Your input please: Using sub on 2 channel amp

I am using JM Lab Cobalt 820 on my tube amp & pre-amp. Sometimes I am missing a little bit of bass coming from my main speakers. Is it possible to add up subwoofer on my 2 channel system?

I am considering Sunfire subs which is around 1100. You think this could add up to what I am missing without degrading musical excitement?

Your comment and suggestion please.
Two subs makes good sense in some cases, but in your situation you'd do far better to spend that money on just one really good musical sub. I'd recommend Vandersteen 2Wq or Rel Strata II/III, both of which use the signal out of your amp, for the most seamless blend. Either of these subs will competently fill in the low end, but will never smack of sub-bass. I'd way rather have one of these, than two Sunfires any day.
I second Jimmdavis, I added a Rel Strata III to a pair of ATC SCM 12 recently and could not be happier. I always worried that adding a sub would take away from the main speakers in some way, but with the REL you can't tell it is there except when there is deep bass, it feels like it's part of your main speakers. Highly recommended and so easy to set up right.
Yes it is more than possible it,s proven. Just make sure you choose a MUSICAL SUB and not a home theater sub. Rel's are very musical, totem, older NHT's, and others. Cheers
Assuming yours is a music only system, you won't need much of a sub -- most music just doesn't have that much bass.

A good so-called HT sub will be cleaner, but you probably won't need it. Depends on the size of your room.

Due to the use of first order crossovers, Vandersteen almost requires using two subs. That was Richard's comment to me years ago.

Sunfire subs don't measure very well due to their small enclosures. They may do OK for music -- based on your room size.

It doesn't matter whether you use line level or speaker level connections. You can make either work. Line level will let you use an EQ. Level matching with the main speakers is very important.
Go with REL. If you use speaker level it will add bass without changing the sound of your main speakers. Will improve the sound even if there is not a lot of bass present.
REL, Velodyne, JL Audio are all excellent choice for musical subwoofers. I have 15 x 20 room with Focal Electra fronts that can go down to 30Hz. The bass response is already pretty good. But when I added DD12 to the system, the bass response went up to the next level. You don't need to listen to bass heavy music. The subwoofer adds nice ambiance to any recording from small band jazz to symphonies.
ML Depth sub along with my 3.6 maggies sound great. Check out the ML line of subs while you are at it.
Lots of good suggestions above. Personally, and as a 2-channel, music-only guy, I can't imagine doing without my recently acquired REL Stentor II.
Forget the sub and look at amp/speaker combo. I've got a tube system with Dynaudio Special 25s (88db pigs). I bought a Dynaudio Sub250 to fill in the bottom when I watch movies; I can't remember the last time I turned it on. Try working on your speaker placement, it can make all the difference in the world. Also don't discount your speaker cables... (Oh and by the way I'm loving my VTL ST-150.)
For me, the great advantage of subs is the ability to add EQ to the bass. The best speakers in the world may measure beautifully from 20 to 20K in an anechoic chamber, but you don't want to see how they meausre below 150hz in your room. Trust me, it ain't likely to look very pretty. While EQ may violate some audiophile golden rules, bass only EQ strikes me as a great way to have (most of) your cake and eat it, too.

Bob's comments about the bass content of music are generally true, which means that - IMHO, IMHO, IMHO, - your choice of sub is probably less critical than proper integration and EQ. I use a Velodyne SMS-1 sub controller ($500 street price) and it works great! You can also use an NHT x-over ($300) if you don't want the Velo's digital x-over in your main signal path. If you go that route, you can use the Velo for room analysis and EQ or you might prefer the new Audyssey bass EQ box from SVS for that task.

Good Luck


PS While sub choice may not be the most important factor in getting better deep bass, I'd note that the SVS subs do appear (from test results at to represent great value.
I really appreciate all your input here. It makes me wonder what's my next move. But for sure base from your input I will add up Subs on my main. Thanks again.