Has anybody heard the new KEF KF92 sub? What are your opinions?

[JimA84]

I heard from Brian Ding, designer of the rumble filter for the Rythmik G22-SE.

His main design concern was thermal stress and overexcursion from HT tracks with extreme output at 10 Hz, a very legitimate concern.

He said that the roll off for the G22 rumble filter is less sharp than their FV18 so it only cuts 2.5 dB at 16 Hz.

I wanted to clarify this for anyone considering the Rythmik G22-SE.

Thanks to Brian for his detailed response.

 

[bodhi]

I had two KF92s and replaced one with SVS SB-4000 just for fun. I'd say that most of the time there is absolutely no difference in a medium sized room. The remaining KEF is placed in corner though and that boosts lowest frequencies a LOT. The SVS is located in pretty bad spot but it can power through nicely.

Anyways, when comparing the two, I agree with the rest. The KEF just lacks the raw, shaking power down low. It doesn't really matter to me though, but there it is. And the price is ridiculous, so definitely wouldn't recommend.

 

[JimA84]

We went through this with computer cpus decades ago. Lofty performance claims that often fell short. Benchmark tests where manufacturers designed to the test instead of real world scenarios.

I think it's time for an industrywide commitment to a new set of metrics that are scientifically valid, fair and reflect real world scenarios. Nobody lives in an anechoic room unless you huddle in the woods, in which case you likely aren't reading this. Unless you live in a war zone, not entirely unlikely at present.

The performance specs we rely on are so loose and misleading and are regularly subverted by Harvard MBAs intent on marketing.

Instead of debating about where to place the subwoofer or whatever we need to publish measurements in real in room scenarios that reflect what people can reasonably expect.

Including the level of outcome variability of placement largely as a negative judgment.

We need to develop a measurement model that accomodates a variety of common scenarios as well as a few outliers, standardize it, and demand industry conformance.

And to accommodate the cheap 2×4 cladded firetrap construction of modern homes which offers minimal sound insulation.

And design it deliberately to obfuscate MBAs who try to beat the testing with an inferior design by "teaching to the test" with AI software.

We need to kill the Bose 901 while rewarding creative performance that delivers good sound in an ordinary realistic home that doesn't require a forklift to install.

We did this decades ago in computing, though things have largely fallen off the rails more recently so perhaps a revisit is due.

This will require a dedicated effort of scientists, engineers and psychologists to develop new requirements specifications for human listening spaces and equipment to deliver an audiophile experience at reasonable cost

Including things like home construction standards to reduce the impact of subwoofers on neighbors.

And promotion of legislation to forbid unreasonable complaints. In other words, sound that is "audible" outside the home is absurd when trucks are blasting jake brakes on the freeway a block away.

Instead of arguing about which piece of equipment is "best" we should be looking outward.

Otherwise we will have the same experience with the intolerant new neighbor who calls the police because he can faintly hear music with his windows open and it drives him nuts, regardless of his own household noise.

Meaning all your efforts are for naught as you watch the police hauling off your equipment under the view of the grinning neighbor.

The one who will be evicted in six months for nonpayment, leaving pet soiled carpets. But who exploited your stereo to obtain a lein on your property so he can sell it out from under you, his whole intention from the beginning.

Unfortunately this is all too common.

In my experience there are a huge number of people who not only hate audiophiles but are willing to exploit community intolerance or indifference to engage in MBA wealth extraction.

The same thing is going on where I live to exploit or destroy businesses that offer live music entertainment.

If you simply argue among yourselves and don't promote societal acceptance then pretty soon we will only be able to listen through closed back headphones.

(I hate headphones)

 

[JimA84]

Another choice is the idea of "ground shaking" as opposed to accurate bass extension.

If you want "ground shaking" you might want to put a vibrator under your seat.

I only care about the sound.

I indeed would love to not annoy the neighbors.

Dual opposed subwoofers are often criticized by those who mistake bass for an earthquake.

Bass is experienced through your ears. Vibration is experienced through your ass.

