Spectral Balance is based on a forthcoming joint standard from InfoComm and AES. It is envisioned to provide an industry-wide specification for sound system performance. Using multiple measurement techniques, including methods to minimize the effect of low frequency room modes, system performance is compared against a range of limits that are defined in the standard. If all of the frequency bands are within the limits, the sound system is said to pass, otherwise it will be marked as “Fail”.
The Spectral Balance module in AudioTools takes its frequency data points from two files, one for the low frequencies, and one for the high frequencies. The crossover point is determined by a formula that uses the room dimensions.
The actual frequency measurements are made in the RTA, SPL Graph, or LARSA module in AudioTools, and the results are chosen from the Settings page in the Spectral Balance module.
The low frequency data is taken by using RTA in Average mode, or SPL Graph, using its Leq feature. The test system is moved around the room, to average the low frequency modes so that a smooth response is measured.
The high frequency data is taken using LARSA, with a 15ms window.
After selecting the two data files, Spectral Balance splices them together at the frequency crossover point, and uses a a best-fit algorithm to determine whether the room is marked Pass or Fail.
Spectral Balance is an in-app purchase, and for proper usage also requires purchasing the LARSA module.