Looking for acoustic treatment tips for small rooms in living apartments

[ATN69]

There are various ways to get rid of sound reflections. This page illustrate some ideas in a good way,

http://www.acousticsfirst.com/acoustics ... erview.htm

Rockwool is very good for absorption but another way to reduce reflections is to use diffusers.

[recursive one]

As far as the measurement mics go...

Thing is that if I buy just a mic I will basically use it only one time - when making the measurements. I thought that instead of that I may buy a room correction system, such as IK Multimedia ARC or Sonarworks Reference, which come with some measurement microphones.

So I could
- make the measurements with the included mic and sofwtare and see the room frequency responce
- run the correction process and adapt my monitors to the room before doing any treatment - I guess it still would be far from ideal but I hope I'll get at least some improvements in my monitoring before I can do the treatment
- do the actual treatment with the panels, bass traps and stuff and then run the correction process again to additionally correct what wasn't improved enough
- if something changes or I move to a new location I could run the correction again

How do you think, are these room correction systems any good (as an addition to an actual room teratment) and if yes, should I go for ARC or Reference?

[ATN69]

I got the Sonarworks reference 4 with their calibration microphone and it works fine. The graph you get after calibrating your monitors it very telling. It will show you where you have peaks and dips. Since good monitors have a quite flat frequency response by it's design, the dips and peaks you get in the Sonarworks calibration graph normally comes from your environment alone.

In my case I noticed that low frequencies up to about 200Hz were increased and some frequencies between 500Hz to 1kHz were decreased in the calibration. The practical sound after calibration changed quite much. It all makes sense because I know that I often went a bit bass heavy in my mixes prior to the calibration.

[recursive one]

Thanks! I will consider getting Reference 4 (also it seems easier to buy in my country than ARC)

Do you have any actual treatment in your room?

[jlaws]

Don't get foam. It's not going to be nearly as effective as rockwool, Owens corning 703, etc. Pay someone to put them together or buy pre made ones if you don't want to diy. If you're not cutting the Batts, you won't produce much in the way of dust, just wear gloves because you will get itchy if it comes into contact with your skin. Reference 4 is great, but you need treatment, as well, since it can only boost or cut to overcome room modes but it will not stop certain frequencies from ringing nor can it fix big nulls that you'll most likely have in a room without treatment.

With a bit of treatment and some experimentation with placement using room eq wizard or sonarworks 4 you will probably be able to find a decent space with a reasonable frequency response curve.

[recursive one]

Thanks, yes that's basically the plan: I do the treatment then additioanlly refine the sound of my monitors with Reference 4.

As far as the materials go, I'm pretty convinced than rockwool is much more effecive that foam, the problem is my son seems to be allregic for some construction materials, so even if the panels are made not at home if they still emit some smells this may problematic.

[jlaws]

Ah. I can’t be sure of that because it would depend on his specific allergy, but if you do decide to use rock wool, find a brand that doesn’t off-gas and make sure in your construction of the bass traps that you use a design that covers the batts with cloth, front, sides, and back, as some designs only cover the front and sides.

My wife has quite bad asthma and allergic exercises and she hasn’t had any issues being in my room with lots of these bass traps for extended periods of time. That doesn’t mean that your son won’t have issues, though, so maybe you can make one first and see how he reacts?

Lastly, foam, even fire resistant foam, can catch on fire. Rockwool brand insulation and other decent brands are incombustible.

[ATN69]

Thanks! I will consider getting Reference 4 (also it seems easier to buy in my country than ARC)

Do you have any actual treatment in your room?

I don't have acoustic treatment in my small studio room. I rent this house in Hong Kong and there is a clause in the contract saying that I can't drill holes in the wall and similar. I need to find another way to put up panels on the wall. It mustn't be too bulky either because my room is very small (approx 8 sqm).

[jlaws]

You can stack insulation rolls in 2 of the corners of the room. Otherwise you can hang broadband absorbers from stands like the gik stands. They will take up some space though so it depends how much stuff you have in your room.

