Hi all,

I would be grateful for any tips that you could provide on how to test my current room before attempting to add some audio treatments. I’ll also need to be able to test it again and again as I go in order to accurately evaluate whether my solutions are working or not.

I feel that I’ll need to spend a decent chunk of time analysing the problem before jumping into attempting to solve it. It will also be handy to know how many overlapping problems might exist before getting too blinkered with focusing on just one issue. This might sound like stating the bleeding obvious, but I'd bet money that lot of home hobbyist like myself will cheerfully hang up a few blankets, nail up some useless egg cartons, or even build some bass traps and panels because they've read that they're good to have, yet not really understand the fuller picture. So we might fix an obvious problem with echoing, demonstrated when we clap our hands, yet create other issues in the process. Or tame some bass frequencies but deaden others, and so on.

I've already downloaded the Bass Staircase test file from here Room for Improvement and, sure enough, the variation across different frequencies was very obvious. Interestingly, I took it to a small local studio which does have some bass traps and wall treatments and you could still hear some variations there too. So lots to learn yet...

But I’m not sure what would be the best way to test right across the range. The resources page for Mike Senior’s book Mixing Secrets for the Small Studio (which I recently began reading) gives a similar file (maybe even the same one?) and says that it covers 24hz-262hz. But I haven’t seen anything similar for other ranges. Is it practical, or advisable, to home-make something that would do the job or are suitable solutions readily available? The range of possibilities across all the types of instruments that I might be dealing with seem pretty boggling - just going from bass guitar to a banjo is enough to make me feel slightly faint.

Fortunately, my current setup was not done with mixing or recording in mind, so it’s pretty terrible. It will show plenty of basic faults. As such, it should be a good project to learn on as it should be bad enough initially for me to be able to actually hear the improvements as I go. Of course I’ll be training my ears as I go along, as well as improving the room, so getting some good baseline info before I start the process should prove useful.

Any pointers about testing would be most welcome.

Thanks,

Chris

If it's of interest, here are some photos of the room, which is an attic measuring about 4.7 metres by 8.3m. It doubles as a spare bedroom and general hobby space so solutions that are flexible (i.e. partly mobile rather than all fixed) may be best.



Things aren't quite as bad as the second photo makes it look. For instance, the bench is already 20cms away from the wall, despite looking like it's right against it. But the first job will probably be to move the whole circus out of the corner and onto the end wall. (BTW the red thing on the left is a metronome, not a lava lamp... )

Quote Chris Charles:

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But the first job will probably be to move the whole circus out of the corner and onto the end wall.

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Hi Chris,

That should make a huge difference to playback quality - get your gear rearrangements sorted out (while as far as possible trying to make them symmetrical on either 'side' of the room) and then report back on how things sound.

Remember that many attic spaces will let some sound through the structure, so you may not have to install as many bass traps as you would in a more solid brick/stone built room.


Martin

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YewTreeMagic

Hi Martin,

Thank you for the reply and, while I'm at it, thanks for all your great articles too. Good point about the walls. It's a lightly built timber framed building so there's not a lot to stop the sound going through.

I'm currently trying to get my head around the various testing possibilities before I shift anything, and generally clean the space up a bit. It would be good to have some rather nasty baseline results to improve on.

I tried a LFSineTones test file for low frequencies and recorded it into my DAW with a mic about where my head goes, and it did a pretty fair job of showing how much the sound seems to vary through the range.

Screenshot of the audio


I also tried to make up a longer/wider file with a tone generator (16hz to 7900hz I think) but the results were pretty messy, with some sort of flutter or feedback going on (not sure of the right terms). That looked pretty nasty too.

Another screenshot (too wide to post)

Somebody suggested using a program called REW (Room EQ Wizard) but I haven't yet to manage to round up enough of the ageing brain cells to understand the instructions..... So I'll probably spend a couple more days (lifetimes??) trying to understand more about audio testing, and then start dragging the furniture around.

Thanks,

Chris

Hi Chris,

Glad you’ve found my articles useful

Room EQ Wizard is certainly the most commonly used free utility to test out the acoustics of a room (I’ve used it myself).

Your two plots look fairly typical in terms of peaks and troughs, and doesn’t actually seem too bad, although without any frequency or amplitude markings it’s difficult to draw many conclusions.


Martin

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YewTreeMagic

Quote Martin Walker:

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Hi Chris,

Glad you’ve found my articles useful

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Well, you seem to have the rare gift of writing articles about audio topics that I can actually understand!

Quote:

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Room EQ Wizard is certainly the most commonly used free utility to test out the acoustics of a room (I’ve used it myself).

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I recently read your article on using utilities for optimising studio acoustics (Here) and you mentioned REW in that. It may have been developed a bit more since then too. I'll get hold of a more appropriate test microphone and perhaps get the SPL meter they talk of too, and see where that takes me.

Quote:

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Your two plots look fairly typical in terms of peaks and troughs, and doesn’t actually seem too bad, although without any frequency or amplitude markings it’s difficult to draw many conclusions.

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Yes, I've been informed that they're very crude and don't tell very much, but it's a start...

My main aim is to enjoy the business of learning a bit more about the complex world of audio without busting too many of the last remaining brain cells, so I'm not in a hurry to get it all treated. Just getting my head around all the concepts will keep me happy for a fair while.

My other goal is to improve the space a bit for mixing but again, it's at a hobby level not pro. I also have the fallback position of doing some of the Mixing On Headphones (you again...) and checking regularly on my monitors (once I have at least some idea of where they tell lies).

Just out of interest, I tried another way of taking the room out of the equation today. We have good weather here, so I simply went right away from the house and set up in the garden. The test file came across as clean as a whistle! No dips, reflections, conflicts, etc. just a nice steady even tone. It could be the new craze - Mixing "En plein air" like some painters like to do. I thought they said that mixing could be intense - but they may have meant "in tents"???

Cheers,

Chris

Ah, but tents would only have an effect above 10kHz, due to their extreme thinness


Martin

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YewTreeMagic