John Sayers' Recording Studio Design Forum Archive

Hi

I'm benoit bel, engineer producer and owner of http://www.mikrokosm.fr, a recording facilitie based in France.
Since we opened in 2011 we dealt with several small issues in our control room in studio A which is mainly a big resonating frequency around 120 Hz.
For many reasons, back in 2011 we had to open very quickly to satifsy some clients demands so once construction was done we put up all the setup in custom-made producers desk hosting the custom 32 channel Studer 169 we have + other equipment + patch.
We put our monitors on top of that and since we recorded and mixed non-stop.

We learned how to deal with those acoustic problems, and tried many many different sets of speakers, placements, acoustic treatments to figure out this was just coming from the producers desk itself.

This is not an option ot remove or swap it right now but maybe some custom wood work would help it a bit?
It's all made of 19mm plywood, it has 2 19' racks wings hosting equipement and patch, they're linked by a wood table screwed to each racks on which the studer is.

Is there any "easy" way to fix this problem?

Thanks a lot

Hi Benoit. Welcome back! It's been quite a while since you were last on the forum. It's good to see your studio finished! It looks very nice (I just took a quick look at your web site).

OK, so you have identified a problem at around 120 Hz, and you suspect that it is related to the desk/console. That might well be true, but I'd need a lot more information to be able to help fix that, and I also suspect that this is not your only issue: I see several issues with the way the control room is set up and treated that lead me to think there are very probably other problems in there. The issue at 120 Hz is probably masking those, so you aren't really noticing them yet, but you will, once the 120 Hz issue is fixed...

The good news is that I think it probably is possible to fix your problems and get your room usable. I would aim to get it compliant with ITU BS-1116-2 specs, or the similar EBU-3276 specs. Those are the specs that I normally shoot for when tuning a room. It probably won't be possible to get there completely in your room, but you an get close in most aspects.

Here's an example of a room that I have been working on the for past couple of weeks, to show you what can be accomplished:

http://www.johnlsayers.com/phpBB2/viewt ... =2&t=20471

That room does meet the specs (and exceeds them, in fact!), but it took a lot of work to get there. Compare the graphs of the original room response, to the graphs after I finished tuning it.

So your room can be fixed, or at least improved, but it's going to take time and effort.

To start, please do a set of tests on the room using the REW acoustic software, which is free, and post the resulting MDAT file some place where I can download it. Make sure that there is no equalization or filters at any point in the signal chain: It must be completely flat from start to finish, so turn off all EQ that you might be using: on the mic itself, the mic pre-amp, console, interfaces, DAW, speaker management, and on the speakers themselves: I need to see the actual raw response of the system and the room.

First calibrate REW with a hand-held sound level meter (not an iPhone app!), set up your system so that each main speaker by itself produces 80 dBC at the mix position on your hand-helpd meter. Then do set up your measurement mic accurately at the mix position, 1.2m above the floor, and angled upwards at 60°. Do three REW tests initially: one test with just the left speaker on, one with just the right speaker on, and one with both speakers on. Do not change any settings between tests!

Then do a second series of tests, but this time with both main speakers on, and each time move the measurement mic back towards the rear wall in steps of 20 cm. In other words, each new test is done with the mic 20cm further back than the previous test, but still on the room center-line, still aimed upwards at 60°, and still at 1.2m above the floor. If you fill up the MDAT file like that before you get to the back wall (there's a limit to how many tests you can have in one file), then save that file and do a second file for the rest of the measurements. The files will be big: perhaps 70, 80, 90 MB or so. You will have to upload them to a file sharing service, such as Dropbox, then post the link here on the forum.

When I have a chance I'll download that and take a look at it, to see what I can figure out, but I already have my suspicions about where that is coming from.

Problems at around 100-200 Hz are very common in small rooms such as yours. They can usually be fixed, with varying degrees of success. If you look at the graphs for the room at that link above, you'll see that we started out with a major, huge dip at around 160 Hz, and some serious ringing at about 110 Hz. Compare that with the final result...

Is there any "easy" way to fix this problem?

Probably not, no.

But there ARE ways to fix it! They just aren't easy.... In acoustics, "easy fixes for major problems" are usually not possible. You can't cure a heart attack with a band-aid, but you can cure it with major surgery. Your room might need some surgery to fix it... (As you already found out, acoustic band-aids did not work!) So you'll need a surgeon, but the good news is that the patient will probably survive, and live a long, healthy, happy life afterwards... _:)

The question is: Are you really willing to do surgery to make the patient well? Or do you just want to leave him sick, wheezing and moaning like that forever?




- Stuart -