My experience adding subwoofers to 2 channel

Thanks, Tim for your help 

I have recently added 2 more 21 inches subs to the existing 2 12 inches subs to my main speakers. I find that the system sound more engaging with just the 21 inches subs. Maybe the subs are out of phase with each other. I do not know how to integrate them.

Yes

I have the 12 inches subs for 6 years. The 21 inches subs added this month of May. Room is small so limited choice of placement.

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 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 Tim,
Many thanks for your kind offer to help me in the setup of the 4 subs in my music room. 😃😃😃

After viewing Audiogon forum on getting better bass performance with 4 subwoofers in a room, I decided to give it a try. So I added two 21.0LX to my existing two F212.v1 early this month. Instead of adding another two F212v2, I decided to go for 21 inches woofers as I have never heard the bass from such woofers in my life. I have owned the F212v1 for 6 years but I have to say the bass of 21.0LX is awesome.

I have a fix Stewart movie screen frame 94” X 55” at the front wall about 5 ft behind the tweeter of main speakers. The bottom edge of the screen frame is 27” from the floor. From the left edge of the screen frame to the left wall, there is a ASC full round tube trap from floor to ceiling, similarly on the right edge. From the bottom of the screen frame to the floor, I have half round ASC tube trap horizontally. I have 2 half round ASC tube trap mounted on the ceiling between the 2 corners full round tube trap. There is a set of 3 half round tube traps mounted on the ceiling across the width of the room above the main speakers.
A Revel voice 2 center speaker with mounting pedestal sit in front of the movie screen with the F212v1 at each side. The subs are about 2 ft from the edge of the Center speaker.
The Kharma Exquisite Reference 1E Signature main speakers are 7ft apart and the F212v1 is about 1.5ft behind the main speakers inner side. Between the main speakers are 3 rows of 5 mono amps and preamp power supply. Left row is Goldmund Telos 600 stack on top of each other for left main speaker bi-amps, middle row is Goldmund Telos 600 mounted on the bottom of 2 deck rack for the center speaker. The power supply of the Goldmund Mimesis 22S sit on the top deck of the rack, right most row is Goldmund Telos 600 stack on top of each other for the right main speaker bi-amp.
The Goldmund Mimesis 22S Signature preamp sit on a rack in front of the Rack for the center  speaker power amp. 
On the right wall 1.5 ft away from the right main speaker are 3 rows of 3 deck racks where two Mark Levinson N332 for Revel Embrace surround and Vienna acoustics back speakers, Marantz MM8077 for  four Beale Street ICA6-BB height speakers and two Bose wide speakers. Marantz AV8802A processor, Pioneer DVL-919, Dream Vision Sealer 3, Lexicon RT-10, Phillips BDP9600 and Panasonic DMP-UB900 are located.
On the left wall 1.9 ft from left main speaker, sit the 21.0LX follow by a rack with 2 deck for the Reimyo CDP-777 and DAP-999EX and finally the door to the room.
On the corners of the back wall are full round ASC tube traps from floor to ceiling with a 70”X16” wall mounted Blueray cabinets on their side and 3 columns floor to ceiling full round ASC tube traps between them.
The right and left walls above the rack height are space with ASC sound planks. At the wall just beside the main speakers are custom wall mounted reflective towers.
The main listening chair is 7ft from the main speaker and 12ft from the front wall.
The JVC RS-65U projector is mounted to the ceiling directly above the main listening chair.
Hope all these info are helpful. I wish I can send you photos which are much better.

😃 Thanks 
khiak

Hello Tim,
In 2000, I bought a pair of MBL101D Radialstrahier speakers. I enjoy listening to my music very loud around 85dB to 90dB, so you can imagine in a room 18’X12’X9’ without acoustic treatment, everything sound bad especially the bass. So I got ASC Mr Art Noxon from Seattle to design the acoustic for the room.

The floor is concrete overlay with 3” wide 0.75” thick 48” Long teakwood of various length

Hello Tim, 
Is there a way I can send you a video clip of the room? 

Hello Tim,
 “ I just sent you a personal message. You should see a 'dialogue bubble' icon on the upper-right side of your screen, next to the 'shopping cart' icon. Just click on that and my pm should show. Click on my pm and I think you can hit reply and attach your video clip before sending.
 I'll re-post on this thread once I receive it.”

i do do not know where to locate ‘dialogue bubble ‘ icon.
khiak

Hello Tim,
I still do not know how to send the video to you. As so I am not savvy, please take me on a step by step. Thank you.