These subwoofers have recently been revealed by Kef with some extraordinary claims and some very interesting technologies. Seem to be too good to be true. Thoughts?
Well, those claims are ridiculous, that i would not trust from most speaker brands. But it's Kef, who mostly know what they are doing so i'm curious how close the reality is to the claims... But an F3 of 11hz at that volume out such a small speaker, i don't think that is possible to be honest.
Exactly what I was thinking. It may well produce a phenomenal amount of well controlled bass for a small package but a -3db Point at 11Hz Who will do the first independent testing?
The Devialet Phantom is claiming similar specs which personally I’d have to experience directly to have any chance of believing.
The Devialet Phantom is claiming similar specs which personally I’d have to experience directly to have any chance of believing.
It's possible to get 1Hz out of a 1" tweeter. Just really quietly.
The SPL at 11Hz will be limited by the mechanical displacement of the drivers. A pair of 6" drivers would each need to move 12.7mm one-way to produce 80dB at 11Hz, so if you ran an 83dB (nominal) sweep and limited excursion to 12.7mm, then the -3dB point would indeed be 11Hz.
The motor etc looks interesting, and they've incorporated some feedback. Should be a nice little box, and if I was in the market, I'd probably pick up a couple.
Chris
The SPL at 11Hz will be limited by the mechanical displacement of the drivers. A pair of 6" drivers would each need to move 12.7mm one-way to produce 80dB at 11Hz, so if you ran an 83dB (nominal) sweep and limited excursion to 12.7mm, then the -3dB point would indeed be 11Hz.
The motor etc looks interesting, and they've incorporated some feedback. Should be a nice little box, and if I was in the market, I'd probably pick up a couple.
Chris
Read between the lines!
Max SPL 105 dB (frequency not specified)
80dB at 20Hz
11 Hz extension
OK, lets put it in normal speak...
Frequency response 20 to 200Hz +0 / -25dB
Ya see, the specs are incomplete so yeah, it has a max output of 105dB and it might be at 80 Hz but that does not mean it will do it down low because there is not chart. As Chris put it, a 25mm dome tweeter will do 11 Hz as long as there is no specification. I know my sub will move around when I play Bass I Love You which has 8Hz tones--but I tuned it to 20Hz and won't claim it goes down to 8Hz. Heck, if I changed the amp and removed the high pass filter I bet it will move at 1 Hz but not at a level I could humanly detect.
OK, we do have one spec to play with--80Hz at 20 Hz. Considering it is a sealed subwoofer, those drop at around 12dB per octave so safe to say it would be 70dB at 11 Hz? Can you detect that--humans won't.
All sorts of way to play games with specifications--that is why you need either a chart or F-3dB, F-6dB at the limit. Some companies pull out F-10dB as "usable" or something.
Realistically, that 10 inch cube is a lifestyle product and the people that purchase it generally don't know/don't care about performance as they want the smallest thing they can squeeze in that makes sound.
Can't deny it! There is an audio company called Bose that came out with their little 2.5 inch full ranges in plastic boxes with a small "bass module" that had an F-3dB point at 42Hz--but at least they didn't call it a sub. Heck, Bose didn't claim much of anything except a power handling number and the dimensions. Bose sold millions of those things as a lifestyle product and many people were happy to have tiny speakers.
As we all know, some specs are fantasy as in those $14 chip amps that have 700 watts peak all from a 12V 2.5 amp wall wart. Plenty of car audio things that claim thousands of watts for $35 on Ebay, Alibaba and others but that type of marketing has been around for decades. Anyone remember boom boxes with 1050 watts PMPO? Not sure how you get that kind of watts out of something that runs on 6 C alkalines so maybe, just maybe they measure it in an alternate dimension?
The annoying thing is KEF resorted to that hype marketing style, not sure why they would do that as they don't have to. Yes, the lifestyle audio market is big--most likely bigger than the typical audio market and they have to hype the thing to the moon because marketing. Eventually, somebody is going to measure it to a known standard and yet again, physics will win but that thing is not aimed at the HT/audio fan market and we would not buy it in the first place.