Thinking is often similarly located.

 

[Vacceo]

I wonder how much could KEF gain in SPL with a dual 10 or 12 inch woofer. It´d still be a relatively compact subwoofer, but the output may increase quite a bit.

 

[JimA84]

I wonder how much could KEF gain in SPL with a dual 10 or 12 inch woofer. It´d still be a relatively compact subwoofer, but the output may increase quite a bit.

Actually I have come to rethink this a bit

First off, the design of the KEF driver appears to be closer to 7 inches in T/S standards.

I do like their elegant heat sink design and the notion of using two separate 500 W amps instead of one 1,000 W. I don't like their lack of XLR input.

I still love the product.

I am seriously starting to look at the ELAC DS1000 though.

This is heavier at about 71 pounds but still manageable for a single person to move.

They advertise output of 115 dB and in room response to 15 Hz -3dB.

It also has XLR input as well as a 12 V trigger to turn it off when not in use.

Their suspension is amusing because it looks like rumpled clothes, but they claim this gives them longer suspension.

I also like the Rythmik G22-SE now that I have spoken with the design engineer about the rumble filter but it's a little heavy at about 102 pounds.

The B&W line seem promising but they are very costly. I'm also not convinced that it's a good idea to locate the heat sink on the bottom.

A powerful amp needs good ventilation.

Putting the heat sink on the bottom may add to esthetics but it compromises airflow.

They do have the pretty rosewood cabinet option.

I would say that two of any of these products would produce good results in a moderately sized room. Perhaps the KEF in a bit smaller space. But any of them would deliver. You really want two subs to balance the room response. Even the Monoprice SSW-12 is a good choice on a limited budget. You can pump your receiver or processor EQ to +6 dB at 25 Hz and I think you'll be happy. Your neighbors may not agree

If you simply want the HT experience of shaking the house to the rafters and don't care that the neighbors are going to SWAT your home, You should go with something like 16 or 18 inch ported subs with 2000 W amps.

I'm more interested in high fidelity music than movie soundtracks, so YMVV.

But I did once have a stereo in a small apartment living room with a pair of Samson Rubicon 5a ribbon active monitors and no subwoofer and it still produced a pretty good home theater experience in addition to the music quality.

No real response below 59 Hz, but at least it didn't annoy the neighbors too much.

 

[CurtR]

Actually I have come to rethink this a bit

First off, the design of the KEF driver appears to be closer to 7 inches in T/S standards.

I do like their elegant heat sink design and the notion of using two separate 500 W amps instead of one 1,000 W. I don't like their lack of XLR input.

I still love the product.

I am seriously starting to look at the ELAC DS1000 though.

This is heavier at about 71 pounds but still manageable for a single person to move.

They advertise output of 115 dB and in room response to 15 Hz -3dB.

It also has XLR input as well as a 12 V trigger to turn it off when not in use.

Their suspension is amusing because it looks like rumpled clothes, but they claim this gives them longer suspension.

I'm more interested in high fidelity music than movie soundtracks, so YMV

I have the ELAC ds1000 currently, and have had it for over a month but got an extension on the return policy... I'm having trouble integrating into my system, which is kind of surprising with the 8-band parametric up to 200hz that's included. I am not currently satisfied with it, and it's even more $ than the KEF. So far, the best descriptor of the sound profile of the ELAC is "soft"... I want tight, accurate, and percussive; it's possible I may need a ported??? Interestingly, I found a review of the elac ds1200, and the reviewer mentioned a "soft bottom octave," so apparently I'm not alone in my perceptions! It was "ah-hah, so it's not just me..."

I'm also not sure that the ELAC ds is technically force-cancelling design, because the woofers are not diametrically opposed... they are at angles.

