It would surprise me if there was a change in quality of the sub-bass that was audible in an amp designed to operate into those frequencies. I mean everyone seems to obsess over the SQ of sub-woofers and there is so little sound quality in those notes to begin with... cant we obsess over capacitors instead?

 

Funny how that last question fits so well with the tag line in your sig......

 

Im talking about sound quality, Not how loud the speaker can perform.

 

I will need to vote "no" as well because I've never heard the difference in a subwoofer application. The general idea is that you will be out of electrical phase with it's counter part(s) and therefore out of accoustical phase by having one sub playing slightly before the next giving you time correction issues to deal with.
Theory is a wonderful thing to play with in the winter time.

 

We're agreed on the "no" vote, but how do they get out of phase? My understanding is they would be actively filtered and connected to the same mono amp.

 

Phasing issues happen when you run speaker coils in series, just like when you add a coil in series for a low pass filter.

 

the answer is definately "YES".

 

The current will be in phase (shift effect) so how can they be acoustically phase shifted? Which one will lead the other?

Coils exhibit phase shift between voltage and current with voltage leading. Two coils in series will exhibit the same shift as one coil of the summed value. Think of it in this case as one big voice coil. There can be no relative difference.

 

You'll need a stobe light and a camera that can open the shutter very quickly in rapid succession to realize it. One will reach it's maximum before the next because of it being out of phase by 45 degrees. If one gets there before the next, then accoustically, they will be out of sync with each other, therefore making a time delayed sound effect.
You'll see the sub getting the power first to be quicker than the next.
It's the biggest reason that SPL'ers put theirs in parallel.

It's also the reason that the "old timers" are not sticking their necks into this. It's all theory!

 

The question as put, is a single woofer with a dual voice coil being driven by an amplifier capable of driving the impedance's chosen.

I wonder how a high current EMF vs. a low current EMF would alter specifications and measured performance of the amp