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Tackling room resonances

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Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 10:23 am
by Sam Spoons
TNGator wrote:
Sam Spoons wrote: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.

Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 10:51 am
by TNGator
Wonks wrote: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.

Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 11:00 am
by 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.

Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 11:07 am
by TNGator
Wonks wrote: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.

Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 11:28 am
by 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.

Re: Tackling room resonances

PostPosted: Sun Aug 11, 2019 3:59 pm
by Sam Spoons
This ^ :thumbup: :thumbup: :thumbup:

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 9:36 pm
by TNGator
Mike Stranks wrote: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.

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 9:41 pm
by 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...

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 9:47 pm
by TNGator
Mike Stranks wrote: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?

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 9:48 pm
by TNGator
Hugh Robjohns wrote: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 :)

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 10:15 pm
by Sam Spoons
TNGator wrote: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?

Open cans don't really let any room in because you are not exciting the room but they do sound more natural.

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 10:17 pm
by TNGator
Sam Spoons wrote:
TNGator wrote: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?

Open cans don't really let any room in because you are not exciting the room but they do sound more natural.
Ah. Yeah I dont mind cans when recording or lets say listening to educational vids when trying to hear the effect of an EQ or compressor. But i couldnt mix with them. Id feel closed in and claustrophobic.

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 10:48 pm
by Mike Stranks
Have you ever tried good open-back headphones? All headphones are not the same... :lol:

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 10:51 pm
by TNGator
Mike Stranks wrote:Have you ever tried good open-back headphones? All headphones are not the same... :lol:
No Mike, I only have a pair of closed ones. They are great for recording but Ive never tried open ones. Might be worth investing. Like closed ones, are these designed for studio use as opposed to everyday hi fi headphones?

Re: Tackling room resonances

PostPosted: Mon Aug 12, 2019 11:17 pm
by Sam Spoons
TNGator wrote:
Sam Spoons wrote:
TNGator wrote: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?

Open cans don't really let any room in because you are not exciting the room but they do sound more natural.
Ah. Yeah I dont mind cans when recording or lets say listening to educational vids when trying to hear the effect of an EQ or compressor. But i couldnt mix with them. Id feel closed in and claustrophobic.

Nobody is suggesting you mix exclusively on cans, just that you can use them to check the bass.

Re: Tackling room resonances

PostPosted: Tue Aug 13, 2019 7:34 am
by TNGator
Sam Spoons wrote:
TNGator wrote:
Sam Spoons wrote:
TNGator wrote: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?

Open cans don't really let any room in because you are not exciting the room but they do sound more natural.
Ah. Yeah I dont mind cans when recording or lets say listening to educational vids when trying to hear the effect of an EQ or compressor. But i couldnt mix with them. Id feel closed in and claustrophobic.

Nobody is suggesting you mix exclusively on cans, just that you can use them to check the bass.
Worth a shot. The car test or Ipod test will be needed in the end to check the sound outside of the room.

Re: Tackling room resonances

PostPosted: Tue Aug 13, 2019 8:27 am
by Mike Stranks
TNGator wrote:
Mike Stranks wrote:Have you ever tried good open-back headphones? All headphones are not the same... :lol:
No Mike, I only have a pair of closed ones. They are great for recording but Ive never tried open ones. Might be worth investing. Like closed ones, are these designed for studio use as opposed to everyday hi fi headphones?

Yes; there are many different brands, models and prices of open and semi-open aimed at the studio market. People here who've commented use various makes and models, but some 'firm favourites' are:

AKG K701/702/712
Sennheiser HD650

and others that will doubtless be mentioned!

Re: Tackling room resonances

PostPosted: Tue Aug 13, 2019 10:19 am
by Sam Spoons
TNGator wrote:Worth a shot. The car test or Ipod test will be needed in the end to check the sound outside of the room.

Yes indeed :thumbup:

Re: Tackling room resonances

PostPosted: Wed Aug 14, 2019 8:39 pm
by TNGator
Now this is interesting. So i was watching a vid done by Bobby Owsinski (apparantly a well known mixer etc). He was addressing a college in Canada and talking about home studios. As part of the usual DIY suspects such as Rockwoll he also mentioned everyday carpet underlay. Does it work? Well its not something that's expensive at all so I guess worth a shot. So i was looking at a web site here in Dublin of carpet suppliers and looked their underlay stuff. Have a look at his. Its a product called Acoustalay. And it says in its specs it has a 19dB reduction. It appears to be a product to install if perhaps you live above someone and dont want noise disturbing them.
Now, at only 20 euro for a roll certainly worth a shot. But should we avoid a product that boats sound proofing as opposed to sound treatment. After all, sound proofing and sound treatment are very different animals. I'd never heard of this product before. Anyone here ever come across this?
https://www.ie.screwfix.com/polyolefin- ... y-15m.html
I then found this site in the UK also selling the acoustalay product.
https://www.soundreduction.co.uk/sectors/domestic/

Re: Tackling room resonances

PostPosted: Wed Aug 14, 2019 10:00 pm
by Sam Spoons
Sounds like it might work as a 'limp mass membrane' but you'd need to check prices of 'proper' stuff.