KEF Reference 8b vs KF92

[JimA84]

The specs on these seem a bit wonky, as do the prices.

To believe KEF's specs, you can buy a nearly identical KF92 for $2,000 that reproduces 11 Hz at 100dB and weighs half as much as the Reference 8b that only goes to 24 Hz at 90 dB and costs $7,500. But the 8b does offer a XLR input.

Is the 8b really that poor?

If this is true, why haven't they upgraded the 8b to equal the KF92?

I would chalk it up to exaggerated specs for the KF92 but I have received input from reliable sources that the KF92 actually delivers 100dB at about 10 Hz.

So how can the $7500 8b weigh twice as much and only deliver 24 Hz?

I realize it's a much older design, but why not upgrade it then?

 

[Morpheus]

Probably has to do with lower distortion, more headroom at a bit higher frequencies, and finish quality. Getting deep, dynamic and high output bass at a very low distortion is an expensive endeavour, to get to where the KF is, it very probably compromised somewhere, and I would bet distortion.

 

[Ciobi69]

Take another subwoofer they are too expensive, i got kef myself and diy sub or you can buy arendal they are good lookkng and way more Performant

 

[JimA84]

Probably has to do with lower distortion, more headroom at a bit higher frequencies, and finish quality. Getting deep, dynamic and high output bass at a very low distortion is an expensive endeavour, to get to where the KF is, it very probably compromised somewhere, and I would bet distortion.

I think maybe it's due to legacy product from a different business unit. Kind of like IBM mainframe. Anyway, rather than speculation I asked KEF straight up, so I will wait on their response rather than speculate at their expense.

 

[ban25]

The specs on these seem a bit wonky, as do the prices.

To believe KEF's specs, you can buy a nearly identical KF92 for $2,000 that reproduces 11 Hz at 100dB and weighs half as much as the Reference 8b that only goes to 24 Hz at 90 dB and costs $7,500. But the 8b does offer a XLR input.

Is the 8b really that poor?

If this is true, why haven't they upgraded the 8b to equal the KF92?

I would chalk it up to exaggerated specs for the KF92 but I have received input from reliable sources that the KF92 actually delivers 100dB at about 10 Hz.

So how can the $7500 8b weigh twice as much and only deliver 24 Hz?

I realize it's a much older design, but why not upgrade it then?

If you want real measurements, look to Erin's review:

It's 82 dB at 20 Hz. The KF92 is severely limited in output below 40 Hz. Yes KEF reports the bottom end of the frequency response as 11 Hz and the maximum output as 110 dB, but obviously, not at the same time. As someone who has owned a KF92 for years, it's a modest sized sub with decent output for the size. Do I want it to play at 11 Hz? No. In fact, I don't want it to play anything below 18 Hz at the lowest.

 

[JimA84]

The specs on these seem a bit wonky, as do the prices.

To believe KEF's specs, you can buy a nearly identical KF92 for $2,000 that reproduces 11 Hz at 100dB and weighs half as much as the Reference 8b that only goes to 24 Hz at 90 dB and costs $7,500. But the 8b does offer a XLR input.

Is the 8b really that poor?

If this is true, why haven't they upgraded the 8b to equal the KF92?

I would chalk it up to exaggerated specs for the KF92 but I have received input from reliable sources that the KF92 actually delivers 100dB at about 10 Hz.

So how can the $7500 8b weigh twice as much and only deliver 24 Hz?

I realize it's a much older design, but why not upgrade it then?

I talked at length with a KEF factory rep about this. He said that the Reference 8b is an older design that was cutting edge at the time, but has been eclipsed by the KF92 and KC92 in terms of bass extension.

Also, the Reference 8b is a handmade product produced in England with superior quality materials and extreme quality testing.

The KF92 and KC92 are factory made in China.

He said that the main reason for keeping the Reference 8b on sale is for people who have existing KEF Reference speaker sets and want a matching product.

This seems to be a reasonable explanation for the disparity in price and published specifications.

 

[ban25]

I talked at length with a KEF factory rep about this. He said that the Reference 8b is an older design that was cutting edge at the time, but has been eclipsed by the KF92 and KC92 in terms of bass extension.

Also, the Reference 8b is a handmade product produced in England with superior quality materials and extreme quality testing.

The KF92 and KC92 are factory made in China.

He said that the main reason for keeping the Reference 8b on sale is for people who have existing KEF Reference speaker sets and want a matching product.

This seems to be a reasonable explanation for the disparity in price and published specifications.

Good to know. I'm eager to see measurements of the KC92 to see if there's anything beyond some new silicone gasket and maybe onboard DSP.

 

[Vacceo]

Good to know. I'm eager to see measurements of the KC92 to see if there's anything beyond some new silicone gasket and maybe onboard DSP.

Same size on woofers and cabinet, same amps...

Probably the differences are minimal if they even exist.

 

[Mnyb]

The improved driver surround migth do something for distortion, but we don’t hear distortion very well at low bass frequencies ? Maybe there are more small improvements in the drivers ?

I’m also curious maybe the CEA2010 values gets improved, as they are distortion limited .
The CEA2010 values are not a limit it tells you that the sub can put out frequency at some level of distortion.
But it can probably play a bit louder if you allow more distortion .

But as you say it’s the same size , physics rules if not excursion has been improved a lot they ought to be similar .

 

[JimA84]

Good to know. I'm eager to see measurements of the KC92 to see if there's anything beyond some new silicone gasket and maybe onboard DSP.

As far as I can tell the only change that might have a minor effect on sound from the KF92 to the KC92 is the P-Flex "Origami" surround which is reminiscent of ELAC's DS1200 "rumpled" surround.

The other changes are usability (genuine always on and also 12V trigger), white color choice, and the LFE mode setting has been moved to the crossover knob instead of a slide switch.

Otherwise the two are nearly identical.

Since the specs haven't changed I assume the main effect of the new surround is less distortion at long extension.

 

[ban25]

Since the specs haven't changed I assume the main effect of the new surround is less distortion at long extension.

Indeed. I have no complaints as to how the KF92 sounds, so any reduction in distortion wouldn't be sufficient justification to upgrade. It's possible the KF92 will be going on sale soon to clear out old stock, so it could be a good opportunity for those already considering it...

 

[JimA84]

Yes, you would be getting a good bargain.