Kii THREE versus KII THREE/BXT

[Purité Audio]

I think they are going to be awesome,

• Full-size floorstanding DSP controlled monitor speaker system.
• 12 x 6.5” woofer, 1 x 5” midrange, 1 x 1” waveguided tweeter.
• Amplification: full custom class D, 250W per drive unit, arranged in 6 groups.
• Active Wave Focusing crossover filter
• Frequency response: 20Hz (-3dB) – 25kHz, flatness ± 0,5dB (*)
• Integrated tone control
• Phase response: selectable, linear phase or minimum latency
• Protection limiters
• Controlled Directivity: 4.8dB (54Hz - 1kHz, slowly rising thereafter)
• Size: 20x120x40cm, 8”x47”x16” (WxHxD)
• Weight: 51kg (112lbs)
• Inputs: Analogue, AES/EBU, KiiLink
• SPDIF, TOSLink, USB on Kii Control
• Selectable correction for free-standing, near wall or in corner (14 positions)
• Automatic Standby Mode

But £27k for a ‘set’ KiiThree, `Kii control and BXTs.
Keith

 

[andreasmaaan]

It’s an interesting unit. I’m not sure I can see the advantage in having controlled directivity well below the Schroeder frequency unless sub placement options are restricted.

So it seems to me that, by having to sit under the mains, these units create a problem (restricted sub placement options) that they then solve, at the cost of lower efficiency and higher distortion than if the same drivers were radiating omnidirectionally and placed against room boundaries.

Or am I missing something?

 

[Purité Audio]

The BXTs extend the cardioid response of the speakers down to 20Hz , sitting them underneath creates a line source , eliminating the floor cancellation, I believe they pretty much take care of the front of the room, of course you still need to look after any room modes the low bass triggers.
Keith

 

[andreasmaaan]

The BXTs extend the cardioid response of the speakers down to 20Hz , sitting them underneath creates a line source , eliminating the floor cancellation, I believe they pretty much take care of the front of the room, of course you still need to look after any room modes the low bass triggers.
Keith

Ok I might not quite be understanding correctly.

Is the idea that they function as a line source right up to frequencies at which floor bounce from the mains might cause destructive interference? Wouldn’t this mean they would have to be augmenting (or replacing) the output from the mains up to about 300-ish Hz in typical rooms?

 

[Purité Audio]

The BXT works up to 250Hz I believe,

Keith

 

[Thomas savage]

The BXT works up to 250Hz I believe,

Keith

I see why they are so expensive now.. those shirts cant be cheap.

 

[Purité Audio]

There is a matching hat, and if you have been good this year, have you?
I will post a photograph of Bruno wearing it.
Keith

 

[Thomas savage]

There is a matching hat, and if you have been good this year, have you?
I will post a photograph of Bruno wearing it.
Keith

Next to his vivid g3's he uses at home?

 

[Purité Audio]

Bruno apparently is great friends with Laurence, obviously not good enough friends to tell him his speakers are...
Keith

 

[Thomas savage]

Bruno apparently is great friends with Laurence, obviously not good enough friends to tell him his speakers are...
Keith

Ha ha , whats bruno using at home these days Keith?

A kii ?

 

[andreasmaaan]

The BXT works up to 250Hz I believe,

Keith

That’s a bit more interesting then

 

[Purité Audio]

Ha ha , whats bruno using at home these days Keith?

A kii ?

Sadly the days of popping around to each other’s houses are long gone!
If I had to guess I would say either Audio Note UK or Devore monkey coffins, or ZU druids!
Keith

 

[FrantzM]

there is always the issue of power compression when you ask small drivers to do high bad SPL. THE BXT May be an answer to that. It frees the drivers to work on the mid bass without having to worry about the low bass with any compression. This in line with many full range speakers designs: bass reproduction is where the cost is. The BXT is however dear to the extent of doubling the price of the original design.
The same could apply to the 8&8C. It can work with external subs. In my opinion and that, based on research, the better solution. I would take as a data point, Dallasjustice heroics to tackle the bass of a speaker that by its lonesome can do 20 Hz at 110 dB. His M2 are crossed over at 180 Hz He’ll chime in if I am mistaken.

