Tag Archives: recording studio design

Simple Broadband Absorbers

Here’s how I built a pair of simple broadband absorbers to cut down the room sound in my studio. These work as good as specialized acoustic treatments, but cost far less, and their absorption is good down to the 500Hz region, and it’s fairly flat across the spectrum. Note that absorbers don’t stop outside sounds from getting into the studio… they do shorten the reverb time of instruments as they are played in the room.

The absorber starts with a simple 1×3 wooden frame.

It’s really nothing more than a simple wooden frame with fiberglass fill, covered with cloth. Mine measured about 5’6″ by 30″. I used cheap 1×3 lumber (which is really about 5/8″ x 2 1/2″), but a true 1×4 would be better. If you use cheap wood, count on spending more time building them… I had to pre-drill all the nail holes to prevent the weak wood from splitting. I also used construction adhesive on all the joints.

The frame gets filled with plain R13 fiberglass. A few staples helps hold the fiberglass in place.

Once the frame is built and the fiberglass positioned, all you have to do is attach the cloth. I used a staple gun. They are fairly light, so they can hang on the wall with a simple screw. There may be times when I’ll want more room sound… then it’s a simple matter to move these somewhere else. Or stack them around a guitar amp, for example… they’re very handy to have around.

I turned the absorber over and stapled cloth to the backside, and it’s finished.

The finished absorber in place

Studio Construction is Finished

I’m happy to report that the heavy construction work on my studio is complete. All the drywall has been hung, sanded and painted (except for a section near the service panel… if I drywall there, then I can’t add other electrical lines, so that part will be left bare for awhile). I laid the last of the flooring a few days ago. The maintenance and engineering dept, aka my workbench, has been built and is ready to work. Now I’ve got to figure out the best place to put all my stuff.

Almost as soon as I got my bench finished, I turned my attention to the mixer. I’ve discovered much more than the “few issues” that I was told about when I bought it. The good news is that nearly all the input channels are functional… one channel wasn’t connected, so that was easily corrected, and number 26 has a bad HPF switch and only works when the filter is active. And the power supply does have new capacitors in it.

The bad news is the master section has got a number of very mysterious problems, with no obvious or easily traceable causes. I think the best course of action here is to send it off to Creation Audio Labs in Nashville to see if they can sort it out. I expect to be sending them a lot of work over the next few months, but I plan to break it up into installments and have them do the work as I can afford it.

The next job on my work list will be to build a cabinet to house the mixer and equipment racks for the outboard gear. I’ve designed a desk that I can build for about $150 or so, it’s just a matter of getting the plywood and slicing it up.

Lots of other finish work remains… installing double glass in the window & trimming that out, treating the door for sound isolation, etc. I expect that to take awhile yet. And I’ll need to buy an air conditioner before the heat of the summer starts up in earnest. But it’s very nearly a useable space right now, which is an enjoyable feeling.

Update: By replacing a voltage regulator in the power supply, I was able to correct a mysterious problem with the LED meters where it would only illuminate in segments of five LEDs… as the signal increased, the lower five LEDs would go dark while the next segment lit up. Very odd. Channel 26 was repaired with a copious squirt of contact cleaner. Next on the list is a rather large order for capacitors from Mouser… there’s room on the boards to increase the voltage and temperature rating.