the chair. Is there any good options for raising them up off the desk without using random stuff to prop them up?

[Skyweaver]

Heya Ermz,

you need a bookcase filled with porn in it to soke up any "nasty" frequencies lol

[devouredremains]

I would simply recommend bass traps and some type of diffusion to either side of your mixing position/sweet spot to start. With the large window you most likely have to move your desk in order to properly treat the room. Do you track any loud instruments in the room or is it strictly for mixing? What volume levels do you mix at?

If your only mixing at nominal volume levels in this room bass traps would be a good place to begin. Track down some Owens Corning 703 and get the girlfriend/wife/mom to sew up you up some bags or buy some pre made bags from Ready Acoustics.

http://www.readyacoustics.com/index....ls&prod=RT424B

You will also want to measure your room and download ModeCalc (free). It will give you a better idea of what your about to tackle.

http://www.realtraps.com/modecalc.htm

Acoustics are the one area that cash alone will not help you unless you are literally building a room for the sole purpose of audio. It can be frustrating but just take it one step at a time.

EDIT: For a low cost recommendation concerning your monitors, stacked cinder blocks can make great adjustable monitor stands with next to no resonance.

[Nebulous]

I would +1 to looking into making your own bass traps for that immediate corner to the right, and possibly even another in the right wall behind you (next to the window). Also, head down to Clark rubber and get some large sheets of their highest grade acoustic foam (which is still abit thin, but does the job). If you go with what I've done; one sheet the length of your desk and almost one meter above the desktop, you will get some nice imaging improvement. If you're really hearing those flutter echoes and want to reduce them, I'd say the ceiling would be the next best place to look at.
The best thing there would be some foam hanging from the ceiling at about the mid point between the top of the foam you'd have on your "monitor wall" and the ceiling. This you might like to make in a way that is removable daily as you'd probably like to walk freely in your room. The back wall you could either deck out with some foam, or just use your pillows/ covers to get some height and stop the lower reflections.
As for that window, I would probably go with some foamed-out go-bo's (which again, you could either leave in place or remove to aid in using the room). This would be best accomplished with either some simple timber frames, about .5m wide with foam stapled/ nailed to them, and if you'd like, also apply some thin plywood to the back so they last longer and possibly help 0.1% with isolation haha.

You know my experience and "expertise" in this area already. I've done some experimenting at home with the foam that I bought and pillows/ couch cusions etc. You could ealisy remove the flutter echoes and improve the imaging IMHO, but as for the isolation and bass problems, it would probably depend on how much money, room and to what extent you're able to move/ modify the room.

I'd be happy to help with bringing down some foam to see where it works well so you could decide how much to buy.

[sparkyness]

Yep...the standard box room scenario. I've had to treat a few of these over the years.

The suggestions so far have been on the money....Bass Trap every corner with 4" rockwool (or similar). Where there's a door in the corner (I have the same problem) you can put the trap as close as possible to the corner either on the back of the door or on the wall itself (i've done this) rather than across the corner. You could also look at adding traps where the wall/ceiling or wall/floor join too. You can never have enough trapping in a room of this size/shape. I'd add some 2" rockwool traps or acoustic foam to either side of the mix position but as you have a window you could use a gobo of some description. That funky bay window could also cause some imaging issues, but the gobo would help with that too. A cloud over the mix position would be also be a good idea. Putting the bookcases and whatnot behind the mix position will work for a bit of diffusion too.

Also, (if possible) if your room is rectangular rather than a perfect square, make sure the desk is placed so that your speakers are pointed at the longer of the two measurements. The desk should be placed so that when in your mix position your head is 1/3 of the distance of the room from either the front or back walls. I can't tell from the photos if your monitors have bass ports on them but if they're on the back of the speakers (my old Tannoys were) you might want to plug those up to avoid any nasty bass resonance off the wall behind them. If they're front-ported they'll be fine.

Other than that.....John Sayers forum is awesome with loads of suggestions for rooms like that....

[Ermz]

Thanks a lot guys.

I've been given a suggestion which may alleviate some problems outright without any spending. That is to set my mixing position up so that im facing the window. That lets the mix position face the longer part of the room (it is indeed more rectangular than square), gives me some diffusion from the book cases and shit at the back, and also frees up the two parallel hard walls for as much deadening as I can muster. Also it will allow me to keep the desk further back from the walls and have the speakers closer to the center of the room.

Thanks again. Keep the suggestions coming!

[unsilpauly]

Originally Posted by Moonlapse

Thanks a lot guys.

I've been given a suggestion which may alleviate some problems outright without any spending. That is to set my mixing position up so that im facing the window. That lets the mix position face the longer part of the room (it is indeed more rectangular than square), gives me some diffusion from the book cases and shit at the back, and also frees up the two parallel hard walls for as much deadening as I can muster. Also it will allow me to keep the desk further back from the walls and have the speakers closer to the center of the room.

