and what are acoustics anyway?

Let me tell you a story as I heard it from the late Dean Jensen who I stayed with in the early seventies when he was the top techo in LA. --- According to Dean in the early seventies some of the engineers of The Record Plant (one of LA's top studios ) were sitting on the roof of their building after a long party. They had taken some speakers from the studio up to the roof for the party and were discussing the fact that the speakers sounded great on the roof but were pretty awful downstairs in their control room! Why?? Well, on the roof the speakers were in what is called an anechoic environment - i.e. no reflections or reverberation! The sound left the speakers, went past them and didn't come back. Try it yourself - take your favourite speakers outside and set them up in your backyard or in an open field and have a listen to them. Suddenly the bottom end will be clean and tight and the top end imaging will be amazing. The centre will be really tight and defined and you will hear all the mistakes you made in the recordings. Unfortunately your neighbours won't let you set up a control room in your backyard. I might mention here that it amazes me how much EQ front of house engineers apply to speakers when mixing outside concerts where there are no room modes etc. I remember an engineer being highly offended (and confused da!) when I suggested that JBL must make shithouse speakers when they needed +/- 12db EQ in the open air. (I was the first in Australia to add 1/3 Octave EQ my studio monitors in 1974 when I got back from LA. Within 6 months I'd removed them.)

So what is the ideal internal listening environment? Well I reckon if you did a vote you would find that over 50% would say - In the CAR!!!. I agree, I often check a mix in the car and I know a lot of other engineers who do the same. So why does the car sound so good? There are a number of factors and it is these factors that go into making a good listening environment.

The main factors in a car are:

• The Shape: There are no parallel walls in a car and what walls there are are thin and curved.
• The Speakers. In a car the speakers are almost always flush mounted. i.e. They a mounted into a flat surface like below the rear window or in the side door panels. As a result there are no out of phase signals coming from the rear of the speaker. Also the rear speakers are mounted in a big cabinet - the boot.
• High Frequencies: In the car the windows are the main high frequency reflectors but they are all at angles (approx. 6 - 12 degrees)and are usually curved as well. The highs also get diffused evenly throughout the cabin by the dash board. Also the ceiling, sides and floor are covered in high frequency absorption.
• Mid Frequencies: The seats, door panels and passengers are all low mid to high mid absorbers. Modern cars have deep pile carpet on thick underfelt which also acts as a mid frequency absorber. Most of the car's acoustic treatment for cutting down engine and road noise is also on the inside and acts as acoustic treatment for the car stereo.
• Low Frequencies: The beautiful thing about cars is the bottom end response. With a couple of hundred watts a side, a sub-woofer under the seat and the loudness switch on the bottom end thumps away and sounds great. Actually most of the low end goes straight through the walls and disappears, consequently it doesn't hum around the internal body causing phase problems. Any vibration is dampened by the foam lining and carpet and as far as the low end is concerned the car is equal to open air. Next time you play a tape/CD in your car get out and listen to what actually leaves the car (most of it!! especially if the windows are open)

The problem with recording studios is that to keep external sounds out you land up keeping internal sounds in. People who build studios in the city have to worry about trains underneath, traffic noise outside, planes flying overhead etc. Obviously the best thing to do is to build it in the middle of a 50 acre paddock in the country where your only external noise concerns are birds, wind and rain. Then you can build a simple skin to keep the rain out and allow all the internal sound to get out so it doesn't muck up the sound within the room.

So how do you create the effect of your car, or the open air, in your studio? - By using Acoustics!! Treating the walls in your control room and studios so as to control the sound and thus improve the quality of the sound that you hear and record. I reckon good acoustics can beat a fancy effect unit any day and they cost about the same.

You can now select any of the topics listed in the adjacent column and progressively gain a good understanding of the basics of building a quality studio for yourself..