Do-it-Yourself Acoustical Treatment: How to build a gobo and why would you want to?
By Tim Dittmar
Acoustical treatment involves making a room sound better. Generally, this can be achieved much more cheaply than completely isolating a room. Acoustical treatments include bass traps, diffusers, Auralex, or other wall foams. These treatments may involve minor construction, but generally not to the degree of soundproofing a studio. There are many do-it-yourself (DIY) methods and resources. Below is an example of a DIY method.
How to Build a Gobo
A go-between, also known as a gobo, is a great mobile way to control sound. It can be used to help isolate an instrument or lessen the reflections and reverberation of a space. I often place a gobo in front of an amplifier or kick drum to isolate and absorb the sound. Gobos are also effective if placed around a drum kit, especially if they are being played in a “live” space such as a kitchen or on a tiled floor. This will tighten up the sound and minimize reflections.
In order to build a gobo, you will need the following items:
1. R11/R13 wall insulation or Owens Corning 703
2. Jute or polyester material
3. 1″−2.5″ wood screws
4. Stapler or staple gun
5. Utility knife
7. Philips screw driver, but preferably a drill
9. 1 × 2, 2 × 2, 1 × 4 wood
10. Two small washers
How to build a gobo:
1. Build the frame to the desired size.
2. Cover one side with the jute, burlap, or other material by stapling to the frame.
3. Put the insulation inside.
4. Enclose insulation with material and staple to frame.
5. Finish off with additional framing/trim if desired.
6. Attach feet with a single screw and washer. Don’t tighten the feet too much, allowing the feet to swivel.
You can put plywood or masonite on one side for a more versatile gobo. One side will be hard and reflective and the other soft and absorptive. The plywood or masonite will absorb some of the lower frequencies.
You can also use a mic stand with a boom arm and acoustic blanket for a quick, mobile gobo. This is a great way to quiet down a drum kit or tighten up an amp or vocal recording. Fold the mic stand into a “T” and drape the blanket over it. Easy and fast to set up and to tear down. Many hardware stores and moving companies sell quilted packing or acoustic blankets. They are also available at companies that carry acoustical treatments.
The above is an excerpt from Audio Engineering 101 by Tim Dittmar.
Tim Dittmar is a musician, recording and live sound engineer, producer, songwriter, and professor. Tim began his professional recording career in 1987 at Cedar Creek Recording studio in Austin, Texas. Before locating to Austin, Tim received an Associate in Arts in Radio/TV Production from Del Mar Junior College. He then spent much of the nineties touring with a punk group, recording bands, and running live sound on the infamous 6th street at various venues. He was hired in 2000 as a professor and full-time faculty member at Austin Community College where he currently teaches Audio Engineering I, Audio Engineering IV, and the Special Projects class. Tim heads up the Technical side of Commercial Music Management at the college. He has also been a returning lecturer at the University of Texas teaching Audio Production and Audio for Picture. Tim has worked in numerous studios in Austin, Los Angeles and Chicago, compiling over 300 album credits, recording such artists as the Old 97′s, Voxtrot, Dynamite Boy, King Missile and the Murdocks. In 2008 he was invited to moderate a panel at the Tape Op Conference in New Orleans where he spoke on “The State of Audio Education”. At present, he owns and operates Las Olas Recording in Georgetown, Texas. He currently tours and records with his wife in the group Annabella and can also be seen drumming with The Hearts & The Minds, Kristi Rae, and Everything’s Gone Green.