[Otto]

Yep, I agree with the others that think it's just a cool name to use. The implication is that it's such a great sub that others will measure their offerings by it. Any such "reference" sub may or may not be able to play X dB of pink noise at Y% distortion, etc., etc., but there's no rules to this, so associating the "reference" name with any type of performance would be impossible.

Thats pretty much it.