Sound On Sound Magazine
I always go to the book store and buy Sound on Sound magazine. Sure, I could get it on line, but I like the physical magazine. I like reading it instead of looking at my computer screen all the time. A magazine is a good break from the electronics. I can also carry it around in my computer bag and pull it out and read it instead of turning on my computer. It is immediate and without thought or much effort.
Room Acoustic Articles
I always like reading the articles on room acoustics. I like the ones where they start with an existing room that an artist has occupied and wants to record and playback music in. It is usually a control room, vocal booth, and recording forum all rolled into one room. The acoustic treatment is usually centered around taking the room out of the mix.
In the latest USA issue of Sound On Sound magazine, there is an article by Paul White entitled, “Studio S.O.S. Your Studio Problems Solved”. In this article, Paul takes us through a series of acoustical treatments and the sonic improvements that they make. Lets examine each one and look at the improvement in sound each one makes.
Lets look at our room size. It is a very small room. It is two meters wide and four meters long or roughly 6 1/2′ x 14′ long. It is an acoustical nightmare for any low frequency response even with a concrete front wall. We also have 3 other walls made out of plasterboard, which will go diaphragmatic and start moving at the first sign of any low frequency pressure. on top of all of that, we have another studio in the room next door. Can we help this room achieve some type of low frequency response?
We have one wall to work with, the rear wall. It appears all the other walls are taken with album cabinets and guitars. If we can afford to give up 12″ from the back wall, we can reduce low frequency pressures enough so that we can hear bass notes and then be in a better position to manage the bass in our mixes. We can install a diaphragmatic absorber within that 12″ space. It would need to cover the whole wall.
Another option is to place diffusion on the rear wall. Diffusion will eliminate that time delayed signal that bounces off the rear wall back into the mix position. Diffusion will also acoustically add some depth to the room. It will reduce reflections and spread the reflected energy over the listening or monitoring position without the use of absorption.
Side Wall Reflections
Paul also treats the front and side walls with an acoustical foam . Side wall reflections are an issue always. They are really an issue when the room side walls are so close together. When the room boundary surfaces are physically close to the mixing position, side wall reflections will create a comb filter soup that will wash across the mixing position. Placing acoustic foam on the side walls will reduce the reflections time signature below the direct sound from the monitors. Placing foam on the front wall helps focus and define our sound stage at the mix position.
The monitors are placed on vibrational isolating pads that are termed high density foam pads. These foam pads provide an isolation barrier that separates the monitor physically from the console and the pad will drain the amplitude out of the vibrations from the monitor. These vibration pads will also bring a focus and clarity to the mid range. It appears to me that most small monitors I have heard have a desire for a smoother mid range, however one accomplishes that.
No Air Leaks
Paul also talks about the door and all the areas for sound to enter. A room is only as good acoustically as its weakest link. If our door is leaking sound energy, the smallest leak can be very damaging. We must plug all air gaps. A wall or door that has air gaps in it is like a dam that is leaking. It will constantly pour unwanted sound into the room. This sound then adds to the pressure level in the room and one has to mix around it.
Sleeping Bag Absorbers
Paul also came up with a good idea using the sleeping bags to absorb rear wall reflections in the vocal booth. Rear wall reflections at the mic position in our vocal booth are acoustically destructive. The rear wall must be treated with absorption technology. The sleeping bags are a good start to help the artist realize that particular acoustic impact in their mixes. When more funds become available, we want to eliminate the sleeping bag and look to a good closed cell foam for the vocal booth. Closed celled foams are better for vocal rooms over open celled foams. Closed cell acoustic foams have a smoother and more natural absorption response curve for vocals.
Treating a small room is no easy task. However, if one plugs air leaks and treats primary and secondary side wall reflection points one can begin to realize that a good sounding room is a little like love. Love is not just one thing. It is a series of little things added together that produce something that is larger than each one of its parts. Take your time and enjoy the journey.