Did a first room equalisation of the garage. Pretty damned cool.
What's that?
Let's say you have a cinema auditorium with a Dolby Digital processor. You have three screen channels (left, centre, right), two surrounds (left and right surround) and a subwoofer. Something like this:
How these channels actually sound in the auditorium depends on things like the speakers, the power amplifiers feeding the speakers, the room's characteristics, and so on. In other words, it varies depending on lots of things, and unless something is done, no cinema will ever sound like another, which is not what the filmmakers spending millions on good sound mixes want.
This is true whether your auditorium is a 700-seat theatre or a 12-seat garage.
For this reason, Dolby cinema processors include equalisers for each and every channel. Each equaliser will have 1/3 octave controls from roughly 20 Hz to 16 kHz which means that by changing the frequency response for each individual band, you can compensate for the oddities in your particular setup and achieve the sound the filmmaker wanted.
This is done by placing a microphone connected to a real-time analyser (RTA for short) in the auditorium, running pink noise through each channel and then observing the resulting sound curve on the RTA screen. The curve most likely looks like a mess, initially, but can be corrected using the equalisers to something like this:
You will also attempt to change the subwoofer's response to something like this:
Your actual results will, of course, always be a compromise, but I'm sure you get the idea.
In my particular case, my left and right channels are brilliant, the surrounds OK and the sub decent, but the centre sucks, probably because the speaker itself is bad. I' going to replace it and see if I can do a better equalisation of that channel.
You did ask.
