Subs?

I say more the merrier. They add depth to my system. I started with one KEF R400B, Each sub has 2x10" speakers and a 200 watt internal amp. That was good, so I added a second of the same. I cross over at 40 hz. They are very adjustable, and you really don't know they're on, until you turn them off. My main speakers are Sonus Faber Cremona Ms. I'm contemplating adding a third. 

2 subs are better than one in most rooms and probably in your room based on your description.  I started with one SVS SB1000 Pro.  It sounded good.  I got a second one and it sounds even better.  

1st you have to decide your on your priorities… Do you want Music Bass or Movie Bass ??? The Experience is totally different with each… So what is your main listening going to be ?

I went from (1) SVS Front Firing 12”er to (2) REL 8” Down Firing T-5X’s. The SVS was ok for movies but for music it just didn’t cut it. Was it only because I had one ? I couldn’t tell ya but the 2 RELS are much more musical and dialed in so easily. I found being they had smaller drivers the response was much faster and worked better in my smaller room of 12’ x 12’. Being a smaller driver they have a lot less air to move. I have them dialed in at 45.25hz and volume level as one noted before at “ A Whisper” and couldn’t be happier. No Localization !!!! The secret to a sub’s successful integration into your set up is to not know you’ve got subs, but would seriously miss them if they weren’t there. Wanna drive yourself nuts? .. Nothing worse than hearing bass coming from a specific location in your listening room and having multiple subs certainly balances things more evenly.

Being my PreAmp has HT Bypass I do have the RELs attached to my DENON 3700 AVR as well through the AVR’s LFE output to the REL’s “SEPARATE” LFE input.

NOTE: REL’s allow you to have High QUALITY inputs from BOTH

(1) directly from your Audio System’s Amps through the speaker outs sharing the output feed that goes to you speakers and

(2) also has SEPERATE LFE inputs for an LFE signal from an AVR with the ability to Automatically switch incoming signals according to the input signal being feed to it.

The bass response for movies is great but music is my key objective and I couldn’t be happier than I am with the (2) RELs

JL audio is a big pass...build issues. 

Had two JL audio Fathom V2 subs that cost me $10,000 USD. I did not heed advice on here to avoid at all costs. One was broken on arrival and the other sounded terrible despite professional integration with REW, miniDSP etc. Martin Logan’s at 1/3 the price have been flawless. Like others said, friends don’t let friends buy JL.