So, I just received a new RSL Speedwoofer 10s mk2, and I'm going to A/B it with the ELAC. $500 shipped and delivered for the RSL; not as pretty of cabinet, but not bad either in white. I'm suspecting the RSL may beat the ELAC, and at 1/4 or 1/5 the price, for my purposes. The RSL isn't "dressed up," but the cabinet is solid and about the same size as the ELAC, it has a port, and one front firing 10" instead of the dual sided ds1000... my theory is that RSL has put the money into the performance guts. But, I haven't even hooked up the RSL yet, so I can't report any findings yet. I'm new to it, but I also got a Umik-1 mic and the REW app, so I'll do some "objective" measurements in my room too, for both subs.

I went for the ELAC based on the cool design, features, and supposed specs... and I did get a discount on it, but still it was $1850 shipped and delivered. Two ELACs would run me $3700 (which I'd actually be willing to do IF demonstrably superior), whereas two RSL 10s mk2 would be $1000 total, or $1100 if get a custom grey grill for it... a $2500 savings to go dual. I will check back in once I've put them through my comparisons and tests over the course of the next week.

 

[JimA84]

I have the ELAC ds1000 currently, and have had it for over a month but got an extension on the return policy... I'm having trouble integrating into my system, which is kind of surprising with the 8-band parametric up to 200hz that's included. I am not currently satisfied with it, and it's even more $ than the KEF. So far, the best descriptor of the sound profile of the ELAC is "soft"... I want tight, accurate, and percussive; it's possible I may need a ported??? Interestingly, I found a review of the elac ds1200, and the reviewer mentioned a "soft bottom octave," so apparently I'm not alone in my perceptions! It was "ah-hah, so it's not just me..."

I'm also not sure that the ELAC ds is technically force-cancelling design, because the woofers are not diametrically opposed... they are at angles.

So, I just received a new RSL Speedwoofer 10s mk2, and I'm going to A/B it with the ELAC. $500 shipped and delivered for the RSL; not as pretty of cabinet, but not bad either in white. I'm suspecting the RSL may beat the ELAC, and at 1/4 or 1/5 the price, for my purposes. The RSL isn't "dressed up," but the cabinet is solid and about the same size as the ELAC, it has a port, and one front firing 10" instead of the dual sided ds1000... my theory is that RSL has put the money into the performance guts. But, I haven't even hooked up the RSL yet, so I can't report any findings yet. I'm new to it, but I also got a Umik-1 mic and the REW app, so I'll do some "objective" measurements in my room too, for both subs.

I went for the ELAC based on the cool design, features, and supposed specs... and I did get a discount on it, but still it was $1850 shipped and delivered. Two ELACs would run me $3700 (which I'd actually be willing to do IF demonstrably superior), whereas two RSL 10s mk2 would be $1000 total, or $1100 if get a custom grey grill for it... a $2500 savings to go dual. I will check back in once I've put them through my comparisons and tests over the course of the next week.

In looking more closely at the ELAC I found some test graphs which lead me to believe that the ELAC drivers have a fairly high Fs which causes the response to roll off very sharply below 22 Hz or so. I mean like 10 dB or more.

This is unfortunate because it's pretty hard to EQ your way out of that situation.

Perhaps their "rumpled" suspension is too stiff for some reason.

I hope they will revisit this because otherwise it appears to be an excellent product.

On the surface it looks like a suspension compliance issue.

Perhaps with more compliant suspension materials it could deliver the anticipated extension.

 

[CurtR]

In looking more closely at the ELAC I found some test graphs which lead me to believe that the ELAC drivers have a fairly high Fs which causes the response to roll off very sharply below 22 Hz or so. I mean like 10 dB or more.

This is unfortunate because it's pretty hard to EQ your way out of that situation.

Perhaps their "rumpled" suspension is too stiff for some reason.

I hope they will revisit this because otherwise it appears to be an excellent product.

On the surface it looks like a suspension compliance issue.

Perhaps with more compliant suspension materials it could deliver the anticipated extension.

interesting... and where did you find those test graphs for the ELAC?

