How will a lot of surfaces in a room affect acoustics?

[Komodovaran]

Like, all kinds of oddly shaped surfaces from objects such as tables, lamps, TV, etc., placed all over the room. Would they act as absorbing material, or breed more random reflections that screw things up? Moving into dorm room and my budget won't allow any larger operation, and I'm not allowed to mount stuff on the walls, but if I could spread out furniture to absorb as much sound as possible...

[H20nly]

sound bounces around. what instruments and/or live recording are you going to do in your dorm room?

being a purist audiophile in your situation is a little extreme. that's what headphones are for.

[Komodovaran]

No instruments. Sound source will be two 7" monitors and electronic music which can be heavy in the low end.

I just don't want the sounds traveling too much through the walls, annoying other residents. So I figured if I could absorb as much as possible by oddly dispersed furniture, might as well do that.

I know headphones are probably my best bet, but listening to speakers feels 1000x better.

[esky]

Go to gearslutz.com and learn how to build cheap absorbers on stands...this forum is full of ideas...

[southsounder]

Tables, lamps & TV's will do absolutely nothing to low frequencies in any size room. They might have a very small diffusive affect on high frequencies, but it wouldn't be controllable and probably wouldn't even be perceptible.

Couches and mattresses might help with high & low frequency absorption a little bit, but you'd need to fill your dorm room with couches to have any meaningful impact on the low end.

Neither approach would be predictable and the later runs the risk of make the acoustics worse by affecting frequencies unevenly - especially in a really small room.

Not sure if your budget is 'low' or 'non-existent', but the cheapest bet for proper acoustic treatment in a dorm room with precious walls would be to buy some 4" 703 or similar and make gobos that you can arrange against the walls in the proper location. Some 703, a bit of burlap, and a couple of 2x4's and you're good to go.

If that's not an option I'd leave the room untreated and use headphones for critical listening/mixing as mentioned above.

EDIT: basically, what esky said...

[Tone Deft]

of course it will. when the room is empty go into it and clap your hands once, lots of reverb. after you move in try it again, much less reverb. worst sounding room would be a perfect cube with the speakers placed right in the middle.

a sphere would be worse but imagine living in a sphere. you're not a fish are you? probably not, that would make logging in and typing a bitch but a spherical room would make sense.

go do your homework.

[southsounder]

I just don't want the sounds traveling too much through the walls, annoying other residents. So I figured if I could absorb as much as possible by oddly dispersed furniture, might as well do that.

I know headphones are probably my best bet, but listening to speakers feels 1000x better.

Yeah, forgot to mention - acoustical absorption inside a room has nothing at all to do with sound transmission through walls and being heard outside of the room. Gearslutz acoustics forum will help you understand some of the science behind this, but the bottom line is there really is nothing you can do on a budget to prevent low frequencies from leaving a small room. If sound transmission is a concern, headphones are your ONLY bet...

As far as controlling reverb time inside the room, clapping will show you if you've got flutter echos going on at the mix position but it really tells you nothing about the reverb time across the entire frequency range - especially lower frequencies. You really need to ring out the room to properly measure reverb time. Adding only high frequency absorption like 2" foam might help get rid of the echo you hear when clapping, but will actually make it harder to craft translatable mixes (been there done that). Same goes for furniture with unknown absorption coefficients - it can cause more harm than good unless you measure the effect and compensate with further treatment as needed.

Obviously in a dorm room you're gonna have a bed & some furniture regardless, so unless you're going to start looking closely at getting the room dialed in it's probably not worth your time worrying about acoustics any further than speaker placement. Especially given your sound transmission concerns and the limited size of most dorm rooms, spend your limited budget on a good set of headphones and call it a day.

[Forge.]

don't stress too much - if you have to live in a dorm, not much you can do about it. As others have said, there are 2 issues here - to avoid bothering neighbours you'd need to build a room inside a room. Not feasible. The reflections caused by objects are more to do with your listening experience, but you've got no chance of creating a perfect environment where you are, but people have made great music in terrible circumstances!

+1 on headphones, but actually you can do a lot at low level. This is why I like having a separate sub with NS10s - bass response on the NS10s is pretty poor, so I can control the low end totally by turning the sub up and down, which means late at night I turn it almost down, but can just faintly hear it for certain things when I need to. - maybe turn the NS10s off and just listen to the sub at low level.

If things sound good at low level, that's usually a good sign.