The most familiar method of acoustic treatment is the use of absorptive and diffusive materials to control sound waves within a room. An equally important and often overlooked component of acoustic treatment is structural isolation of the room itself.
Product PointsApplications: studio, broadcast
Key Features: Well-designed custom fittings, easy installation
Prices: MoPad kit- $29.95 GRAMMA – $59.95; HoverDeck – $199
Contact: Auralex Acoustics at 1-800-95WEDGE, Web Site
Physically decoupling the room’s structural elements from each other and the outside world – usually with dense, flexible rubber – allows individual elements to absorb vibrations without passing them on adjacent surfaces.
Structural vibration and resonance also occurs between proximate objects within a room, potentially undermining otherwise controlled acoustics. Auralex Acoustics, maker of a wide range of professional acoustic products, recently introduced three items designed to easily and effectively isolate a sound source from its immediate environment.
The Auralex MoPad kit ($29.95) is a foam wedge system designed to decouple studio monitors from that on which they rest.
The system consists of four 12-inch x 4-inch monitor isolation pads (two per speaker) and four adjustment wedges, allowing the monitors to sit flat or angled ± 4 or 8 degrees. The MoPads can accommodate typical close or midfield monitors weighing 100 pounds or less.
As I toted the MoPads from studio to studio for evaluation, I was impressed by the range of audible improvements realized. By decoupling the monitors from other objects, speakers are free to perform as originally designed. In most cases, speakers immediately sounded better. The most common improvement was a tighter, more focused bass response.
In a few cases, the lack of coupled resonating objects resulted in an thinner sound. Here, the MoPads proved to be a valuable troubleshooting device, indicating a problem in speaker choice and/or the acoustical treatment of the room.
In one instance, the change was dramatic enough – far less bass and low mids – for the listener to dismiss the MoPads. This indicated (among other things) that the expensive custom workstation desk on which his monitors rested, and all other objects contained within, were resonating enough to contribute substantially to the overall sound.
While I don’t want to tell anyone what to do with his or her studio (unless I’m being paid), a listening environment relying on unintentional structural resonance will behave unpredictably. The amount and type of resonance will vary constantly with changes in coupled equipment, dampening (human contact with the desk), program material (the key of a song, for instance) and playback level.
Installing the MoPads on my two sets of closefield monitors and on my home speakers improved the performance of the speakers immediately and/or led me to make positive tweaks in the system. In all cases, the MoPads were an easy-to-implement step towards monitoring accuracy; do not rely on the resonance of others!
GRAMMA and HoverDeck
Auralex also has introduced two products built to isolate larger sound sources from their immediate environment.
The Gig and Recording Amp & Monitor Modulation Attenuator, or GRAMMA, is designed to float instrument combo amps, cabinets, subwoofers, bigger studio monitors and stage monitors.
GRAMMA ($59.95) is a 23-inch x 15-inch x 2.75-inch carpet-covered, 300-pound limit platform supported by two blocks of high-density PlatFoam. A carrying handle is mounted underneath, and a block of wedged Studiofoam sits between the PlatFoam strips to prevent self-resonance.
Like the MoPads, using the GRAMMA in a variety of situations yielded a tighter, more controlled sound. Both live and recording setups benefited from the isolation, allowing each speaker cabinet to sing without an uninvited choir of resonating freeloaders. Equally impressive, masking and muddying rumble caused by vibrations transferring to proximate mic stands was greatly reduced.
The Papa Bear of Auralex’s new decoupling products is the HoverDeck kit – basically a GRAMMA on steroids. This is a DIY kit built by purchasing a box of 24 2-inch x 4-inch x 4-foot strips of Auralex high-density PlatFoam ($199 per box). The PlatFoam is used to support an isolated 8-foot x 8-foot riser for use with drums, percussion or any other items. The kit recommends carpet-covered MDF board (though plywood can be used) for the actual deck of the riser. Auralex Tubetak adhesive and detailed instructions are included with the easy-to-build kit.
I built a 12-foot x 10-foot triangle-shaped riser to fit perfectly near the corner of my room. I used MDF board for the platform and an inexpensive WalMart faux-Oriental rug for the non-reflective/non-slip surface. The HoverDeck works as well as the MoPads and GRAMMA in reducing rumble and cleaning up the tone of the sound source. I have been using it with great success to record everything from vocals and acoustic guitar to bass amps and percussion; an instant floating floor with infinite uses.
With the introduction of these easy-to-implement Auralex decoupling products, immediate and effective acoustic improvement is available to many home and professional studios. Though not quite a substitute for full-on floating construction, for those who cannot build from the ground up, the decoupling cavalry has arrived.
Westlake LCW8.1, Mackie HR824, Yamaha NS10m, Meyer HD-1 studio monitors; Hafler P3000 power amplifiers; Ampeg SVT Bass rig; Roland JC-120, Fender CyberTwin and Ampeg J-12R guitar amps; Zaolla Silverline cables.