And, note that if it rolls off fast at 22, well so does the RSL 10s mk2, which from what I've seen measures pretty flat down to 22 and still extends (rolled off) a bit below too, similarly to what you describe for the elac. So why the extra $2000 asking price EACH, for the ds1000? seriously, the elac asking price is FIVE TIMES the RSL Speedwoofer. (still almost 4x $$ even with the big discount I got). The "nicer" box and the parametric eq? I have yet to see anyone with an RSL rue not having a p eq. ... everybody comments on how easy they are to integrate.

 

[JimA84]

interesting... and where did you find those test graphs for the ELAC?

And, note that if it rolls off fast at 22, well so does the RSL 10s mk2, which from what I've seen measures pretty flat down to 22 and still extends (rolled off) a bit below too, similarly to what you describe for the elac. So why the extra $2000 asking price EACH, for the ds1000? seriously, the elac asking price is FIVE TIMES the RSL Speedwoofer. (still almost 4x $$ even with the big discount I got). The "nicer" box and the parametric eq? I have yet to see anyone with an RSL rue not having a p eq. ... everybody comments on how easy they are to integrate.

I sort of went on a binge of investigating subwoofers a month or so ago and didn't bother to save or document everything.

This is one article on the ELAC DS1200.

ELAC DS1200 12" Dual-Opposed Subwoofer Review

Performance Features Build Quality Value

www.soundandvision.com

Not a great example but most of what I have seen indicates a very sharp rolloff around 20 Hz or a bit higher.

RSLs are not generally known for extremely low bass extension, rather quality for the cost.

The hype surrounding the ELAC, however, makes the lack of low frequency extension somewhat disappointing.

 

[CurtR]

I sort of went on a binge of investigating subwoofers a month or so ago and didn't bother to save or document everything.

This is one article on the ELAC DS1200.

ELAC DS1200 12" Dual-Opposed Subwoofer Review

Performance Features Build Quality Value

www.soundandvision.com

Not a great example but most of what I have seen indicates a very sharp rolloff around 20 Hz or a bit higher.

RSLs are not generally known for extremely low bass extension, rather quality for the cost.

The hype surrounding the ELAC, however, makes the lack of low frequency extension somewhat disappointing.

I'm glad I found somebody else investigating the ELAC ds-series... I've been interested ever since I saw 'em. I wish I was satisfied, because that was my intent when I pulled the trigger on one: pony up for the luxury sub and be done, maybe add a second one down the line sometime if I want to. Maybe I can still salvage my satisfaction and be happy with it and be done, so I'm going to give it another week of tweak and measure, measure and tweak... and compare to a well-respected inexpensive alternative in the RSL. Then I can have a more mature and confident determination.

right, yeah that's the ds1200 review I came across... and where I found this buried at the end:

"The ELAC DS1200 did soften the lowest octave when I pushed the pace, but frankly that’s not the least bit surprising given the aforementioned pesky bit of physics."

and I think that's what I'm hearing ... the "softening" of the lowest octave. And, if that really is true, then it's really not sound character that I want. But for many people, such a softening might actually be attractive, more gentle or subtle, and more acceptable to spouse and neighbors and whatnot.

But the ds1000 is a beautiful piece of work, to be sure. Attractive to look at, and it does sound good. I'm going to work with it some more, do the REW and see if I can see some sort of overlap with my mains that may be causing some mud but that can be fixed perhaps with settings, and do my RSL comparison.

What intrigues me though is the flatness of the RSL 10s down to 22 and really even at 20, and still some rolloffed sub-20. What I've read about it is "it may not have the ultimate extension, but what it does do it does very well indeed." And if that rear port adds that percussive "kick" that I'm looking for, well then that might seal the deal for me. (not that I'm a "boom" type of guy... I want accurate and integrated... but I do know live music and live music has a kick.) Now the RSL 12s DOES have the extension, flat to about 16, but it's too large for my (current) space...

Now, this is a KEF kf92 forum, but now KEF updated it to the kc92 ... and the kc92 lists almost $500 less than the Elac. So, at list, dual kc92 is $4000, and dual Elac ds1000 is $5000. ... It'd be really interesting to do an A/B with the new version of the KEF vs the ELAC... vs the RSL 10s ($1000 for two) or the larger RSL 12s ($1800 for two) . I'm tempted to quick order a kc92 from Crutchfield or something, while I still have this ELAC and the RSL, and actually find out for myself.

