A while ago I discovered that my computer room tend to resonate pretty badly at about 120Hz. When listening to music sounds in that frequency area seems to make the entire room "rumble". It's pretty annoying, especially when playing music a bit loud. Now I want to try and eliminate the problem. Today I tried putting up some panels of foam on one of the walls. (Covering about 40% of the wall.) This helped a bit, but not very well at the frequencies that are the biggest problem. The overall sound in the room became a bit more "muted" which I think is pretty nice. I'm wondering if somebody have a good idea for some material to put up on the walls to dampen the resonance at low frequencies. I was thinking of some heavy curtains on all four walls, but I'm unsure how well they will work on lower frequencies. I want something cheap, but it should look OK as well. Any input is welcome
Are the walls hollow? Fill them with mineral wool if so. Have you got a carpet or a hard floor? Are you a Firefly fan?
The walls are already filled with mineral wool, but that's for sound proofing, not sound dampening within the room. I could of course put mineral wool on the walls, but that would make a lot of dust and itch pretty bad. And yeah, I'm a firefly fan, but red velvet isn't my thing. Black velvet could work, though
As far as I know, curtains are used more commonly in live music venues to "kill" echo and only have a very limited affect on reverb. To get rid of low frequency vibrations, I think you're going to need a shaped acoustic foam covering on the walls. This could be a very expensive process though. Is it something that you'd be willing to spend money on and get just right? Here is a source I use for acoustic foam for PCs, it'll give you an idea of what type of material I'm talking about. For a room, you're going to need a thick layer of dense foam with quite large (or agressive as I think they are reffered to) triangular peaks and troughs. From the website I just linked, this is officially referred to as an egg crate profile. I *sort of* know where you are coming from with this. In my own bedroom where my best hi-fi and speakers are, the new mirror on my wall above the hi-fi and the glass and mirror back in my model display cabinet opposite the speakers used to vibrate when music with low bass notes was playing at medium volume. I used a mixture of rubber mountings and gaskets on the glass in the cabinet to stop the vibration, and put blu-tack behind the mirror in several places to stick it to the wall and stop its ability to vibrate. [edit] Oh, look what I found I hope this helps
Those panels you linked to looks exactly like the ones I have on my wall at the moment. I suspect that they use a more dense foam, though. It's intended for shipping computer parts, so it's very light. I guess heavy foam is more suited for absorbing bass. Those corner blocks looks interesting as well. Maybe I need to alter the shape of the room? I was also thinking of adding another layer of drywall sheets (Gipsen/plaster boards) just to weigh down the walls to stop them vibrating. I would have to do all that work only to find out that it doesn't work, though.
I know the packing foam you're talking about, and it's nowhere near as dense as the foam I linked to, which is why (no offence) it's so ineffective. The acoustic foam is very dense and therefore heavy and really, you wouldn't believe it just looking at it. You have to pick a sheet of it up to feel the weight and understand how dense it is. From their technical data sheet (link for which is at the top of the page I linked to first) it weighs between 23.5 and 25.5 kg/m³ - that's pretty dense. You can use the data I've just given you, some volume per area calculations and this density calculator to work out how heavy a PC panel sized sheet of this stuff just an inch or so thick would weigh. As you've said, I think you need to alter the shape of the room to achieve the desired outcome. The bass traps would achieve this easily, and their description and your given scenario/question may as well be a matched key and lock from what I can tell
Yeah, I think you are right. This will probably get overly expensive, it seems. I have been thinking about a complete redesign of the room. Maybe I'll do it then. Anyway, thanks for the help so far
Take a look on Google for DIY bass traps. There are better ways of doing it that are cheaper than plastering foam panels around the room. One solution I've seen is to box three or four layers of tightly packed fibre insulation material into a box and hang that on the wall. A tube trap is another option. The first thing to do is to play a bass tone and move around the room to see whether there's a place (usually a corner) where the sound is loudest. That's the place to put the bass trap. If you're thinking about changing the layout of the room, see if you can do this while the room is empty. You'll probably need a few tries to get the location of the traps just right, but you'll know when you get it right
I did some searching and figured I could probably get a long way with some rockwool and some light fabric. I need to investigate further on exactly how and where to install panels / bass traps. That will be tomorrow when I'm awake. Thanks. It's a very good tip.
