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

waynel

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That differs from several sources like Sparechange stating that he got 100 dB from a pair of Kef KF92's at 10 Hz.
This is an objective standardized measurement and accounts for distortion, not some random guys measurement in a random room.
Rythmik subs are good legacy models, but modern technology has way eclipsed their potential, although at significantly higher cost.
I honestly don't know what you are talking about, and neither do you.
The majority of published reviews confirm that the KF92 is capable of serious response below 16 Hz at high volume.
False, It has been measured and cannot pass CEA-2010 at 16Hz and was only able to achieve 86dB at 20Hz
You can argue anything but the scientific facts are clear.
This is true, but the facts are not in favor of your argument
 

jhaider

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One of my issues is that having been home invasion robbed I'm not keen on inviting a team of sketchy installers into my home to install a Wilson Audio sub that weighs hundreds of pounds only to return later to uninstall everything they can.

I don’t know where you are in the world or if you are dealing primarily with aesthetic constraints couched above as weight constraints, but if you’re looking for big bass at relatively lower mass (for the cabinet size) PSA has interesting options. They use modern neo-magnet drivers derived from pro audio drivers (or in some cases stock pro audio drivers) instead of drivers with giant mud magnets. So the drivers weigh a third to a quarter as much, while not giving up any motor strength.

I don’t use them personally, but I dig their approach.

That said, I think there’s some disconnect here between outdoor extension/output and small room extension/output. Yes, the former (if done per the relevant standard) has the huge benefit of results comparable across reviewers. But the CEA numbers don’t account for modes in a small room. So a sub that is objectively lesser may end up being just fine in a small room for a given listener.
 

sigbergaudio

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You guys know you can’t hear 16hz right? :) even 20hz at the levels these small subs can reproduce is almost inaudible unless you’re playing a pure sine sitting right next to it.
 

waynel

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You guys know you can’t hear 16hz right? :) even 20hz at the levels these small subs can reproduce is almost inaudible unless you’re playing a pure sine sitting right next to it.
I can feel the 16Hz pedal tones with my medium sized subs (Rythmik F18s) while I'm sure it's not possible with tiny subs , which is why I'm recommending larger subs for organ music.
 

Tokyo_John

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You guys know you can’t hear 16hz right? :) even 20hz at the levels these small subs can reproduce is almost inaudible unless you’re playing a pure sine sitting right next to it.

16.35 Hz is the C0 note at the very bottom of the scientific octave scale, one octave lower than the lowest C on a typical piano (C1)...

Scientific_pitch_notation_octaves_of_C.png


...C0 is one octave lower than the lowest C1 pedal note on Bach's Passacaglia and Fugue in C Minor for organ (note the one octave decrement under the clef)...

1707348390091.png


...go ahead and listen to the first passage, just 20 seconds out of your life (that C1 note anchors the entire piece), and think about what a C0 note would sound/feel like...it is more like an earthquake, than a note. But with enough power to move air in a room, it can certainly be felt.
 

JimA84

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I don’t know where you are in the world or if you are dealing primarily with aesthetic constraints couched above as weight constraints, but if you’re looking for big bass at relatively lower mass (for the cabinet size) PSA has interesting options. They use modern neo-magnet drivers derived from pro audio drivers (or in some cases stock pro audio drivers) instead of drivers with giant mud magnets. So the drivers weigh a third to a quarter as much, while not giving up any motor strength.

I don’t use them personally, but I dig their approach.

That said, I think there’s some disconnect here between outdoor extension/output and small room extension/output. Yes, the former (if done per the relevant standard) has the huge benefit of results comparable across reviewers. But the CEA numbers don’t account for modes in a small room. So a sub that is objectively lesser may end up being just fine in a small room for a given listener.
I have looked at PSA, and other neo magnet subs. I want something I can move by myself with some effort that will deliver clean response as close as possible to 16 Hz. Note that I had a pair of full range speakers in 1969 that would deliver clean bass down to 20 Hz at -3 dB.
And I could move them by myself.

