Your experience of moving to two subs

One man's datapoint.

Hsu VTF2 Mark IV subwoofer. (Out of production.)

In TV system: one sub off to one side opposite main speakers but not in corner..

In audio system: four subs behind main speakers.

No difference between one sub and four. 

Subs make your main speakers sound better because they don't have to work as hard with the sub handling low bass duties.

This Hsu sub has two ports which I have plugged with the foam plugs that come with the sub. Less bass but tighter compared to leaving the ports open.

https://youtu.be/_7ZGLrOpCQo

https://youtu.be/xUMDlpVu98w

One sub is fine, two are always better. More is better in the case of subs. As others have said, multiples really can better fill out the sound stage and give a really full and balanced experience. One huge fallacy is that subs are for movies and not music. That is an opinion that is completely baseless, proven wrong consistently, and only held by insane "2-channel only" types and possibly deaf sheep herders.

What sounds good to me is what’s optimal in my system.

For me, the saying is,

What sounded good to me is what was optimal in my system, until I learned about how to improve it.

While I don’t want to be on an endless hamster wheel, this is a hobby for me precisely because I am striving to see if I can make things better.

I have been able to improve the sound in the past, and that motivates me to keep trying -- because it’s fun, not because I have a "grass is greener" dysfunction.

@dean_palmer said
“That is an opinion that is completely baseless, proven wrong consistently, and only held by insane "2-channel only" types and possibly deaf sheep herders.”

I say….

Thank you making me howl. That is so freakin’ funny!

I completely agree that by seamlessly integrating a sub or two (or four?) the listening experience can be taken to a level that is far more difficult to achieve relying on stereo “mains” alone. With subs added, it won’t be 2-channel anymore, by definition, but it will 110% still sound like it, meaning the sub(s) will not be discernible as a source of sound.

Coincidentally, my goal has always been for the main speakers to be undetectable also. Having 2, 3, 4 boxes in your room, but the illusion that the sound is not originating from them is central to the illusion for me. Speakerless-ness, I call it. If the illusion of speakerless sound is achieved, designations such as 2-channel, 2.1 or 2.2 are, for me, unimportant labels.

Of course the specific qualities of the “speakerless” sound (e.g, tone, dynamics, etc.) one pursues is a matter of personal taste and ever-evolving.