Hi all (I'm reposting this for those who may not have seen it the first time)
For those who haven't heard yet...ALMA and CEA have introduced a new method to gauge subwoofer performance. This is very good news indeed...as it will standardize things a bit and really levels the playing field for all manufacturers. A nice sidebar is that their test procedures(and the reasoning for them) closely parallel the methods of Nousaine and Mullen (and SVS) in determining the "clean" output capabilities of a subwoofer. The new 2010 standard does raise the standard 10% THD limit (in the deepest bass)...but this isn't a significant difference. Once you reach 10%, it (almost always) only takes another dB or two to raise the distortion levels to 25-35%(and often much higher). So if a subwoofer hits 100dB/20hz/10% THD...pushing it to 111-112dB will typically give you >30%. They test the subwoofer at 20,25,31,40,50,63hz. They then "score" it on "ultra low bass" and "low bass". The ultra low bass is the average of 20,25,31hz. The low bass is the average of 40,50,63hz. For each subwoofer, they will give you two "scores"...the Ultra low bass score...and the low bass score.
It will be a while before we get to see a large number of "scores" for subwoofers put through their paces in the new 2010 test...but here is how two of the most popular SVS models fair in our methods...which (imo) are close enough to the 2010 method to offer fair insight into what we can expect when these models are tested(using the new 2010 standard)
The differences are...
1)we currently use sine waves(the 2010 method specs a tone "burst"). In my experiences the tone burst method generally gives you a higher "score"..but not significantly so.
2)we measure output capabilities using 1/3/5/10/20% THD limits. The figures I'm listing here are with the 10% limit. Again, the 2010 method(which allows 25-35% THD down low) would give us another dB or so(on average)
3)we measure at 2m(ground plane). The 2010 method will convert everything to a "1m ground plane standard" So you would have to add 6dB to our readings to convert them to a 1m distance.
Based on these 3 differences. I have added approximately 8dB to all of our data. 1dB for #1, 1dB for #2m, and 6dB for #3. This may be a little conservative...but it should still be "in the ballpark" as they say..
Ultra Low Bass = 117.23
Low Bass = 126.13
Ultra Low Bass = 107.76
Low Bass = 112.97
Remember, these are estimates onlybut I think they will eventually prove to be surprisingly close. Since SVS has become the target for other manufacturers to shoot for with their dream productslet's hope they have something that will approach CEA scores of 117/126 at $1199 and 108/113 at $429 for the consumersomeday..
If they cannot...I'm sure we will all hear how excessive distortion is something to strive for..