I don't really have a WAF because I only marry women who appreciate my tastes.

It's simply not that hard to do it, it's just that most companies don't get it.

Must be Harvard Business School prevailing over MIT.
 

sigbergaudio

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I have looked at PSA, and other neo magnet subs. I want something I can move by myself with some effort that will deliver clean response as close as possible to 16 Hz. Note that I had a pair of full range speakers in 1969 that would deliver clean bass down to 20 Hz at -3 dB.
And I could move them by myself.

I don't really have a WAF because I only marry women who appreciate my tastes.

It's simply not that hard to do it, it's just that most companies don't get it.

Must be Harvard Business School prevailing over MIT.

The question isn't really if the sub hits -3dB at 20hz or 16hz, but how loud you expect it to do it.
 

JimA84

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I can feel the 16Hz pedal tones with my medium sized subs (Rythmik F18s) while I'm sure it's not possible with tiny subs , which is why I'm recommending larger subs for organ music.
Larger isn't better. At least not in a reasonable room. Of course you could go with Wilson Audio. "Thor's Hammer." Kind of like the EV Patrician.

The church I grew up in had a real pipe organ donated by a member who was a building contractor. It had the real 16 Hz pipes. And our musical director was classically trained and our organist knew how to play it.

So I've enjoyed the real thing.

And you don't need a 36 inch speaker to reproduce it at reasonable volume.

I have the scientific and engineering degrees and experience to know this.

I just want some people since Sunfire to step up instead of making excuses.

Sunfire did it, and with the technology since, it's possible.

Of course an example of "progress" is how we went from a cell phone camera that would produce a perfect photo of the moon and stars to one that produces a shapeless blob unless you buy the "ultra" model, and even then sucks compared to an old Sony Alpha camera.
 

jhaider

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I have looked at PSA, and other neo magnet subs.

Note that neo isn’t always lighter. Aurasound’s bass drivers - IMO still unsurpassed - are in the same weight class as long stroke mud magnet drivers. The underhung motor has tons of steel in it. Of course with mud magnets they’d weigh possibly close to double their weight with neo.

I want something I can move by myself with some effort that will deliver clean response as close as possible to 16 Hz. Note that I had a pair of full range speakers in 1969 that would deliver clean bass down to 20 Hz at -3 dB.
And I could move them by myself.

I think there may be some rose-colored nostalgia there. They may have claimed such but in 1969 measurement gear, let alone drivers and amps, weren’t sufficient to make it meaningful. That said, something like a KEF 92 will handily exceed those unnamed 1969 man-portable speakers in bass output. And way better than those Sunfire shoeboxes, which were awful sounding devices (very long stroke drivers with no inductance mitigation in the motor) and probably turned a lot of music first folks off of subwoofers.
 

sigbergaudio

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My speakers in 1969 hit 20 Hz at around 96dB.

Room gain will help of course. The Kef K92 was measured by Erin, the CEA2010 measurements show 85dB at 20hz. However this is outdoors, so you will see significant room gain.
 

JimA84

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Note that neo isn’t always lighter. Aurasound’s bass drivers - IMO still unsurpassed - are in the same weight class as long stroke mud magnet drivers. The underhung motor has tons of steel in it. Of course with mud magnets they’d weigh possibly close to double their weight with neo.



I think there may be some rose-colored nostalgia there. They may have claimed such but in 1969 measurement gear, let alone drivers and amps, weren’t sufficient to make it meaningful. That said, something like a KEF 92 will handily exceed those unnamed 1969 man-portable speakers in bass output.
Did I not adequately explain that I am a scientist and engineer who was a member of the IEEE? You seem to ignore my experience and that at one point I worked for NAVSEA in submarine sonar and could actually measure things with equipment you only dream about. I have no reason to inflate anything.

