Analyzing An Arena -
Working Quickly with an RTA
By Gregory Miller/ Gold Line
|Sports Arenas are always a challenging acoustical space. Typical metal walls and ceilings with concrete floors and columns make for reverberant spaces. We were recently out in the field with Tom Nicks for set up at the 2003 NBA Finals in the Continental Arena (Meadowlands Sports Complex/NJ). Pop diva Jewel was doing the half time show, and they had been asked to try and optimize the house system for her performance.
||With minimal time to work on the system, a DSP30 RTA provided some quick data. Like most arena's, the Continental suffers from the classic "Boom in the Room". Utilizing pink noise it was apparent that there was substantial acoustical gain from reverberation occurring in the 50Hz region. The solution was to roll off the bottom end of the spectrum below 63Hz. While this would mean that there was less energy for the music at low frequency, the improvement in the mids was dramatic as we were not driving the areas of the spectrum with the longest Rt times. We also commonly see this problem in large churches, and if not corrected the result is what is often referred to as "muddy sound". The long lasting reverberation simply masks over the direct sound.
|The arrays in the Arena were modern PA boxes reasonably arrayed. There were no delay lines, but parametric equalization was available. We used relatively broad filters in the mid-range to correct for octave wide problems, and avoided the temptation to try and fix very narrow problems which were more likely time based. Tom then rolled off the high frequency above 12kHz to avoid the dangers of overdriving high frequency devices, which were already somewhat marginal for the size of the space.
|With this preliminary work done, it was then time to listen to the system. If we had been given more time, we could have done distortion measurements to look for signs that the system was approaching its limits. Needing to work fast, we relied on our ears for tell tale signs of harshness, which would indicate the onset of distortion. We then played some of the tracks which would be used during the show and walked the space. The bottom line, is that our ears correlated well with the data. The vocals were clear in the mix after the roll off of the low end and the moderate boost in the mid-range.
||Given more time, there are many more things that could have been done. Given the time we had, and the system we had to work with, it sounded pretty good. And, if any of you were at the game, we hope you enjoyed it. Always a pleasure to get to work with the guys from the NBA Audio Staff and dB Sound/ Touring Business Group.