Those do absolutely nothing at all. There are only two things that will deaden low frequencies. Distance, and mass. I would recommend some panels of Owens corning 703 at least 2", preferably 4". Play a 120 hrtz tone and take a walk around the room. Make sure to crawl around as well and take a note as to which areas the tone seems to resonate the most.
Yeah, of course they do absolutely nothing. That is why people have been using them for years as a cheap/free method of treating the acoustics of a room, you know, to get that "doing absloutely nothing effect". I clearly dont know what I am talking about and have no experience in this field so must thank wafflesomd for showing me the error of my ways. But as I mentioned in my original reply they are not pretty especially for use in a residential setting.
Egg trays probably work, but not for my application. They will probably work just as well as the foam sheets I put up on the walls yesterday. They mute higher frequencies very well, making the room a bit more "dead". That's very good when for instance recording vocals or some instruments. However, music is composed of several instruments and contain lots of low frequencies which egg trays won't be heavy enough to eliminate, unfortunately.
Take your time and go through the designs that actually work before getting any actual work done in the room. There are plenty of bass trap designs/how-to's around the web and not all of them are necessarily too expensive and/or ugly. Also I take it you've already figured the best location for your speakers and yourself? I live in a stupid concrete building and it echoes like mad despite the bed, sofa, thick carpet and all sorts of stuff around. I just don't really have the money or chance to make any significant building here to get rid of the problem Also I'd think this forum has some good info on building better acoustics: http://www.avsforum.com/avs-vb/ And here might be something as well: http://www.diyaudio.com/index.php
Acoustically it's probably the worst position, but I don't have much choice. Not I have a L computer desk with my displays in the corner and the speakers sitting above the displays. I also have two 1metre wide closets sitting on the opposite wall. Problem is that there is a window on one wall, and a door on the other wall which makes two of the walls smaller. This means that there are no other place to put those two closets.
Oh that really blows. Despite the echoes in my room I luckily don't have huge issues with bass as I have pretty small speakers (Amphion Helium II) which don't go too low and a separate subwoofer which can be moved around the room to find the best spot.
Egg cartons might offer an almost unmeasurable amount of diffusion, but in essence, they do nothing. Only amateur kids would even consider using egg cartons for room treatments. Like I said. You can only stop reflections and absorb sound two ways, distance and mass. Egg cartons offer neither of those. Here's a good read. http://www.acousticsfirst.com/eggc.htm It looks like you'll experience very little absorbtion around 600hrtz. Compare the graph to this one of one sheet of 4" owens corning 703. Try asking around here. http://www.gearslutz.com/board/bass-traps-acoustic-panels-foam-etc/ They're smart enough to not suggest something as stupid as egg cartons.
He clearly cant help himself, no doubt over compensating for some inadequacy or other, most likely in the penis department.
Waffles knows his stuff Unfortunately the eggbox urban myth has been around for far too long. You can use them as a passable diffuser though. Basically, it 'breaks' (for want of a better word) the sound up as it reflects off the smooth surfaces of the walls so you don't hear a well defined echo, but rather a nice diffuse mix. Bass traps are definately what you need. you can build some useable ones out of hefty slabs of rockwool. A good way is to cut the rockwool into triagle shapes and stack them to give that toblerone prism shape which can then be tucked into a corner. However, you'll need to do a little bit of maths to work out the size that would be optimal to catch that 120Hz wave. Make sure to cover the rockwool with some acoustically transparent fabric though..... no-one likes inhaling fibreglass dust over a long period of time There's a wealth of info over on John Sayers studio design forums to help you out with that. Best of luck with it mate, smallish rooms in houses are a total pig to sort out acoustically, but it can be done well and very cheap with a little thought!
