Are big subwoofers viable for 2 channel music?


In thinking about subwoofers to get for a large future listening space (30' x 30'). So far there seems to be a lot of great options for smaller subs for music.. such as the rel s812. Now my main focus will be music but I do plan to do some home theater on the system and I do enjoy subs that reach low and have strong but clear sub-bass. Would a large sealed sub still be able to provide clean tight bass that digs low and thus satisfy both duties. Can it ever match the speed and precision of a pair or more of rel 812s? Something like PSA S7201 or Captivator RS2?

A realize a smaller sub has a smaller moving mass and thus for a given level of power would be faster than a bigger sub with a bigger moving mass (driver mass). But a large sub would have to move less to achieve the same SPL and would reach lower.

Anyhow what do you guys think? Thanks.
smodtactical
Hello smodtactical,

      I agree with bdp24,   that four Rhythmik F12 subs would perform well in a DBA configuration and that four F18 subs would likely perform just as well but with a bit more deep bass power and impact.
     I think it's important for you to understand a few facts about how humans perceive bass:

1.  We can generally not locate bass tones (determine exactly where the sound is coming from) below about 80 Hz and the deepest bass tone we can generally hear is 20 Hz,  Our bodies can feel deeper bass tones below 20 Hz but we generally can't hear them.  Also, there are very few musical instruments that are even capable of producing bass tones below 20 Hz, pipe organs are the only ones I'm aware of.

2.  Because of this, we perceive all bass under about 80 Hz as mono and not stereo.  Recording engineers have known this for decades and have been summing all bass below about 100 Hz, as well as filtering out bass frequencies below about 20 Hz, since the 1950s.  This is also why you can safely disregard any suggestions of positioning subs in your room like main speakers, with a carefully positioned left and right speaker.
     In other words, there's no such thing as stereo deep bass.  Best in-room bass results will be achieved by operating your subs in mono mode and positioning each sequentially for optimum bass performance.  I can explain exactly how to do this, regardless how many subs you ultimately choose to utilize in your room, in a future post.

3.  Virtually all commercially available musical content produced in the last 80 years, has the bass below about 100 Hz summed to mono and bass below 20 Hz filtered out.  So, even if you did place your subs in a left and right stereo physical configuration, there's a complete lack of content with stereo deep bass to play on them. 
     My main point, again, is to disregard any suggestions or notions of positioning or operating your subs for stereo playback.  Just operate them in mono mode and position each for best bass performance.
    Beyond the above, it mainly comes down to cost and convenience.  The Audio Kinesis Swarm 4-sub DBA system costs $3K and will produce high quality bass in your room down to the audible limit of 20 Hz. I've never auditioned any Rhythmik subs but believe they are high quality subs at reasonable prices.  I also think it's likely that utilizing four F12 or F18 subs in a DBA configuration in your room would outperform the Swarm complete system.  
     Of course, the decision is completely up to you.  I just want to make sure your realize that either Rhythmik option option will cost significantly more and will be less convenient to setup since you'll need to set the volume, frequency cutoff and phase controls separately on each sub, rather than once for all four subs on the Swarm.  
     However, I also believe that utilizing two F12 and two F18 subs would perform very nearly as well as four F18s in your room, helping with the cost but not the convenience.

Later,
 Tim
I just want to make sure your realize that either Rhythmik option option will cost significantly more and will be less convenient to setup since you'll need to set the volume, frequency cutoff and phase controls separately on each sub, rather than once for all four subs on the Swarm.
Not owning a Swarm system I may be missing something, but I would think that having the ability to fine tune each individual sub would give one more flexibility and customization in their setup.  When I set up my four subs I took SPL readings for each sub to adjust the output so that they would be equal from my listening position.  I have one sitting just a few feet from my listening position and another on the far side of the room.  It doesn't seem that having them all at the same level would be a good thing.


Four independent subs allows for maximum adjustability and flexibility. The controls on the Rythmik plate amps are the most extensive of any line I’m aware. They include:

- Continuously-variable Phase Control knob providing 0 degrees to 180 degrees of rotation (0 ms to 16 ms delay).

- On the non-XLR models, both high level (speaker binding posts) and line level (RCA jacks) hookup.

- Continuously-variable x/o filters from 25Hz to 120Hz, 12dB/octave and 24dB/octave, presets at 50Hz and 80Hz.

- High/Medium/Low Damping switch.

- 1-band PEQ with Bandwidth and Gain control.

- 14Hz/20Hz/28Hz Extension Filter switch.

- Rumble Filter switch..

- On most models both Line In and LFE In inputs.

- Two XLR models, great for sub locations requiring a long interconnect. And the XLR2 model provides Master/Slave operation for any number of subs, should you not want to adjust them separately.

And don’t forget, the patented Rythmik Direct Servo-Feedback circuitry. Plus, woofers designed by Brian Ding and manufactured by TC Sounds (you hardcore subwoofer guys know THAT name ;-) .

Rythmik. At least look into them.

I have a medium/ large area and use 2 HP Rythmik 15" subs.  They do anything you ask them to do. High damping acts like a speaker. Start and stop on a dime. I believe it's the servo design. You wouldn't know I have subs until they're called upon. I use them for music and movies. Actually, you still dont know the subs are there, but I dont have speakers that go that low. They are absolutely seamless. 

I did have my audio set up by a pro. Took 5-6 hours for HT setup, but it can definitely be seemless.

I suggest 2 f18s for your room, then if needed, you can always get 2 more. I doubt you'll need more. You do get a 2 sub discount. 

Good luck
 
big_greg and bdp24,

I agree with you both that four independent subs allows for maximum adjustability and flexibility. I know from personal experience, however, that this level of adjustability and flexibility is not required for excellent bass performance results using the Swarm system.
Audio Kinesis does state that bass performance can possibly be improved by inverting the phase on one of the four subs in some rooms but I noticed no improvement in my room with any of the subs having their phase reversed. Also, their suggested method of phase inversion is simply to reverse the pos. and neg. wires at the sub terminal connections.

big_greg: "I have one sitting just a few feet from my listening position and another on the far side of the room. It doesn’t seem that having them all at the same level would be a good thing."

My listening seat is positioned along my rear wall between two of the four subs, one positioned about 8’ away along the left side wall and the other about 3’ away along the right side wall. The two other subs are both about 20’ away along the front wall. All are operated in mono mode and at identical volumes. I perceive the bass on both music and HT as coming from the front of the room and never perceive the bass as coming from the subs nearest me to the right and left of my listening chair.
I believe this is due to the efficacy of the scientifically proven DBA concept that works exceptionally well in virtually any room and with any pair of main speakers.
This DBA concept takes advantage of both how bass sound waves behave in domestic sized rooms and the accumulated psycho-acoustic knowledge concerning how humans perceive sound at various frequencies. I can state with certainty that the 4-sub DBA concept works exceptionally well in my room and I believe it will work equally well in virtually any other room.

Tim