Knowing In Advance
The mix volume for the Las Vegas production of Blue Man Group spans from 80 dB to 105 dB (A-weighted). To insure sufficient headroom, the specification for the new PA was established as 108 dBA (RMS) at front of house with a peak output of at least 118 dBA.
Establishing a target before selecting the box count or type helps me make sure the system has enough resources for the content of the show. To me, selecting a specification for output of the PA is the same as selecting a mic for an instrument: knowing in advance the SPL capability of the system means clipping or limiting of the system will not happen.
The coverage target for the theater was +/- 3 dB from front of house in both A-weighted SPL and response. With a long throw of close to 100 feet and a short throw just under 20 feet for a differential of five times from front to back, this venue is very well suited to a line source array. This is just over two doublings of distance; it would be possible to have no more than 6 dB of loss from front to back, and with proper angle selection, less than 6 dB seemed doable without breaking the line into segments.
The combination of coverage and size limitations really dictated that a modular line source array would be the right solution. By segmenting the low-frequency component from the main element, it allows for a reduction in element size and an increase in resolution. To deal with the limited vertical space and coverage demands, it was a far better solution than a large-format enclosure with a 12- or 15-inch LF driver.
Blue Man Group extending tubes (and boundries).
Further, having already successfully deployed KARA in Australia, I knew it would be a good fit. It was more than capable of delivering the dynamic range and response the show requires, and being smaller than the previous system, it would not be limited physically in the space.
A nice byproduct of the smaller form factor is that I was able to move the arrays further offstage and rotate them more toward center, keeping reflections off the architecture and allowing for a larger stereo field.
Using L-Acoustics SOUNDVISION modeling software, I determined that 15 per side of KARAi elements would be able to achieve the SPL target and almost perfectly meet the coverage goals.
This approach reduced the overall vertical size of the arrays, allowing them to be positioned slightly lower overall to cover almost every row in the theater with minimal shadowing from scenic and architectural elements. It also meant a reduced need for fills.
With the limited time for the transition, it was essential that all variables were considered in advance of the install. The software modeling also helped me ease the concerns of the production team.