Circular Solutions
Connections Magazine - May, 1999

The Roundhouse at the University of NSW in eastern Sydney was a notorious venue with atrocious acoustics. Many readers have worked or been there, and never has reinforced audio been satisfactory.

Now an Installed Meyer P.A. system has overcome the inherent problems of a circular room with a domed roof, thanks to the addition of acoustic baffles and accurate design.

Peter Knowland's PKA Acoustic Consulting were engaged by venue operators, the Students’ Union, to clean up the room. The design brief, according to audio systems consultant Adam Townsend, was to improve room acoustics and provide a sound system suitable for speech.

PKA went back with a nice Bose Panaray design, only to discover the room P.A. requirements had expanded somewhat. Dance parties and live sound reinforcement were to be run through the P.A. - so a new design was required.

The room had already been acoustically analyzed on Bose's Modeller software, so Townsend ran some calculations and came up with a system philosophy that would deliver the SPL that mainstream dance music requires. After consultation with the Union a decision was made and the Meyer system was finalized and documented.

To fix the room acoustics, which were characterized by horrible focused reflections, a series of vertical and horizontal baffles were designed, covered in mini orb perforated foil and filled with fiberglass insulation. These catch incidental sound reflections on the way to the top of the dome. Those that get there get treated on the way back again. The shape of the baffles was improved by the architect, and they are a visually interesting addition to the room.

The sound system design is unusual in that four subwoofers are flown under the dome pointing directly down. These are Meyer PSW-6 self amplified units, which offer a cardioid dispersion. This is unusual for a subwoofer, which generally projects bass in an omni-directional or uncontrolled manner. The semi directional ability of the PSW-6 assists in getting the low frequency energy to where it is desired, on the dance floor.

To fly these cabinets face down, rigging consultant Ian Messner worked with Meyer Sound to ensure internal cabinet bracing would support the massive 210 kg weight of each unit, because although fitted with flying hardware, the hanging design of any flown loudspeaker usually allows for vertical flying with the box facing forward and down - not for the box to be flown facing directly down. Messner added some reinforcement before signing off the rigging.

Six Meyer UPA-IP self powered speakers are flown in a ring facing outwards from the middle of the dance floor with another two facing down onto the centre of the floor itself. The result is a system which caters to upwards of 1,500 people and can deliver in excess of 130dB(A) on the floor; claims Adam Townsend. (Of course the system has been limited so this will not occur). This disperses the main audio program 360 degrees outwards, to the edges of the circular venue. Because the Roundhouse has some under balcony areas, extra UPA 1P's are flown out there too, and run on a time delay so they deliver sound at the same time instant as the main circular array.

Additional audio zones are located in the bar area and arcade room as well as an upstairs chill-out bar, well away from the circular part of the venue, but still visible from the general venue.

The bar can be a stand alone DJ system incorporating its own DJ booth, stage and FOH system, or run on a further delay to form part of the main system. Interestingly the system is also used as a main P.A. for visiting bands, who can set up anywhere in the room on a portable, modular stage. In this mode, a pair of additional UPA-1P’s, and/or a pair of CQ-1's can be set up, one either side of the stage, to provide localization, of the band mix. Then the mix is sent to the circular array, with the UPA-1P’s facing the stage turned off or running as a foldback send! Adam says the actual result is far better then you may expect - because when standing under the array the distance to the stage speakers and the dance floor fill speakers above, is almost the same - so time coherence is conserved.

To facilitate the switching of the various sources to the various output zones, a Peavey Media Matrix X-frame is used. This mini version of Media Matrix allows up to eight button activated presets, each of which can allow almost any signal processing necessary.

The audio system is controlled from the main DJ booth, where a 24 channel Allen & Heath GL,2200 mixer is situated for live bands. The system also consists of three Meyer CQ-1's, two Meyer UM-100P wedges and two space UPA-1P’s which can be used on any of the four foldback sends from the mixer. A full complement of Beyer microphones as well as a complete 12 channel portable system complete the audio provisions of the project.

When the system design was finalized, the Union put the installation out to tender - with a very short timeframe of under a month. The winning contractor was G.U.E.T., who by chance had their ‘A team’ of installers In NSW at the time. Iain Everington from G.U.E.T. says that the firm was able to install and have Adam Townsend commission the system within four weeks of winning the tender.

The overall cost of the new system, including some lighting was over A$600,000.