SOUND ON SOUND

[Hugh Robjohns]

Well having tried a sweep using make shift DIY traps made from mineral wool (from a roll) I can confirm it is absolutely useless. I did a scan from 40Hz to 500Hz and compared the two graphs. The mineral wool did nothing at all.

I've no idea how many, or how large and deep, your makeshift traps we're, but others have already pointed out that controlling low frequencies with rockwool traps is not easy, and to be effective they need to be REALLY BIG AND DEEP.

So rather than buy rock wool and go to all that effort of putting wood etc together.....Im just going to buy a couple of traps from Thomann.

I dont know the Thomann traps of which you speak, but my advice would be: buy with care! There are an awful lot of companies offering 'bass traps' that perform very poorly. Check the absorption coefficient numbers for frequencies in the range you need to control to ensure the panel will do what you expect...

[Sam Spoons]

If you are testing your 50mm DIY panels you mentioned earlier I refer you back to several references earlier in the thread that say thin lightweight panels will have little or no effect on bass frequencies but, as long as they are not too thin or lightweight they will do useful things in the mid range and above. There is no point in measuring 20-500 Hz to see what difference 50mm thick panels are making 'cos they ain't making any.

[TNGator]

Well having tried a sweep using make shift DIY traps made from mineral wool (from a roll) I can confirm it is absolutely useless. I did a scan from 40Hz to 500Hz and compared the two graphs. The mineral wool did nothing at all.

I've no idea how many, or how large and deep, your makeshift traps we're, but others have already pointed out that controlling low frequencies with rockwool traps is not easy, and to be effective they need to be REALLY BIG AND DEEP.

So rather than buy rock wool and go to all that effort of putting wood etc together.....Im just going to buy a couple of traps from Thomann.

I dont know the Thomann traps of which you speak, but my advice would be: buy with care! There are an awful lot of companies offering 'bass traps' that perform very poorly. Check the absorption coefficient numbers for frequencies in the range you need to control to ensure the panel will do what you expect...

What I tried was about 40cm deep by about 30cm wide. I would have thought that size would be effective. Yeah some of the Thomann stuff a coefficient rating but other models dont which is annoying. You would think that all items would carry this rating as standard procedure. The Absorb Coeff is probably the only thing you can really go on.

[TNGator]

If you are testing your 50mm DIY panels you mentioned earlier I refer you back to several references earlier in the thread that say thin lightweight panels will have little or no effect on bass frequencies but, as long as they are not too thin or lightweight they will do useful things in the mid range and above. There is no point in measuring 20-500 Hz to see what difference 50mm thick panels are making 'cos they ain't making any.

Hi Sam. No these were different. About 40cm deep. Do you know the funny thing? Just for a laugh. I put a 2 tier stand in the corner put some objects on it to make a make shift diffuser. And the darn thing did a better job than anything else I tried. The graph was really tamed. I couldn't believe the difference. So maybe some diffusion will help just as good as bass traps.

[Wonks]

With that method, you are probably just moving a lot of the problem nodes to another area of the room. But if it gets you the results you want at the listening position, then it's worth experimenting along those lines.

Diffusers stuck against flat walls are unlikely to do much for bass issues; it's the fact that you've effectively changed the shape of the room that you need to work with.

[Sam Spoons]

If you are testing your 50mm DIY panels you mentioned earlier I refer you back to several references earlier in the thread that say thin lightweight panels will have little or no effect on bass frequencies but, as long as they are not too thin or lightweight they will do useful things in the mid range and above. There is no point in measuring 20-500 Hz to see what difference 50mm thick panels are making 'cos they ain't making any.

Hi Sam. No these were different. About 40cm deep. Do you know the funny thing? Just for a laugh. I put a 2 tier stand in the corner put some objects on it to make a make shift diffuser. And the darn thing did a better job than anything else I tried. The graph was really tamed. I couldn't believe the difference. So maybe some diffusion will help just as good as bass traps.

Diffusion is, I believe (no personal experience) good at mid/high frequencies, maybe somebody will be along to say if it works at the low end, my feeling is that it will to a point by blurring the resonances

I suspect that in your room REW is not going to be your friend, you'll never get close to a flat graph and drive yourself mad trying (been there and bought the teeshirt :headbang: ). If you can set the room/monitors/desk up so you can get some absorbers at the mirror points and use headphones to check the bass you should be able to get back to the primary purpose of making/recording music*.