The fact is that it is possible to reproduce 16 Hz at least around 96 dB in a modest room without speakers that occupy 2/3 of the room.

Indeed I could do it with some sonar transducers that would likely turn your brain into jello at sound levels you cannot imagine.

This pissing contest is silly. Unless you have something useful to contribute, I am done.
 

waynel

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Did I not adequately explain that I am a scientist and engineer who was a member of the IEEE? You seem to ignore my experience and that at one point I worked for NAVSEA in submarine sonar and could actually measure things with equipment you only dream about. I have no reason to inflate anything.

The fact is that it is possible to reproduce 16 Hz at least around 96 dB in a modest room without speakers that occupy 2/3 of the room.

Indeed I could do it with some sonar transducers that would likely turn your brain into jello at sound levels you cannot imagine.

This pissing contest is silly. Unless you have something useful to contribute, I am done.
I am also an IEEE member as are many on this board. We are trying to guide you to a high performance well measuring sub and away from subjective YouTube reviewers and anecdotes. Sweetchaos did a great job collecting sub measurements for comparison. I suggest you start there rather than relying on KEFs marketing. (Btw , I respect KEF and think they make good speakers and I even own a pair, just pointing out that the KF92 measures poorly for its cost and is not even competitive for its size)
 

bo_knows

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Did I not adequately explain that I am a scientist and engineer who was a member of the IEEE? You seem to ignore my experience and that at one point I worked for NAVSEA in submarine sonar and could actually measure things with equipment you only dream about. I have no reason to inflate anything.

The fact is that it is possible to reproduce 16 Hz at least around 96 dB in a modest room without speakers that occupy 2/3 of the room.

Indeed I could do it with some sonar transducers that would likely turn your brain into jello at sound levels you cannot imagine.

This pissing contest is silly. Unless you have something useful to contribute, I am done.
Hi JimA84,

Take a look at my post #96 and you will see that the KEF KF92 subwoofer goes down flat to 15Hz and it's not sitting on the floor but on the isolation platform. My floor is the engineering wood glued to the concrete foundation. I'm not sure how accurate the umik-2 microphone is but I will assume that most members here are probably using it for their REW measurements. My MAIN CONSTRAINT was the space around the speakers and room to place anything larger than KF92. Is it expensive for what it "offers", I guess yes.
I don't regret it one bit. Works great for me and in my room. :)
 

PeterMod

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I recently purchased and installed two KEF KF92 subs, rather than something larger and measuring better. I have space issues in my listening room, so I tried to get something reasonable that fit and is within the visual design of our space. I had to put the KEF subwoofers in the locations available to them, so I couldn't try to get more from them in different locations.

I previously had a single Definitive Technology Super Cube I 12" sub with 500 watts, which had two passive radiators. The overall size of the box is only 1" larger per dimension than the new KEFs.

I use Audyssey with my Denon AVR to measure and set levels. I don't have anything more sophisticated than that. I cross over the low frequencies at 50 Hz with the dial on the sub itself.

I listen to a wide range of music, and I watch movies that use the lower frequencies. Subjectively, the two KEF KF92 subs make for a more uniform listening in the room, but the low frequencies' impact do not match the previous single Definitive Technology Super Cube I. The single subwoofer had widely varying responses, aka room modes, all over the place, though, and getting loud meant getting distorted.
In my room, the low frequencies are present from the KEF KF92, but not at the levels I previously had.

I'm also still pleased with the change I made. If I had the space and didn't have the visual impact concerns, though, I would have gotten something larger, and less expensive.
 

Vacceo

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You guys know you can’t hear 16hz right? :) even 20hz at the levels these small subs can reproduce is almost inaudible unless you’re playing a pure sine sitting right next to it.
Yet, It can be felt. If you like horror films, the infrasonics are an integral element of many sound mixes.
 

sigbergaudio

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Yet, It can be felt. If you like horror films, the infrasonics are an integral element of many sound mixes.

