Your experience of moving to two subs

Yes group delay matters a lot with subs. group delay and phase are related. The audioholics information is very good.

Many subs are delayed enough they are a full cycle back. The kicker is it can change at different frequencies so you can’t just adjust it out with a simple phase knob. At the lower frequency the cycles are so long (slow) it is less of an issue but still very relevant. It is one of the down side of having all the high tech processing in subs these days. It all takes time even though it is still pretty fast. I personally will not buy a sub unless see the group delay measurement as I feel it is important. In a system where timing can not be corrected (99.9% of 2ch preamps). Think of it as input lag ratings of computer monitors.

@james633 Sounds like why I chose to give up on the parametric EQ section of the amp on my Rythmik sub, soon after buying it. Sounds significantly better and faster to me without applying a specific FR curve.

The argument that convinced me to go with two subwoofers says:

The bass wave is extremely long at the low end of the sub’s output, and the listener cannot tell where it originates.

The sub’s output higher up the spectrum enters the zone where the listener can tell where it originates.

And we want every directional cue we can get for the best soundscape.

Admittedly not much information is ‘lost’ to the listener with only one sub - if any is ’lost’ at all at those frequencies - you’re already down at 28Hz.

It’s a matter of a few percentage points improvement, maybe only 1% or 2%.

For me it was vital improvement.

Bass and drums took on a richer, finer texture, and the soundscape resolved more completely.

But then, my crossover points are in the low thirties and upwards of fifty for Magnepans.

@ditusa The article written by Doug Blackburn exudes confidence and it sounds plausible, but I disagree with a good portion of his assertions due to my experience. "Listen to a subwoofer all by itself for a while. You won’t hear anything vaguely resembling speed coming from that slow, soggy-sounding, plodding subwoofer. It has no detail and no speed whatsoever when heard all by itself."

I’ve done this with different subwoofers and they sound different. The SVS SB2000’s perceived quality of rapidity vs slowness changed significantly when changing its power cable with those of different materials and constructions. I started a discussion thread here about it some time ago.

The way I see it, the audio hobby is really about listening. Some people can detect differences just by listening, so they don’t rely on concepts so much, just like some people who can see clearly at very far distances don’t need corrective lenses. Some people don’t have the ear/brain training/gift/whatever to perceive as acutely, so they rely more on measurementation and abstraction. This is the primary basis for my system building, and the reason I disagree with the author.

I’ll give the other article a read today. I think it’s more up my alley.

I have 2 subs-10" Eminence.  We run these with a Yamaha power amp, commercial.  I have never ran out of power.  I have a Marchand  crossover to make sure the level is right for subs and mains.  The crossover is at 100 Hz.I don't have phase adjustment.  These subs are where they were for 20 years.  I don't know if it would sound better somewhere else.  Recently I removed the crossover and ran the speakers fill range. Not as clear, less bass and transients all were not as good.  Why?  The subs reduce load on main amp and reduce intermodulated distortion.  This causes the mids to be not as clear.  I  have 2 bass traps and 6 first reflection with 3 diffusion panels in rear.  I finally have the system so I can walk around the room and the sound is the same, except no imaging.  I could buy a couple more bass traps, don't cost much.