* I'm not suggesting you don't install bass traps just that you accept that they can only have limited effect in rooms like you (and I) have. In my room I have about 3m2 of 250mm deep traps and about 7m2 of 50mm panels, spaced 25-50mm off the wall/ceiling all constructed from RW3 Rockwool. I'd given up on testing by the time I came to install them and installed the full package in one go but, empirically, the room does sound much better.

[TNGator]

With that method, you are probably just moving a lot of the problem nodes to another area of the room. But if it gets you the results you want at the listening position, then it's worth experimenting along those lines.

Diffusers stuck against flat walls are unlikely to do much for bass issues; it's the fact that you've effectively changed the shape of the room that you need to work with.

Never thought of the fact the problem might be just moving. Ive been testing by running sweeps with REW in blocks. For example 40Hz to 500Hz. Then 500 to say 2K or something and so forth. Because of the point you make, I might do a full sweep in one go and then experiment. I can then compare the two complete graphs. Hugh was warning about buying bass traps as there are companies out selling stuff that simply doesn't work. I've noticed nearly all of the traps on thoman don't have a coefficient rating. I dont fancy handing over money on a gamble. Sending something that size back to germany for a refund would be a nightmare. Yeah I think I'll start from fresh and do a full sweep from 30 or 40 Hz all the way to the high frequencies.

[Wonks]

Don't forget that any low frequency stuff needs to take the LF performance of your monitors and your test mic into consideration. You need to allow for any fall-off in monitor and mic performance when considering the sweep results at low frequencies.

[TNGator]

Don't forget that any low frequency stuff needs to take the LF performance of your monitors and your test mic into consideration. You need to allow for any fall-off in monitor and mic performance when considering the sweep results at low frequencies.

Oh crap. I wouldnt have a clue how to test that or even where to begin. Opening cans of worms can be such fun. What have I done.

[Mike Stranks]

As you know, my room is even smaller than yours - and now I've measured it even smaller than I told you!

I think you've just got to accept that in these small rooms trying to sort the bass issues in the room is always a series of compromises and, IMO, not very successful ones at that.

Treat the mirror-points and get a good subjective sound at the mix position. Don't pump lots of bass into the room with large speakers. Concentrate on the mids and highs and use decent open-back headphones for checking bass.

My room is appalling for bass nodes; I've sorted the mix position and just let the rest of the room look after itself.

[Sam Spoons]

This ^ :thumbup: :thumbup: :thumbup:

[TNGator]

As you know, my room is even smaller than yours - and now I've measured it even smaller than I told you!

I think you've just got to accept that in these small rooms trying to sort the bass issues in the room is always a series of compromises and, IMO, not very successful ones at that.

Treat the mirror-points and get a good subjective sound at the mix position. Don't pump lots of bass into the room with large speakers. Concentrate on the mids and highs and use decent open-back headphones for checking bass.

My room is appalling for bass nodes; I've sorted the mix position and just let the rest of the room look after itself.

In the absence of a "mirror buddy" is it possible to just eyeball it? I have one of those laser spirit levels that fires a snipers red dot. I wonder if i shot the laser from each speaker to the wall would it give me an honest reflection point. My hanging duvet which is behind me must easily be covering the correct area due to its width. There are a few articles on this in various issues of the magazine. The speakers on my monitors are only 5 inch diameter so at least they wont be pumping out lots of bass signals. But good point, more bass into the room means more of a headache.

[Hugh Robjohns]

Yes you can 'eyeball' it -- the mirror point panels should be large enough that the positioning isn't too critical anyway. So you just need to remember that the angle of reflection equals the angle of incidence...

[TNGator]

As you know, my room is even smaller than yours - and now I've measured it even smaller than I told you!

I think you've just got to accept that in these small rooms trying to sort the bass issues in the room is always a series of compromises and, IMO, not very successful ones at that.

Treat the mirror-points and get a good subjective sound at the mix position. Don't pump lots of bass into the room with large speakers. Concentrate on the mids and highs and use decent open-back headphones for checking bass.

My room is appalling for bass nodes; I've sorted the mix position and just let the rest of the room look after itself.

PS...forgot to mention Mike...I was avoiding using headphones to mix but then I noticed you mentioned "open cans" not closed ones. Im guessing the open cans let in a little of the room?

[TNGator]

Yes you can 'eyeball' it -- the mirror point panels should be large enough that the positioning isn't too critical anyway. So you just need to remember that the angle of reflection equals the angle of incidence...

Thanks Hugh :)