I'm a long-time frugal audiophile, inspired by my early experience with my modest Philips 20wpc receiver coupled with Epi 100 speakers, which almost always sounded better than the "monster" receivers and amps and larger speakers that some of my friends and acquaintances have had, up to and including the vaunted Yamaha ns1000 speakers... Somehow that trusty Philips got swallowed up along the line in moves and in time, but I still have those Epi speakers (updated with new capacitor/crossover) and they STILL sound better than most anything else I hear out there in the real world, and I paid $140 for the pair back in 1979. Epi inverted dome tweeter is one of the best ever, still. Therefore, I know that less expensive but properly designed simple gear can definitely sound as good or better than more expensive fancy stuff, and so I'm particularly intrigued by what RSL might bring to the subwoofer table.

That said, the jury is still out on all this subwoofer business, but I will certainly update you with my conclusions.

 

[JimA84]

I agree with your "frugal audiophile" sentiment. That's my main drive to investigate these issues in detail.

The ELAC DS1000 is indeed beautiful and very well made. But both it and the bigger model are for people satisfied with ~20 Hz bass extension. If that's acceptable, the ELAC is a beautiful and relatively affordable option.

It also offers the tradeoff of very high output. Andrew Jones definitely knows his craft.

The KEF trades off some output for truly heroic bass extension. Both the KEF and the ELAC are compact, attractive furniture designed to blend into room decor, not stand out like Wilson Audio's Thor's Hammer or some JL models. Monoprice (Monolith) also makes very good subwoofers if you're looking for high output, low extension and you don't mind relatively big and very heavy units. Monoprice and JL both publish very detailed measurements for their premium products.

To me,the main difference between the ELAC DS1000 and the KEF KC92 is the tradeoff between peak output and deep bass extension.

Both are beautiful products and will fit well with room decor.

I personally would advise getting two smaller subs and locating them where they excite different room modes over one larger sub. If you do choose one sub it's often best to just put it in the corner to maximize the room gain.

Using two permits smoother bass response over a larger listening area.

Indeed, if you are willing to accept bigger and heavier units (over 200 pounds in some cases) Monoprice has some of the best values in THX Certified Ultra subwoofers.

The new Dirac bass correction with multiple subwoofers independently adjusted is also a good thing to check out.

 

[waynel]

I sort of went on a binge of investigating subwoofers a month or so ago and didn't bother to save or document everything.

This is one article on the ELAC DS1200.

ELAC DS1200 12" Dual-Opposed Subwoofer Review

Performance Features Build Quality Value

www.soundandvision.com

Not a great example but most of what I have seen indicates a very sharp rolloff around 20 Hz or a bit higher.

RSLs are not generally known for extremely low bass extension, rather quality for the cost.

The hype surrounding the ELAC, however, makes the lack of low frequency extension somewhat disappointing.

Investigating subwoofers? Sweetchaos has you covered:

Subwoofer Comparison

I've created a *slightly large* subwoofer comparison spreadsheet. :D Info: -==Link to my Subwoofer Comparison spreadsheet ==- https://bit.ly/SubwooferComparison

www.audiosciencereview.com

 

[JimA84]

I tried to access this but I got some Google login page despite that I was logged into my Google account.