 

[Purité Audio]

The M2 can manage 20Hz at -10dB.
Keith

 

[FrantzM]

The M2 can manage 20Hz at -10dB.
Keith

Considering that the stated peak output of an M2 is 123 dB @ 1 meter ... It is clear it can play loud in the bass .. yet Dallasjustice chose to cross it over at 180 Hz ... That was the point I wanted to make.
I don't actually mind the BXT. I believe there is no substitute for displacement in the bass. I think however that it takes away from the attractiveness of the original Kii3 ... @ U$30,000 this combo is no longer the slam-dunk/Home-Run the original was.

 

[Thomas savage]

I have to say on my behalf I’m guilty here of a little idle bitching , Bruno has made a fantastic, invaluable contribution to audio imo and secretly I also admire his fashion sense..

I just don’t get these things but that’s just my fairly meaningless opinion.

 

[andreasmaaan]

That’s a bit more interesting then

Thinking this through a bit further, 250Hz is perhaps not quite high enough in frequency to be useful for most ppl (assuming the aim of the line array is to smooth out cancellations caused by the first floor reflection).

In a fairly typical domestic setup, both your ears and the upper speaker unit are likely to be about a metre off the ground. The woofer of the upper speaker might sit at around 90cm I’m guessing looking at pics of the system.

If you’re positioned at a distance of two metres from the speaker, then, the first and deepest floor reflection null will be at about 220Hz. That’s just within the range covered by the BXT, so all good. But at greater distances, that null will move up to 250Hz and higher. At 3m, for example, the null will be at about 280Hz, so well within the range of the upper speaker’s woofer.

I’d be surprised if many people with this setup are going to sit 2m or less from it. So IMO it would make more sense to allow users to shift the crossover point between 250 and 400Hz-ish. At 400Hz, you should be good to sit up to about 3.5m from the speaker without any first cancellation null from the upper speaker’s floor reflection.

Ofc at 400Hz you start flirting with some lobing issues in the woofer to mid crossover, but nothing too objectionable IME.

But in short, for anyone planning to sit more than 2m from this setup, there’s unlikely to be any advantage gained from the line array behaviour of the BXT unit.

Any error in my logic here?

 

[Purité Audio]

Santa almost ruptured himself carry these,


Keith

 

[FrantzM]

Thinking this through a bit further, 250Hz is perhaps not quite high enough in frequency to be useful for most ppl (assuming the aim of the line array is to smooth out cancellations caused by the first floor reflection).

In a fairly typical domestic setup, both your ears and the upper speaker unit are likely to be about a metre off the ground. The woofer of the upper speaker might sit at around 90cm I’m guessing looking at pics of the system.

If you’re positioned at a distance of two metres from the speaker, then, the first and deepest floor reflection null will be at about 220Hz. That’s just within the range covered by the BXT, so all good. But at greater distances, that null will move up to 250Hz and higher. At 3m, for example, the null will be at about 280Hz, so well within the range of the upper speaker’s woofer.

I’d be surprised if many people with this setup are going to sit 2m or less from it. So IMO it would make more sense to allow users to shift the crossover point between 250 and 400Hz-ish. At 400Hz, you should be good to sit up to about 3.5m from the speaker without any first cancellation null from the upper speaker’s floor reflection.

Ofc at 400Hz you start flirting with some lobing issues in the woofer to mid crossover, but nothing too objectionable IME.

But in short, for anyone planning to sit more than 2m from this setup, there’s unlikely to be any advantage gained from the line array behaviour of the BXT unit.

Any error in my logic here?

Your post is most interesting and will have me look further in the area of floor cancellation also on the Allison effect which our own DallasJustice has been talking about ...
This may explain the issue of "large" speakers versus the so-called sub satellite configurations... My contention has been for years that sub + satellite even when playing loud and measured to be flat (or slopping down if you want people !! ) still never sound like big speakers ...
I presently have 3 JBL LSR 308 and 2 LSR 305 plus 4 subs in my experimental HT... These LSR and the subs play too loud for me to bear, I did measure 110 db yesterday on a train crash .. never to try that at home again.. my ears actually felt pain... briefly ... no tinnitus but I am warned !! These however never sound "big" . The system is full range, plays nice from 20 to 20 Khz no issue , no compression artifacts that I care for .. yet they will never fool anyone that they're listening to a large speaker .. This may be caused by this Allison effect ... sI am peculating wildly, being ignorant but I will learn ... There is something about how the midbass is reproduced that seems to contribute to the sense of "bigness'

Stay tuned. :0
Happy Holidays!!

 

[Thomas savage]

Santa almost ruptured himself carry these,


Keith

Will the mother in law fits in one of these ?

Lock away a few family members this Christmas.