My experience adding subwoofers to 2 channel

Hello khiak,

     What are the dimensions of your room (length x width x ceiling height)?  What are the brands and model numbers of your subs? 

     You can definitely achieve very good bass response at a single dedicated listening seat with 2 subs. Using the 'room crawl method', described to avanti1960 earlier, in a sequential manner (first sub#1 and then sub#2) is probably the best way to position them.
      In my experience, 2 subs will provide much better bass performance than 1 but in my opinion 4 subs will provide the best bass performance since line array sub configurations are not well suited for small rooms like distributed array sub configurations are. 
     The 4-sub DBA system concept works incredibly well in virtually any room and actually is perceived as making a small room seem like a larger room.
     The key to a DBA system being such an exceptionally high quality bass solution is the use of 4 subs; the brand/model, size, power, price and type (self amplified or passive) are much less important than the fact that there are 4 of them active in the room.  There are also no requirements that all subs are identical and subs of varying driver sizes, power, prices, types and bass extension are viable.
     If you have a smaller room, however, I'm curious why you chose to add 2 subs with large 21" drivers when adding 2 more subs with 12" drivers is more logical and physically suitable?

Tim

Hi Tim,
The room length 18 ft, width 12 ft and height 9 ft. The subs are JL212v1 and 21.0LX Funk Audio.

The main speakers are 7 ft apart and the JL212 sit about 1.5 feet behind the main speakers inner side. The main speakers is 5 ft from the back wall.

The main listening chair is 7ft from both speakers and 12 ft from the front wall.

Three feet behind the main chair are a row of 3 chairs.

A 21.0LX sit on the left wall 3 feet from left main speaker with the driver facing the right wall.

Another 21.0LX sit near the corner of the right wall 9 feet from the right main speaker with the driver facing the left main speaker.

The acoustic of the room is designed by ASC of Seattle.

So much discussion on 4 subs in the room, so I want to hear how 4 subs sounded in my dedicated room which is for 2 channel and home theatre. Why 21 inch driver, I never hear how 21 inch driver sound.

The rest of the wall space are occupy with racks and equipments and tube traps.

There are no other location available for the 2 21.0LX.


I have no idea how to go about to setup/calibrate  the 4 subs optimally.

Any help appreciated. Thanks.

khiak

Hello khiak,

     Those Funk Audio 21.0LX are beautiful subs but they're really meant for a larger room.  If you live in an apartment, your neighbors are going to hate you if you start using those in your room.  If you really want to use those in your room, you'll need to keep them turned to a low volume to work well in a 4-sub DBA.  I currently think the best solution for your room size would be 4 subs with single 12" drivers.  A few more questions:

I'm having trouble looking up the JL 212 V1, is the model# F212 V1?
Do they have single 12" drivers or dual 12" drivers?

Would you be able and willing to return the big Funk Audio subs to achieve better overall bass in your room?

It sounds like your main speakers and rack are along the long 18 ft wall with your listening chair, with 3 seats behind, along the opposite 18 ft wall.  Is this correct?

Are you planning on moving to a bigger place or home soon?

Thanks,
  Tim

Hello Tim,
i have the dual 12” F212v1. I just got the 21.0LX the early this month after waiting 6 months for them. Comparing to the F212v1 which I have for the last 6 years, I like the 21.0LX better as it makes the overall sound more engaging. Big doesn’t have to be loud, the output level gain have to be lowered so they just disappeared into the room like the F212v1.
Unlike the F212v1 which have the variable 360 phase adjustment, the 21.0LX have delay adjustment in ms by the software DSP. My system sound best with only the 21.0LX. With the 4 subs, I think there is a timing issue between them which smear the sound. I have no ideal how to set them to be in phase with each other and the main speakers.
All available space on the left and right wall are racks with the hifi equipments. The back wall are tube traps from floor to ceiling and blue ray cabinets. On the front wall I have the fix screen for the projector, and half tube traps below the screen. Also floor to ceiling tube traps on the corners of the front wall and a cradle mounted center speaker.
I am not planning to move as I am over the 70s, my last hangout. Hahaha.

Hello khiak,

      Well, you have four very high quality subs which you should be able to position and configure into a very high quality 4-sub distributed bass array system for music and ht.  
     I'm willing to assist you in this process but I want to warn you it's going to take some work and trial and error experimenting to properly position and configure the settings. 
     If you'd like me to assist you, I just need to know a few more things before we get started.  It sounds like you have a screen and projector for video setup on the opposite 18 ft walls. So, I need you to confirm this and describe the rest of your audio/video equipment:

1.  All your receivers, amps, preamps,surround sound processors, turntables, cd players, video players and any other hardware you use.
2.  All equipment and storage racks.
3.  The main speakers, center channel and surround speakers you use. 
4.  Any room treatments you currently use such as carpets,bass traps and absorption or diffusor panels.

Tim