I know when Bose hit a home run with the little cube speakers their other speaker lines slowly faded away. Maybe KEF is going that direction, go for the lifestyle market and adjust their line as required. You should know that KEF is not an independent audio company, they were bought out back in 1992 by a holding company so maybe their masters are moving in a different direction? I dunno, my crystal ball has a virus...
As always, check the exact specs, never assume anything and always, always, always get third party measurements before buying audio gear. Realistically, the little guy at 80dB at 20Hz is nothing note worthy and making a sub opposed has been around for many decades. I do find the different sized voice coils, different sized spiders and overlapping voice coils to be an interesting challenge to keep them balanced with weight, the compliance and thermals being different. The distortion measurements should give the answer to see if they achieved what the marketing promises. We shall see!
Max SPL 105 dB (frequency not specified)
80dB at 20Hz
11 Hz extension
OK, lets put it in normal speak...
Frequency response 20 to 200Hz +0 / -25dB
Ya see, the specs are incomplete so yeah, it has a max output of 105dB and it might be at 80 Hz but that does not mean it will do it down low because there is not chart. As Chris put it, a 25mm dome tweeter will do 11 Hz as long as there is no specification. I know my sub will move around when I play Bass I Love You which has 8Hz tones--but I tuned it to 20Hz and won't claim it goes down to 8Hz. Heck, if I changed the amp and removed the high pass filter I bet it will move at 1 Hz but not at a level I could humanly detect.
OK, we do have one spec to play with--80Hz at 20 Hz. Considering it is a sealed subwoofer, those drop at around 12dB per octave so safe to say it would be 70dB at 11 Hz? Can you detect that--humans won't.
All sorts of way to play games with specifications--that is why you need either a chart or F-3dB, F-6dB at the limit. Some companies pull out F-10dB as "usable" or something.
Realistically, that 10 inch cube is a lifestyle product and the people that purchase it generally don't know/don't care about performance as they want the smallest thing they can squeeze in that makes sound.
Can't deny it! There is an audio company called Bose that came out with their little 2.5 inch full ranges in plastic boxes with a small "bass module" that had an F-3dB point at 42Hz--but at least they didn't call it a sub. Heck, Bose didn't claim much of anything except a power handling number and the dimensions. Bose sold millions of those things as a lifestyle product and many people were happy to have tiny speakers.
As we all know, some specs are fantasy as in those $14 chip amps that have 700 watts peak all from a 12V 2.5 amp wall wart. Plenty of car audio things that claim thousands of watts for $35 on Ebay, Alibaba and others but that type of marketing has been around for decades. Anyone remember boom boxes with 1050 watts PMPO? Not sure how you get that kind of watts out of something that runs on 6 C alkalines so maybe, just maybe they measure it in an alternate dimension?
The annoying thing is KEF resorted to that hype marketing style, not sure why they would do that as they don't have to. Yes, the lifestyle audio market is big--most likely bigger than the typical audio market and they have to hype the thing to the moon because marketing. Eventually, somebody is going to measure it to a known standard and yet again, physics will win but that thing is not aimed at the HT/audio fan market and we would not buy it in the first place.
I know when Bose hit a home run with the little cube speakers their other speaker lines slowly faded away. Maybe KEF is going that direction, go for the lifestyle market and adjust their line as required. You should know that KEF is not an independent audio company, they were bought out back in 1992 by a holding company so maybe their masters are moving in a different direction? I dunno, my crystal ball has a virus...
As always, check the exact specs, never assume anything and always, always, always get third party measurements before buying audio gear. Realistically, the little guy at 80dB at 20Hz is nothing note worthy and making a sub opposed has been around for many decades. I do find the different sized voice coils, different sized spiders and overlapping voice coils to be an interesting challenge to keep them balanced with weight, the compliance and thermals being different. The distortion measurements should give the answer to see if they achieved what the marketing promises. We shall see!