 

[CurtR]

Investigating subwoofers? Sweetchaos has you covered:

Subwoofer Comparison

I've created a *slightly large* subwoofer comparison spreadsheet. :D Info: -==Link to my Subwoofer Comparison spreadsheet ==- https://bit.ly/SubwooferComparison

www.audiosciencereview.com

and those measures show the excellent performance of the RSL, both the 10s and the 12s.

and unfortunately, there are no measures of the ELAC ds1000 nor ds1200.

but, like I said, I'm going to measure them in my own room here with my new REW setup and see what's going on.

from an external aesthetic pov, of course the ELAC or the KEF wins ... and that is certainly something to take into consideration: it is an object that you have to like living with overall; ultimate sound is one thing, but not the only thing, when it is something you're looking at in your space. "lifestyle" factor, including visual appeal, that some people are so dismissive of (note some of the derision directed at "lifestyle subs"), is important to us that do have lifestyles and aesthetic preferences in our living spaces. that said, although not as lux as the ELAC and the KEF, the RSL in white with the grey grill is not shabby or ugly either and might even blend better with casual-chic decor

 

[waynel]

I tried to access this but I got some Google login page despite that I was logged into my Google account.

try this direct link:

Subwoofer Comparison (by @sweetchaos)

CEA-2010-A Manufacturer (sorted by, first),Model (sorted by, second), Discontinued ,Mfg Link,Manual, Announced Date ,Price,Currency,Frequent Sale Price,Converted to USD,Converted to CAD,Converted to GBP,Converted to EUR,# of Woofers,Woofer Size (in),Type,Passive,CTA-2010-B data available. If 'Ye...

docs.google.com

If that doesn't work perhaps try a different browser

 

[JimA84]

Thanks for your efforts. They can only benefit the community.

Actually some of the RSL products are rather cute with the metal feet with the RSL imprint.

 

[CurtR]

Thanks for your efforts. They can only benefit the community.

Actually some of the RSL products are rather cute with the metal feet with the RSL imprint.

you're thinking of REL ... the RSL have rubber feet that aren't visible.

 

[JimA84]

Sorry... You're right there.

RSL is really not in the same league

Possibly because I never really considered REL in my search Let alone RSL.

The mother and child reunion is only a keystroke away.

The funny thing is that you might consider Monoprice yet another low rent pretend company until you look. They are literally what JL were early in their career.

And we can see where that went. No sane person would quesion JL as one of the best premier producers of the very best subwoofers made at any cost.

Unfortunately the price grew with the reputation so owning a JL now is a sign of success. But you can't go wrong there.

A Monoprice Monolith is kind of like the JL I bought a couple decades ago when nobody had heard of them.

Ungodly quality at a remarkable price.
The quality is still ungodly, only with success the price goes up.

Yet I digress.

I am looking for a horizontally opposed subwoofer with modest physical volume good output volume and low bass extension. One that I can move or carry up the stairs without calling the chiropractor.

I also considered the Rythmik G22. If they made it with the sharp low corner rumble filter from the F18 as an option I might consider it but as is it cuts off too high for my tastes. It's also bigger and heavier than I want, but the price is attractive and it's a quality product.

Were I to use this I would leave the rumble filter off and use a Behringer active crossover to apply a 8 pole 48 dB/octave Butterworth high pass filter at 14 Hz.

I still think they could probably offer the lower corner, steeper rumble filter as an option, but without that I would definitely go the active filter route.

All things considered I have pretty much settled on two KEF KC92 subwoofers with Dirac correction with the $500 option for independent subwoofer correction.

The XLR processor I like can support this, and if the output proves inadequate to match the mains (unlikely since the KEF can hit 110dB), the processor can handle up to five independently Dirac corrected subs.

I think five KEF KC92s should be sufficient to melt your brain.

Since the KEF KC92 doesn't support XLR I would use Jensen passive transformers near the subs with about a 2 foot RCA unbalanced RG6 cable to complete the connection.

If locating a sub in the opposite diagonal corner KEF offer a very affordable high quality Bluetooth wireless interface that is integrated with the design.

My own preference for compact, reasonable weight horizontally opposed subwoofers with extension below 16 Hz leads me to two KEF KC92s.

If ELAC made the DS1000 with lower extension I might choose that, but for now the KEF KC92 wins.

Though if I went with single driver subs and weight wasn't an issue I would without question go with two Monoprice Monolith THX Ultra 16 inch subs.

These are big and 172 pounds each, but they blow away everything including Wilson Audio's Thor's Hammer at less cost on sale now than the KEF KC92.