Yes, but the point was that it then requires quite a bit of air to move for you to actually make that happen, and/or have the subwoofer pretty close. :)
 

Vacceo

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Yes, but the point was that it then requires quite a bit of air to move for you to actually make that happen, and/or have the subwoofer pretty close. :)
Absolutely. Small subwoofers will bring infrasonics, yes; but do not expect your ribcage to rattle.

I'm sure a lot of people would choose not to have a subwoofer the size of a washing machine if it could be avoided, yet those subwoofers (an admin over here has a JL Gotham, I think) exist for a reason.
 

phoenixdogfan

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You know EAC recently reviewed and measured this sub. Turns out it's handily outperformed by BOTH the SVS SB 2000 AND the SVS SB 1000. Moreover, it costs 2.5-3X what the OG SB 2000 costs. The SB 2000 will hit 20hz at 95 db, the KF 92 will hit it at 86 DB. The KF 92 is slightly bigger, around an additional 1.5" on each dimension.

As someone who has bought KEF three times (LS 50, LS 50 Meta, HTC 3001 SE), I would definitely recommend keeping the plastic in the wallet on this one--even if some retailer offers a KF 92 on clearance. It will do 20 hz barely, and I can not imagine 16 hz being anything other than inaudible and unimpactful. It's really just a 30 hz detached, powered woofer. To be worthy of the name, a sub should be able to hit 20hz at 100 db measured at a distance of 1 meter.

To get the kind of air moving required to get a viscera shaking 16 hz sub response, be prepared to pay thousands of dollars, and put up with some very large displacement boxes. Not even the engineers at KEF can repeal the laws of physics. And IDK what music could be played either. As already mentioned, the C1 pedal of the Bach Tocata and Fugue in D Minor hits at 32 hz. Maybe some Techno music? Recorded material at that level, at least for music, is nearly if not completely nonexistent. Maybe movie sound effects? Perhaps, it might be might make sense in an all out attempt at a summit level home theater, but aside from that, a 16 hz sub doesn't seem to be all that useful anywhere.
 
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Vacceo

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You know EAC recently reviewed and measured this sub. Turns out it's handily outperformed by BOTH the SVS SB 2000 AND the SVS SB 1000. Moreover, it costs 2.5-3X what the OG SB 2000 costs. The SB 2000 will hit 20hz at 95 db, the KF 92 will hit it at 86 DB. The KF 92 is slightly bigger, around an additional 1.5" on each dimension.

As someone who has bought KEF three times (LS 50, LS 50 Meta, HTC 3001 SE), I would definitely recommend keeping the plastic in the wallet on this one--even if some retailer offers a KF 92 on clearance. It will do 20 hz barely, and I can not imagine 16 hz being anything other than inaudible and unimpactful. It's really just a 30 hz detached, powered woofer. To be worthy of the name, a sub should be able to hit 20hz at 100 db measured at a distance of 1 meter.

To get the kind of air moving required to get a viscera shaking 16 hz sub response, be prepared to pay thousands of dollars, and put up with some very large displacement boxes. Not even the engineers at KEF can repeal the laws of physics. And IDK what music could be played either. As already mentioned, the C1 pedal of the Bach Tocata and Fugue in D Minor hits at 32 hz. Maybe some Techno music? Recorded material at that level, at least for music, is nearly if not completely nonexistent. Maybe movie sound effects? Perhaps, it might be might make sense in an all out attempt at a summit level home theater, but aside from that, a 16 hz sub doesn't seem to be all that useful anywhere.
There is a very easy to find case of infrasonics used in film: the very start of Edge of Tomorrow.
Fury, with the tanks' main guns firing, also has some nice infrasonics going around.

Classic horror films such as Hellriser have sprinkled infrasonics for extra angst.

I agree, however, that if you want that thumping on you, it will be expensive.
 
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