The CEA2010 max burst output is designed to give you an idea of a subwoofers maximum output that will sound clean. So whether the distortion shows 4% or 14%...if it passes, it will sound clean. A dB in either direction will usually drastically affect distortion. So it is just a way to compare max clean output capabilities...you won't be able to tell the difference in sound until distortion surpasses the test limits.
As far as which sub to buy, purchase the one that meets your output needs, gives you the extension you want, is the size you want, the price you want, the looks you want, from the company you like, with the warranty you want. For some, cost is no object and they want the prettiest sub in the smallest package even if its performance is less than a sub that is half the price but is too large or does not have as nice of a finish. Maximum clean output capability is simply one of the performance metrics on which to base your purchase decision. For me, maximum clean output down to 16 Hz within my size and budget constraints were my deciding factors, along with warranty and perceived company credibility/stability.
You probably would not want to buy a sub with 1% distortion at 20 Hz if its max output was 90 dB. The sub with 10% distortion and 110 dB at 20 Hz, will probably have 1% distortion while producing SPL's of 108 dB...or you could get 15 or 20 of the other sub to match the output.
Last edited by bear123; 06-18-2014 at 08:03 PM.