Acoustic Sciences Corporation, recently added a new product to their expansive line of acoustic treatment solutions. It’s called the IsoThermal TubeTrap and, according to the company, it delivers twice the bass absorption of an equivalent-sized TubeTrap between 30 Hz and 250 Hz.
By eliminating the thermal component of acoustic pressure, the IsoThermal TubeTrap has an effectively 40% larger internal volume below 70 Hz, which literally doubles its absorbing power while retaining all of the other familiar sonic characteristics of the TubeTrap.
As Art Noxon, Founder and President of ASC and inventor of the original TubeTrap and the new IsoThermal TubeTrap explains, “In any listening environment, the rear wall bounce creates the most bothersome of LF low frequency problems, the phase-cancel effect, aka known in hifi as a “suck-out”. If someone has an 8dB hifi suck-out at 49 Hz, they usually get tired of hearing the same note drop out of double bass riffs, the wall bounce that wipes out a speaker’s frequency response. When the timing of the
rear wall bounce is just right, the incoming wave gets cancelled by the outgoing wave. The frequency this happens at (Fx) is 282 ÷ D where D is the distance between the listener and the rear wall. If the reflection is just as strong as the direct, then the phase cancel effect is 100% and the sound level drops to zero. If the reflection is not quite as strong, then the phase cancel effect is not quite 100% and some sound is heard.”
“It happens at Mach 1, the speed of sound,” says Art Noxon. “We only have a split second to minimize the phase add/cancel effects of the rear wall bounce. The direct signal pulse rushes past your ears, impacts the rear wall and springs back upstream to interfere with direct signal at your listening position.”
ASC developed the IsoThermal TubeTrap to be well suited for aggressively managing typical hifi rear wall bounce phase-cancel
effects. LF absorption is doubled, while retaining all the familiar absorption and diffusion properties of the Standard TubeTrap. The 16”x4’ IsoThermal TubeTrap controls rear walls out to 8’. Larger traps go to lower frequencies.
How does this thermal component work? When you compress gas, it heats up. Expand it, and it cools down. Over time the gas returns to room temperature and the 40% over pressure due to heat disappears. ASC laces the entire air cavity inside the TubeTrap with micron sized fibers which are only a few dozen microns apart. With solid surfaces so close to the gas molecules, the gas returns to room temperature very quickly, well within the amount of compression or expansion time of LF sound waves.
The separation of fine fibers is controlled to provide the proper isothermal efficiency crossover such that deep LF absorption is enhanced without changing the familiar upper range acoustics of the TubeTrap
Together with the new IsoThermal TubeTraps, ASC will display various other products throughout T.H.E. Show in Newport at its booth in the Ballroom (M20). Visitors may sign up for a raffle to win a copy of the ASC MATT & Acoustic Test CD that offers a detailed analysis of the strengths and weaknesses of any listening room or home theater.