Measuring the freq response in a room (mixing studio)

Doctor

Hi All,

Can anyone help me with some simple steps as to how to measure my room for frequency response?

Or possibly, the suggestion of a book or article.

Also, is SignalScopePro and SignalSuite capable of helping me?


Thanks for looking.

benfaber

Currently, we don't have any compiled tutorial information on making room measurements, although we hope to add some of that type of material to the website in the future. We are also working on some new software that will make room measurements much easier to perform.

Here are some basic tips.

You want to use a test microphone with a very flat frequency response, since your measurements will be biased by the microphone and loudspeaker(s). If you follow the approach discussed in the Articles forum, you will actually be measuring the loudspeaker(s), microphone, and any accompanying electronics in the signal chain (power amplifiers, mic preamps, etc).

If you want to perform narrowband frequency analysis, you would broadcast white noise through your studio speakers (using SignalSuite) and observe the frequency spectrum with an FFT analyzer (in SignalScope or SignalScope Pro). If you want to perform octave or 1/3-octave equalization, you would broadcast pink noise and observe the spectrum on the octave or 1/3-octave analyzer in SignalScope Pro. The chirp, random noise, pseudorandom noise, and MLS signals in SignalSuite can all be produced with a white (flat) or pink frequency weighting.

Whether you perform narrowband or fractional octave band analysis, you might want to use exponential averaging to smooth out the measured spectrum. When selecting the number of averages, more averages means more smoothing and less averages means a faster response.

One of the challenges of room measurements is that room acoustics vary over space as well as frequency. In other words, moving your loudspeaker or microphone to a different location in the room will produce a different frequency response. In a mixing studio, you are likely to use some permanently-installed loudspeakers, and it would make sense to place the microphone in several locations very near to your listening position within the studio when measuring the frequency response of the loudspeaker/room combination.

Good luck!

rcervant

Wow! This is very helpful for me.  But how do you do it for a church with a full conventional PA, full band, no sound obsortion system and a 250 person capasity?  Would it be best to do it durring a worship service while the room is full of people, or while it is empty?