Best multi-purpose subwoofer

guhlamr and gillatgh,

While your room (22x22x8) is larger than gillatgh’s room (15x22x8) and you’re both using only a single high quality sub, you’ll both find that you can optimize bass response at a single position (your chosen listening position) in your rooms provided the sub is properly positioned within the room in relation to your listening position. I detailed the procedure for properly locating a single sub in my last post.


The compromise of using only 1 sub in a room is that bass response will be poor at numerous other locations in the room. This will be obvious by just walking around the room after optimizing the bass at your listening seat. You’ll notice that at various spots in the room the bass will sound exaggerated, attenuated and even nonexistent. These spots of poor bass are the result of ’Bass Modes’ existing at these spots in the room.
Bass modes occur because bass sound waves launched from a sub are very long (a 30Hz sound wave is 37.66 ft long, a 20Hz wave is 56.5 ft long) and these long waves continue to reflect or bounce off room boundaries (walls, ceiling and floor) until they run out of energy.
The points where these reflected bass sound waves meet or collide are called bass modes. When 2 sound waves reinforce each other, the bass will be perceived as exaggerated. When 2 sound waves meet at various angles, the bass is perceived as attenuated and when 2 sound waves meet or collide head on, the bass is perceived as totally absent since the 2 waves cancelled each other out resulting in what is termed a ’Standing Wave’.
As I’ve stated before, the only currently known method of attaining very good bass response throughout an entire room is to deploy what is called a ’Distributed Bass Array System’. The DBA system is a scientifically proven method (developed by 2 doctors of acoustical engineering, Earl Geddes and Floyd O’Toole) that consists of 4 subs strategically positioned in a room that is exceptionally effective in significantly reducing the number of bass modes in any given room.
An additional benefit of the JL f112 sub is that it’s fairly simple to add additional JL subs if you ever wanted to. The existing sub is termed the ’Master’ and an additional JL sub is called a ’Slave’. Only a single cable is required for connecting the slave to the master. Multiple slave subs can be connected connecting them with a single cable in a daisy chain method and the master recognizes all attached subs as a single bass system.
So, you both currently have very good bass response at your listening position and have the option to incrementally improve that bass response by adding properly positioned subs. If you decide to deploy a DBA, you’ll attain state of the art bass response throughout your entire room and likely be able to charge admission for music or ht.


Enjoy,
Tim
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@ghulamr --

I believe you made a sensible choice with the JL Audio F112. Never heard/felt it, but from what I’ve read it’s a very powerful and accurate sub that extends below 20Hz, so something along the lines of REL-territory musicality with the added bonus of brute force and infrasonic capabilities, the latter of which adds another dimension/experience layer to Blu-ray/UHD films. I used a single SVS SB16-Ultra for a year and a half, a sub I believe compares in performance to the F112 rather closely, and placed between my main speakers it integrated very well for both music and Home Theater duties. I had it low-passed at 61-62Hz/24dB with the mains running full range.

As of late though I’ve converted to a pair of (tapped horn) subs, and experimenting with dual placement has come up with some interesting findings. One option (in variations) has been to have one sub between the main speakers and the other behind the listening position against the rear wall (optionally in a corner), configured in mono with a cross-over to the mains somewhere between 80-100Hz - a rather successful setting with good pressurization and fairly flat/smooth response.

Placing them instead along the side walls fed with a stereo signal (digital sources maintain stereo all the way down in the lowest bass, insofar they’re mixed in stereo, whereas LP’s are monaural below 100Hz regardless) in a symmetrical configuration to the mains has the bass from the subs "latch on" to the mains in a distinctly more natural and very seamless fashion compared to the front/rear option and single front/center placed SVS, not least making for an even more coherent presentation. I think the primary factor to be aware of here is placing dual subs symmetrically in relation to the main speakers (making phase/delay adjustment much easier, along with gain), and even having a true stereo signal for better ambient reproduction. The latter aspect here may be debated due to bass being less directional below some 80Hz, and while my subs are crossed between 80-100Hz/48dB (not yet settled) to be more directionally "visible," I find the bass-being-omnidirectional claim too categorial in not factoring in the importance of ambient information aided via a stereo signal, below 80Hz as well.

