The two new rooms were added on to one of the existing buildings at the CIM,with the recital hall on the front and the control room on the back. "Thenew control room was designed and built from the ground up to beacoustically precise," says Egre. "We didn't have to try and fit a squarepeg into a round hole, so we were able to avoid some of the more commonpitfalls of re-fitting an existing space. The institute was very supportiveto both Peter and me on such important issues as room dimensions and ceilingheight."
Accordingto D'Antonio, "The first challenge was to orient the room in the availablespace in order to provide a symmetrical listening environment. Followingthis, we utilised our Room Sizer program to determine the optimaldimensional ratios for uniform modal response."
A number of RPG acoustical products were utilised in the design in order tominimise reflections, add absorption in specific areas, and diffusewavefronts in others. Particular attention was paid to controlling thelow-frequency response of the room. However, as D'Antonio points out, "Wealso had to take into account the fact that it is an educational space andneeds to accommodate more people than a typical control room. This meantthat we had to be very sensitive to the amount of real estate we used forlow-frequency control."
According to D'Antonio, "Every approach that is currently known has beenapplied to this control room with the goal of an extended and flatlow-frequency response."
For the CIM multi-purpose control room, the ATC SCM150 ASL speakers were setup in a surround configuration. According to Egre, "When we conceived thisas the ideal room, we felt that ATC would be an important part of that. Notonly are the speakers excellent, we have received outstanding support fromATC."
The ATC SCM150 ASL loudspeaker is an active three-way system incorporatingan ATC designed and built 15-inch Super Linear (SL) woofer, an ATC designand built three-inch mid dome, wave guide loaded, plus a one-inch high powerwave guide loaded dome tweeter. The drivers are powered with ATC's ownproprietary amplifier package with 200WRMS for the lows, 100WRMS for themids and 50WRMS for the highs all in one package installed inside thespeaker.
The ATC SCM0.1/15 ASL subwoofer incorporates a 1000WRMS-driven proprietary 15-inch ATC SLdriver. The woofer is floor loaded to provide ideal coupling with any room.The ATC electronics/power-pack offers selectable low-pass filters at 2kHz,180Hz, 120Hz, 90Hz, 70Hz and 50Hz plus a phase invert switch. The ATC subsystem is flat to 28Hz.
(Chris Henry)