 

[waynel]

Sorry... You're right there.

RSL is really not in the same league

Possibly because I never really considered REL in my search Let alone RSL.

The mother and child reunion is only a keystroke away.

The funny thing is that you might consider Monoprice yet another low rent pretend company until you look. They are literally what JL were early in their career.

And we can see where that went. No sane person would quesion JL as one of the best premier producers of the very best subwoofers made at any cost.

Unfortunately the price grew with the reputation so owning a JL now is a sign of success. But you can't go wrong there.

A Monoprice Monolith is kind of like the JL I bought a couple decades ago when nobody had heard of them.

Ungodly quality at a remarkable price.
The quality is still ungodly, only with success the price goes up.

Yet I digress.

I am looking for a horizontally opposed subwoofer with modest physical volume good output volume and low bass extension. One that I can move or carry up the stairs without calling the chiropractor.

I also considered the Rythmik G22. If they made it with the sharp low corner rumble filter from the F18 as an option I might consider it but as is it cuts off too high for my tastes. It's also bigger and heavier than I want, but the price is attractive and it's a quality product.

Were I to use this I would leave the rumble filter off and use a Behringer active crossover to apply a 8 pole 48 dB/octave Butterworth high pass filter at 14 Hz.

I still think they could probably offer the lower corner, steeper rumble filter as an option, but without that I would definitely go the active filter route.

All things considered I have pretty much settled on two KEF KC92 subwoofers with Dirac correction with the $500 option for independent subwoofer correction.

The XLR processor I like can support this, and if the output proves inadequate to match the mains (unlikely since the KEF can hit 110dB), the processor can handle up to five independently Dirac corrected subs.

I think five KEF KC92s should be sufficient to melt your brain.

Since the KEF KC92 doesn't support XLR I would use Jensen passive transformers near the subs with about a 2 foot RCA unbalanced RG6 cable to complete the connection.

If locating a sub in the opposite diagonal corner KEF offer a very affordable high quality Bluetooth wireless interface that is integrated with the design.

My own preference for compact, reasonable weight horizontally opposed subwoofers with extension below 16 Hz leads me to two KEF KC92s.

If ELAC made the DS1000 with lower extension I might choose that, but for now the KEF KC92 wins.

Though if I went with single driver subs and weight wasn't an issue I would without question go with two Monoprice Monolith THX Ultra 16 inch subs.

These are big and 172 pounds each, but they blow away everything including Wilson Audio's Thor's Hammer at less cost on sale now than the KEF KC92.

since you couldn't access the spreadsheet I've extracted a relevant comparison here

Manufacturer	Model (sorted by, second)	Converted to USD	# of Woofers	Woofer Size (in)	Type	Source of CEA-2010-A data. Shown as 2m Peak SPL.	Version Tested	15 hz	20 hz	25 hz	31.5 hz	40 hz	50 hz	63 hz	80 hz	Weight (lb)	H (in)	W (in)	D (in)	Volume (ft^3)	Footprint (W*D) (ft^2)
Rythmik	F12	1120	1	12	sealed	Brent Butterworth		95	97.6	100.7	107.5	112.3	113.1	114.4	113.6	75	15.8	15.8	17	2.4	1.9
KEF	KF92	2000	2	9	sealed	ErinsAudioCorner			86	91.6	95.4	101.1	103	104.4	106.3	44.1	13.9	13	14.2	1.5	1.3
	Difference	880​						N/A	11.6​	9.1​	12.1​	11.2​	10.1​	10​	7.3​	30.9​

As you can see from the data, the Rythmik F12 outperforms the KF92 by 11.6dB at 20Hz, and at 15Hz the KF92 was not able to register any passing score due to high distortion.
This means that at 20Hz one F12 has the equivalent output of roughly four KF92s, plus it has XLR inputs. The G22 has 6dB higher output at 20Hz than the F12. There is no need to use the rumble filter at all unless you are playing movies like "the edge of tomorrow" at very high levels.