Subwoofer Question

While I am a huge advocate of acoustics treatment, the op mentions they have a small listening space  (Hey op, what are the measurements). Good, emphasis on good, bass control with acoustic treatments means large acoustic objects. That may not be feasible in the space. With the exception of resonators, which can still be large to be effective, or too narrow band, any absorber is going to be big.  With two subs, the nodes will be much less pronounced and easier to control with acoustics.

erik_squires8,841 posts04-17-2020 1:59pmSpend all the money you were going to spend on a 2nd sub and treat your room first. Talk to GIK. Then see if you still feel a 2nd sub is needed.

This question is probably just hypothetical since I doubt my wife would approve. even though she is very understanding about big speakers. I use Bill Fitzmaurice designed HT Tuba folded corner horn subs (18 cubic feet each) and love them.  If I added two more of these subs to my system all four subs would obviously have to be in the room's four corners.  I understand that asymmetrical placement is a part of the swarm sub idea, but would four horns in the four corners achieve enough improvement to be worthwhile?

If you are using 4 corners, then a specific version of a bass array, also called DBA, but in this case double bass array, may be something to look at based on your physical implementation.


https://en.wikipedia.org/wiki/Double_bass_array

Kingharold asked, "would four horns in the four corners achieve enough improvement to be worthwhile?"

Todd Welti of Harmon International investigated symmetrical subwoofer placements using simulations, and four subs with one in each corner was one configuration he examined in this paper:

https://www.harman.com/documents/multsubs_0.pdf

Corner placement optimizes for low-end extension, but not for smoothness.

From the paper: "One subwoofer in each corner has good low frequency support, but does not perform quite as well as one subwoofer at each wall midpoint..."

So imo four subs, one in each corner, is likely to be an improvement over two subs in two corners. Whether or not the improvement will be "worthwhile" is a judgment call, but I’ll go out on a limb and say "probably". The reason I think so is, the ear has a heightened sensitivity to frequency response issues in the bass region. This is implied by equal-loudness curves, which bunch up south of 100 Hz, such that a 5 dB difference at 40 Hz is subjectively comparable to a 10 dB difference at 1 kHz. In English, a little bit of improvement goes a long ways in the bass region, in my opinion.

Also, the Fitzmaurice Tubas are big enough that you could probably orient the mouth of each one differently with respect to its corner and get a little bit of asymmetry that way. And if such orientation is not an improvement, easy to undo.

Heaudio wrote: " a specific version of a bass array, also called DBA, but in this case double bass array, may be something to look at..."

My understanding is that a double bass array normally consists of four subwoofers on the front wall, each 1/4 of the way in from its nearest corner (this configuration theoretically producing a planar wave). Then a second identical array is placed on the rear wall. The polarity of the signal going to the rear array is inverted and it is delayed by the amount of time it takes for the sound from the front array to reach the rear wall, the intention being to cancel the front wave when it reaches the rear wall.

(Personally I try to use the term "distributed multi-sub system" rather than "distributed bass array" because the latter invites the abbreviation "DBA", which as you pointed out also stands for "double bass array". Not that I object to anyone else using "distributed bass array" abbreviated as "DBA", as the meaning is usually clear from the context.)

Duke

I will express a somewhat different experience based on my experience.  I had Martin-Logan CLSs paired with a pair of Entec LF-20 subs.  These subs each had two 10 inch woofers that were servo controlled and I had new surrounds put on by the original manufacturer. Each was probably about 75 lbs and the pair would have been about $6,000 in the late 80's to early 90's.  A very high-quality pair of subwoofers.

When I moved up to a pair of Martin-Logan CLXs, I wanted to take advantage of the custom crossovers provided by Martin-Logan for these speakers as mains, so I sold the Entecs and bought one Martin-Logan Balanced Force 210 sub.  It sounded great with the custom crossover filter.  It also had more than enough output for my 25x20x11 listening room. It is currently placed in between the mains.

What is the game changer for this subwoofer though it the ability to use the Perfect Bass Kit (PBK) to create an inverse correction filter for room nodes.  To be honest, I was skeptical at first, and put off doing the set-up for weeks, to my deficit.  The difference in bass quality and musical enjoyment between corrected and uncorrected is stunning.  You know how in some songs some of the bass notes are more prominent than others?  That ends.  Runs up and down the neck of an electric bass are now essentially equal in volume.  Same with double bass and lower cello, etc.  I agree with many above that multiple subs provide a smoother response across the whole room, which is a great reason for multiple, but in my single listening position, I can get a much flatter bass response curve than most uncorrected multiple sub systems.

@puppyt, if you have not done the PBK, it is essential before trying other things.  If you are still dissatisfied, I am a potential buyer of your 210.  I want another one, not for output, but I do think there is stereo bass information to be recovered in some recordings, principally in live concert recordings.