So, do consider a second F112 in your setup, for several reasons; you’ll have ~6dB more headroom as well and double the air radiation area. In the meantime enjoy your new acquisition and integrating it with your mains and acoustics.

phusis:
"I find the bass-being-omnidirectional claim too categorial in not factoring in the importance of ambient information aided via a stereo signal, below 80Hz as well."

Hello phusis,

I partially agree with your statement but, based on my experience, I think you have the cause and effect reversed. I know this is a subtle difference but I believe it’s important so I’ll do my best to explain.
First, I believe bass below about 80Hz is omnidirectional (that is, humans cannot perceive exactly where the bass sound is coming from.) Whether you configure 2 subs in a stereo or mono configuration, there is no ambient information existing on bass from about 80Hz and lower.
However, musical signals at or above about 80Hz are directional (that is, humans can perceive exactly where these sounds are coming from.)
I think the critical factor in determining exactly where bass sounds are coming from are the harmonics of the bass notes. For example, a fundamental bass note at 40Hz will produce harmonics at 80, 120, 160, 200, etc. Hz. Once these harmonics exceed about 80Hz, humans can perceive exactly where the sound is coming from. At this point, I think our brains take over and associate the multiple harmonics with the 40Hz fundamental note and the location it’s coming from.
So, I believe there is important bass ambient information aided via a stereo signal but none below 80Hz. Fundamental bass notes below about 80Hz are omnidirectional but the bass note’s fundamentals above about 80Hz are directional and are clues to where the fundamental bass note is coming from.

I believe the above based on my configuration and setup of my own system. I think the bass is the hardest to get right in any room/system so I do that first.

I use 4 subs (each is 28"hx12"dx14"w and weighs 40 lbs) all run in mono and powered by a separate 1K watt class AB amp with the cutoff frequency set at 50Hz. My room is 23’x16’x8’. My hdtv, system rack and components are located and centered along the front 16’ wall. My listening chair is located and centered along the opposite rear 16’ wall.
I optimize the bass at my listening seat by playing music containing good and repetitive bass, placing sub#1 at my seat and walking around the perimeter of my room in a counter-clockwise direction beginning at the front right corner of my room. I walk slowly along the front 16’ wall until I find the exact spot that the bass sounds best to me. Once determined, I relocate sub#1 to that exact position.
I then place sub#2 at my seat and continue walking slowly from sub#1 until the bass sounds best to me. Once determined, I relocate sub#2 to that exact position. This process is sequentially followed until all 4 subs are optimally positioned.
Last, I sit in my listening seat, replay the music with good bass and verify that the bass sounds very good. It’s important to mention that while the bass sounds exceptionally good at this point, I could not determine where the bass was coming from even though there was a sub on each 23’ wall with my listening seat in the middle of the rear 16’ wall between them and 2 subs located along the front 16’ wall.
Next, I optimally position my main L+R Magnepan 2.7QR panels along the front 16’ wall, about 8’ apart and each about 4’ away from this wall into the room, in relation to my listening seat and playing full range but rated bass down to only 37Hz.
Replaying the same music now heard in full range, everything becomes coherent and well integrated. There is a wide and dep soundstage illusion.
My main point being, with the benefit of now hearing the bass harmonics above about 80Hz, I could now determine where the instruments producing the deep bass notes below about 80Hz were coming from within this soundstage illusion. I believe hearing the deep bass harmonics above 80 Hz enables this no matter how many subs are used in a system.

Sorry this was so long but I find this a difficult concept to explain without a lot of detail. I hope I was successful.

Tim

Swarm or maybe buy a few parts express subs and do sim to swarm. Or just build a proper sub bass horn and be done for life.

If you care to learn a bit  Dr Geddes PDF paper on multiple subwoofers  https://drive.google.com/file/d/0BxgUOGOB5HbfR0JTRF9XZjkyUms/view