Originally Posted by CZ Eddie
Good info, guys. Thanks!
So if I plug in a couple of different subwoofers and tune them both to 18hz and adjust the box size so each has as flat a response in WinISD as possible.... and I see that one is an average of 3db down in response from the other speaker from 10-40hz, would that be considered a "drastic difference"?
Or would I need to take into account the higher output speaker possibly having more distortion, being say, 27 mm x-max vs. the lower output being 17 mm x-max?
3dB advantage, across an entire range of 10-40Hz, is fairly significant. That means the more efficient system is giving you the same performance with 100 watts input as the other is using 200 watts input. That said, if you did as you suggest, and adjusted them to both have as flat a response as possible, you won't see a 3dB different from 10-40Hz, unless one of them isn't a subwoofer! You can see different -3dB points, and so below those, there will be disparities. Now, I'm talking strictly about the top graph in WinISD Pro, Transfer Function Magnitude. When you use different graphs such as SPL or Maximum power, you may see greater differences.
A higher output speaker won't necessarily have more distortion than a lower output speaker. If both are operating in the linear range of their motors, distortion should be similar. Now that doesn't take into account various technologies such as shorting rings around the pole piece, or more advanced distortion reduction motors, such as the XBL^2 from Adire Audio. A high output XBL^2 motor can and certainly will have considerably less distortion than a run-of-the mill woofer using conventional construction and only 1/3 the linear throw.
All else equal, distortion does go up with increasing excursion. But when it comes to woofers these days, things are rarely ever equal.