[a_Scientist]

Thanks! I've read advices like that, seems to work as an auxiliary measure. For what I know also big curtains help to some extent (like basically everything which is big and soft), while glass surfaces like mirrors should be avoided.

Big curtains, I had them in a room. Certanly yes.

[recursive one]

Thanks everyone!

Now I'm looking for an opportunity to construct the bass traps and the panels not at home.

Looking at this pic, there are several variants for corner bass traps, I think the "straddled bass trap" would probably be the easiest to construct and mount, but it will be thinner than "triangular infill bass trap" occupying the same space. On the other hand the "straddled" trap will have some air behind it.

How thick should be a "straddled" corner bass trap be in order it could actually work? Does it depend on the rockwool dencity? They sell 45 kg/m3, 60 kg/m3 and 100-125 kg/m3 rockwool here (60 kg/m3 is optimal afaik).



The pic is from here

http://www.masteringmastering.co.uk/che ... ixing.html

[jlaws]

The thicker the bass trap, the less dense the material needed. Thickness should be 4 to 6 inches with 6 being better than 4. Density for 4 inch traps would be around 60 to 70 kg/m3. youre right in that the air gap and being situated in a corner will enhance the low frequency absorption of the trap. Soffit traps or corner traps would be more effective. since they'd be thicker, you'd need less density. It's going to be harder to make the soffit or corner traps (especially the triangle traps since they don't make Batts like that AFAIK), though, so bear that in mind.

[camsr]

While foam is a combustible, usually also are the coverings for mineral wool bass traps. With only coverings, there is less material, so that's a pro, but the incombustible coverings are usually more expensive, which is a con. With foam there is no need for a covering, that's it's pro, yet the price is higher which is it's con. Make sure to figure in the cost of covering mineral wool before dismissing foam. And don't play with fire in your studio.

Insulation still bundled in it's packing is usually very compressed and has way too much air flow resistance to be useful. It's very inefficient when used that way. Plus it looks awful. Not an option IMO.

I would not do speaker calibration before and after as was described, but only because it seems like a waste of time. There's no reason not to, if you at least know what the unfiltered measurements are.

[recursive one]

In my city there is a shop which sells their custom foam bass traps. This seems to be the most hassle-free option, I just buy them and mount in my corners (the simplest way seems to be to glue them on the walls but in this case there won't be any air gap left, but I can figure out some stands or something). I can afford enough of these to cover all my corners and there will be some money left for wall panels.

This is the absorption graph for these traps (I assume it doesn't take into account any air gap)

The Y axis is an absorption coefficient, the X axis is frequency in Hz



This is a graph for 6 inch thick mineral wool 60 kg/m3. I'm not sure how accurate it is, I just found some gas flow resistivity figures for mineral wool of different density on Gearslutz, so I'm not sure how these figures are applicable to different mineral wool brands (Rockwool, Knauf etc)



I used this tool to create the graph, for the sake of more correct comparison I didn't input any air gap.

http://www.acousticmodelling.com/porous.php

Looking at these graphs alone it seems that the absroption coefficient is more or less similar, at least I don't see any really drastic difference in 100-200 Hz area (the foam trap seems even better at 200 Hz). Maybe there are more correct graphs to be found somewhere? Or are there some other factors besides the absorption coefficient which I should take into account?

I know that foam is combustible but I don't smoke (I vape ) and there won't be any sources of fire in my studio room.

As for doing the speaker calibration twice, there are no "technical" reasons for this, I just thought that I could buy the correction tool a couple of months before I can do the actual treatment so it could help my mixing for this time. I understand that after the treatment is done the results of the calibration done in the untreated room would be basically useless.

[camsr]

This is a graph for 6 inch thick mineral wool 60 kg/m3. I'm not sure how accurate it is, I just found some gas flow resistivity figures for mineral wool of different density on Gearslutz, so I'm not sure how these figures are applicable to different mineral wool brands (Rockwool, Knauf etc)

The answer is, unfortunately, not readily applicable to other brands.
You should use the random incidence setting for these tests since the sound will be bouncing all over the room regardless.
I would not worry too much about the calculator at this time. Test your room acoustics first.