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Can a plug-in improve your monitoring acoustics?

A post by David Mellor
Thursday November 30, 2006
You can now buy a plug-in that claims to be able to fix any frequency response problems with your room acoustics. But surely to do this it would need to look into the future?
Can a plug-in improve your monitoring acoustics?

One major problem in recording and mixing is that the acoustics of the room you are working in affect your perception of the sound you hear from the monitors.

Depending on the dimensions of the room, its shape and contents, certain frequencies will tend to resonate.

This means that the air in the room will vibrate easily at these frequencies, and the vibration will continue after the sound source has stopped.

So consider a sound that is rich in frequencies - a kick drum with a hard beater. The signal from the speakers is short and quickly over. But the sound enters the room and certain frequencies resonate. So even when the kick drum beat has died away, these frequencies linger.

One effect of this is to introduce peaks into what can be considered to be the 'frequency response' of the room. It isn't a pure frequency response because it is an effect that occurs over a period of time, but the subjective effect is similar.

The natural reaction of the engineer to cure any perceived imbalance of frequencies is to apply an EQ correction.

But since this is correcting a problem that only exists in the room, and not in the recording, then the recording will actually have a dip at these frequencies.

Clearly this is not good.

The solution to this is to analyze the acoustic problems of the room and apply acoustic treatment. Absorbers can be constructed that damp the most significant of the resonances. It is also a good idea to have irregular surfaces so that strong reflections are broken up into weaker ones.

The problem with acoustic treatment is that it is expensive to do well. Actually, doing it not so well can bring significant benefits at very reasonably cost, but that's another story for another day.

If the problem is that the acoustics of the room are causing an apparent frequency response problem, then perhaps a reasonable solution would be to EQ the problem frequencies before they even enter the room.

So, for instance, if you are suffering a problem around the 100 Hertz region, then if you can EQ your monitoring so that less energy around this frequency goes into the room, then the problem should be at least ameliorated, if not entirely solved.

There is a certain logic in this, so clearly the option is worth considering.

To apply this solution, then firstly the room needs to be analyzed. You can buy a plug-in that comes with a measurement microphone specially for the purpose.

The software will generate test tones, which you sample with the microphone placed at various points in the room. The software will then calculate the optimum correction for your room. This is then applied to your monitoring, NOT to your recording.

Sounds good so far...

Although this solution sounds promising, it isn't a complete solution to the problem. The reason that it isn't is that it is trying to correct a time domain problem by applying a frequency domain solution.

Although your monitoring may now be pumping less energy into the room at 100 Hz (or wherever the problem area lies), those frequencies are still resonating in the room and 'hanging on' in the reverb tails longer than other frequencies. This will still affect your judgment of your recording or mix.

To effect a complete solution through software it would be necessary for the software to be able to look into the future and cancel out reflections before they had actually occurred. Realistically, this doesn't seem possible.

Trying to improve your room acoustics through software can only ever be a partial solution. But that does not mean that it is entirely useless. You will gain some benefit at a cost that is much lower than having your room professionally analyzed and professionally acoustically treated.

It may be that you consider your recording room as a temporary location. Believe me - I know from experience - if you convert one room of your house into a studio, then that house will be difficult to sell later on unless you go to the trouble and expense of converting it back.

Applying a partial solution may in this instance be preferable simply for economic and time reasons.

The last reason for wanting to try out a software solution is that when you see the analysis charts of your room, then you immediately learn something about your acoustic environment that you can apply to your work. Your recordings will be better simply from that knowledge.

And when you hear the treated results, you will learn something more - what the software thinks your room should sound like. You will be entitled to agree, disagree, or perhaps blend the information you now have with your own judgment.

Often people tend to fall into two camps regarding software 'acoustic treatment'. But even if there is no substitute for proper acoustic treatment, the software solution still has its merits and is therefore well worth considering.

A post by David Mellor
Thursday November 30, 2006 ARCHIVE
David Mellor has been creating music and recording in professional and home studios for more than 30 years. This website is all about learning how to improve and have more fun with music and recording. If you enjoy creating music and recording it, then you're definitely in the right place :-)