Thanks again. Keep the suggestions coming!

yep, re-arranging the room will help a lot. steer clear of the foam. rockwool or rigid fiberglass is cheaper and works a million times better. put four inch rockwool or rigid fiberglass in the corners and behind the desk, and two inch on the walls and over the mix position and you will be in business. put the shelves behind you for some diffusion. then when you can get some diffusors for the side walls towards the rear and some on the ceiling. i dont know about australia but in the states it would cost under 200 bucks for the rockwool and then some fabric to cover it so maybe 300.00 for the whole room. you would need at least two thousand dollars worth of foam to get close. go the do it yourself rockwool route and you wont be sorry. i am in the process of getting more myself right now for the tracking room and a few more in the control room. good luck man.

[smy1]

Don't forget one over the desk too ...

[unsilpauly]

Originally Posted by smy1

Don't forget one over the desk too ...

try two or three if they are 2x4 foot pieces.

[James Murphy]

I'd move that desk so that the window is behind it.

[Ermz]

Yep the desk is going on the window side for sure. Just need someone to help me lift the damn thing!

RE: The rockwool and fiberglass, how should they be mounted in the corners? Do I need to make traps out of them somehow?

[Nebulous]

I was thinking about this last night whiel trying to sleep (but failing) in the heat- check that wardrobe. Take measurements, see what frequency you might have building in there, if any. Once you move the desk, also try standing in it (the wardrobe) while music is playing and check that the 127Hz isn't resonating in there. You might like to try that with the corners too, check to see if the frequencies differ, or where they might be strongest.

[Ermz]

Shouldn't the wardrobe technically be acting as a pseudo-bass trap of its own accord?

I'm considering a smaller desk and speaker stands to increase decoupling. This thing really is overkill to a large degree. I don't really know where to look into decent stands and desks though.

[Nebulous]

That thought also crossed my mind, hence why it would be best just to take a step in and listen. Maybe sit at your desk and check the diff between an open and closed wardrobe door.

[unsilpauly]

Originally Posted by Moonlapse

Yep the desk is going on the window side for sure. Just need someone to help me lift the damn thing!

RE: The rockwool and fiberglass, how should they be mounted in the corners? Do I need to make traps out of them somehow?

just wrap the panels in fabric and rest them in the corners. doesnt have to be fancy(or it can be if you want to build the frames for them). i just used a 2x4 making a triangle in the corner and put two big "hooks" coming off of the 2x4 and they just rest on the hooks and against the corners. it took about 10 min. per trap. they really work better than the auralex corner traps(lenrd) that i had before.

[smy1]

Yep. Dont overthink it. Paul is 100% right. There is not much you need to know. In a nutshell:

Put the desk facing the window, with your head at 38% length of the room. Desk should be equally apart from the longer walls.

Rockwool or Fiberglass in huge amounts in every corner.

More of that left & right of the desk.

More of that in the back of the room (into the closet? or you can actually hang the panels ON the doors with these door-coathanger-thingies).

More of that over your desk.

More of that where the window is.

More of that on the side walls.

If you do that by just wrapping the panels in fabric, you will be done in less than 1h and your room will sound 7824962347 percent better.

[Ermz]

Thanks guys. Can I expect to be making the frames for the rockwool myself, or can it be purchased already done? I've heard that handling rockwool can be tricky as it may be hazardous to our health. Also, is there a preferred wood for the frames, like MDF?

[Soundlurker]

Rockwool is just itchy, not much of a hazard to one's health. You'd want to leave as little unprotected skin as possible because it's not very easy to get rid of the fibers. As for the frames, I think anything will do. I chose to cut my own pieces from particle board because it's much cheaper than solid wood but it backfired on me, as it's a pain in the ass to put screws through that thing.

[Nebulous]

In Ermin's situation, is there a point at which he could be using too much rockwool, creating too much of a dead space?

[Ermz]

I don't think so. As long as the back wall is left largely diffused, and the ceiling only partially treated, I think it should be okay. You gotta keep in mind that I also can't do much with the window. The largest danger zones, as the guys have pointed out, will be the two hard, blank parallel walls and the corners. Now all I have to do is find an Insulation retailer that sells quality rockwool, and somewhere else to work up some wooden frames.

PS. I just have one more large question when it comes to constructing the panels of rockwool (my biggest ??? point, since I'm not a good craftsman). Should I create the panels so that the rockwool is sandwiched in between two layers of wood? Pine, ply, MDF? Or does the rockwool openly face the inside of the room (with say a thin covering of cloth over it)? I just figure that being the foamy shit it is it'd start falling out or whatnot.

[unsilpauly]

Originally Posted by Moonlapse

I don't think so. As long as the back wall is left largely diffused, and the ceiling only partially treated, I think it should be okay. You gotta keep in mind that I also can't do much with the window. The largest danger zones, as the guys have pointed out, will be the two hard, blank parallel walls and the corners. Now all I have to do is find an Insulation retailer that sells quality rockwool, and somewhere else to work up some wooden frames.

PS. I just have one more large question when it comes to constructing the panels of rockwool (my biggest ??? point, since I'm not a good craftsman). Should I create the panels so that the rockwool is sandwiched in between two layers of wood? Pine, ply, MDF? Or does the rockwool openly face the inside of the room (with say a thin covering of cloth over it)? I just figure that being the foamy shit it is it'd start falling out or whatnot.

you dont have to build the frames. if you can just rest them on some type of mounting scheme, you may not need the frames. i dont personally feel the need for the frames. some people think they work better without the frames. if you do build the frames, you will want to cut them out so the sides will still absorb well. and yes definetly dont have wood on the front face, just cloth. good luck dude.

[Ermz]

Thanks Pauly. My main concern about not getting frames is that I'm in a rental property... so I need these things to be transportable to a degree. I wouldn't know how to mount just plain rockwool either. Would you recommend any particular type of rockwool either? There seem to be quite a few versions out there, some more rigid than others.

[unsilpauly]

Originally Posted by Moonlapse

Thanks Pauly. My main concern about not getting frames is that I'm in a rental property... so I need these things to be transportable to a degree. I wouldn't know how to mount just plain rockwool either. Would you recommend any particular type of rockwool either? There seem to be quite a few versions out there, some more rigid than others.

the kind i have is mineral wool fiber 8lbs density. owens 703 or 705 rigid fiberglass will work as well. i think rockwool is a brand of mineral wool fiber.
the four inch thick usually comes 3/pack and the two inch comes 6/pack all should be 2'x4' in size(8sq feet). as far as mounting them goes, all you need is something for them to lean against. i have gotten these "hooks" that are kind of square shaped and they are a screw on the other end. the flat side of the hook is about four or five inches long and the panels rest in them great. go to the hardware store and see what they have. even if you just prop them up on something like a foot or two a high then they will be in the middle of the wall basically since you dont have high ceilings.

[smy1]

If you are not thinking about treating your room ...

This thread should have all the info you need (including "how to build"-pictures from my own home room). I made a mistake by using plastik bags on the back, but it still sounds good. Read all the posts in this, there is very good info.

[Ready Acoustics]

Good info so far.

I'll be emphasizing a bit of what has been mentioned so far, but will add a few things to the discussion that I hope you will find useful.

Build your own bass traps and install them in your room as shown below:




Here is an Over Head image of the same thing:





Make your own bass traps. It's easy, and this will be the single best thing you can ever do to create a great sounding recording, mixing environment. It will have the single greatest impact on how your music sounds in your car, boom box or any other medium on which you might play your music. No amp, preamp, converter or anything else can make this big of a difference in how you hear your music. I guarantee it.

Build: When building your own bass traps, use rock wool, OC703, or another 3lb pcf acoustic insulation. Use a fabric you like and that fits your style. Make sure when you hold the raw fabric up to your lips and blow, that it offers a modest amount of resistance (at least). This will ensure that insulation fibers will not creep out of your panel and into your room.

Here is a DIY Bass Trap tutorial that utilizes materials you can find locally. This is based on a design created by the folks at http://forum.StudioTips.com.

DIY Bass Trap..." target="_blank">DIY Bass Trap...

Here is some additional, useful information to consider when setting your space:

4 Rules for Broadband Acoustical Treatment for Critical Listening Environments


1. Lay your system and listening position out symmetrically – Acoustically render the left half of the room as an exact mirror image of the right half of the room, especially the part of the room and system components in front of the listener – asymmetries behind the listener are less of a problem than asymmetries in front of the listener.

2. Use broadband absorbers [minimum 4” / 100 mm thick] so that your treatments work on all frequencies [lows, mids, and highs] in a linear fashion [evenly / smoothly].

3. Smooth out the non-linearity of very low frequency resonances which exists in all small rooms by installing 4” thick corner mounted treatments. As a standard guide for optimal treatment, add a pair of vertically stacked 4” thick corner panels in each of 4 room corners [total = 8 corner mounted bass traps]. If vertical corners are not available, then use any available horizontal corners [ceiling/wall or floor/wall corners]. If you cannot install 8 corner panels of 4” thickness, then use thicker panels in the corners you do have available.

4. Treat Early Reflection Points with additional broadband absorbers. As a standard guide for optimal treatment, hang a pair of panels on the front wall, 1 panel each on the side and rear walls, and 3 panels on the ceiling – each located so as to mask the first reflection points [total = 8 reflection point panels].

I hope this information is useful to any interested in a great sounding room, mix, etc. It truly is the best upgrade you can make to your space, and may be one of the least expensive when you consider DIY options.


Joel DuBay
www.readyacoustics.com

www.basstraps.net