The three finest measuring and sounding loudspeakers currently available!

[Purité Audio]

I am not sure what you mean by small, the Kiis are pretty much flat to 20Hz in most rooms, my(notvery )sophisticated sales technique is to set up a pair of Kii/8Cs next to the potential customers own system, enabling him/her to switch instantly between the two, the improvement in SQ is obvious.
Keith

 

[PierreV]

Can't describe it in any other way, sorry. I am neither a speaker designer nor an armchair speaker specialist. Maybe getting rid of that "small" speaker feel is what led to the BXT module? I can't say as I haven't heard them. Note that I am not against those speakers and probably will get a pair of 8Cs some time soon (for the library). It is just that I don't think at this point (again, having only heard the Kiis without the BXT module) that they are in any way an upgrade on my main configs. Pretty much flat is good, and something I aim for in my fine tuning. That being said, I feel that while it is a necessary requirement it is not a sufficient one (or all pretty flat speakers would sound and feel exactly the same, wouldn't they?)

But my main preoccupation right now is of a different nature: the subs are amazing, but the house, and particularly some of its doors aren't

 

[Purité Audio]

8Cs for the library would be great, then you will have better sound quality in your library than in your main system.
Keith

 

[PierreV]

8Cs for the library would be great, then you will have better sound quality in your library than in your main system.
Keith

I am sure it will be one of those veil-lifting, foot tapping moment.

 

[Purité Audio]

You will just hear more than ever before and bass in particular will be punchy, deep with no overhang .
Keith

 

[pierre]

PSI, are ok, just your standard active monitor, slightly more advanced that’s ATC ( what isn’t) but nothing really exciting, M2 is a two way, compression driver crossing to a bass reflex loaded cabinet , there is a new wave guide which is good.
I guess the external DSP corrects phase, step response etc?
I haven’t had a chance to play around with a pair, what can they do?
Keith

I kind of disagree: PSI A25 + associated subs are awesome: they are time aligned, flat, and powerfull, more than the kii. They don't overheat and you can push them all days. They are very hard to distinguish with the other 2 (kii or d&d). They are not cheaper on the other side. They do tricks purely on the analogue side and they have almost no latency if that's important to you.

The JBL M2 are different again : if you need high output they smoke the kii and d&d.

At a reasonable SPL they all sound the same to me. Even more basic and much cheaper Focal trio or Adam S3 are outstanding.

 

[Purité Audio]

Perhaps you are right I have never had the A25 and matching subs here, directly comparing the PSI to the Kiis and 8Cs I hear in a relatively untreated room far more resolution from the more modern speakers, if you are solely interested in SPls then buy anything for live sound.
Personally I don’t see PSI’s ‘analogue only’ as a positive selling point.
Keith

 

[pierre]

Perhaps you are right I have never had the A25 and matching subs here, directly comparing the PSI to the Kiis and 8Cs I hear in a relatively untreated room far more resolution from the more modern speakers, if you are solely interested in SPls then buy anything for live sound.
Personally I don’t see PSI’s ‘analogue only’ as a positive selling point.
Keith

I thought the OP was about best quality not sellability. PSI publish a lot of scientific data's which is not common amount speakers builders. I have no stake with them btw they are common in studios in Switzerland.

 

[Purité Audio]

It is totally about the finest sound quality, I don’t care about anything else, so when I directly compare PSI/Manger/ATC etc against Kii or the 8Cs there is no contest, PSI is just another good monitor.
If I were a loudspeaker company I would be looking to the future rather than the past.
Keith

 

[Purité Audio]

A customers set of Kii THREE/BXT modules have just arrived, this set is in light metallic silver.
https://www.puriteaudio.co.uk/kii-bxt

Keith

 

[Jaimo]

Frank ( F1 eng) is your man when it comes to the structure and resonance, but essentially nothing remains rigid at certain frequencies, best to use the driver within its passband , the motional feedback just seems a good idea, perhaps JBL will adopt it , in time.
Keith

Whats old is new again... Arnie Nudel of Infinity fame built a servo feedback LF driver /amp combo for the IRS system in the early 2000’s. Although Infinity was an independent company at the time, they went on to become a sister company to JBL in the Harman family.

https://www.stereophile.com/content/arnie-nudell-here-infinity

 

[Frank Dernie]

Whats old in new again... Arnie Nudel of Infinity fame built a servo feedback LF driver /amp combo for the IRS system in the early 2000’s. Although Infinity was an independent company at the time, they went on to become a sister company to JBL in the Harman family.

https://www.stereophile.com/content/arnie-nudell-here-infinity

Philips had a range of speakers with motional feedback a few decades ago too. They were relatively inexpensive but I recall being impressed by the one I heard.
Difficult for them to sell them in a market obsessed with brand names though, however well engineered they were. They made a cleverly isolated turntable too.

 

[Aaron Garrett]

Philips had a range of speakers with motional feedback a few decades ago too. They were relatively inexpensive but I recall being impressed by the one I heard.
Difficult for them to sell them in a market obsessed with brand names though, however well engineered they were. They made a cleverly isolated turntable too.

I think the person who designed the motional feedback speaker for Philips worked with Grimm to implement it digitally.

 

[Purité Audio]

Yes that’s correct, from the Grimm site,
The LS1s-dmf subwoofer was developed in cooperation with Rob Munnig Schmidt, who worked at Philips and ASML and was professor at the Technical University Delft. Rob explains his design motives:

"Being lifelong fascinated by precision control of motion systems and sound reproduction I never was happy with the unbalance in audio design between electronics and mechanics. On one side designers do everything to reduce distortion in electronics by means of feedback to almost unmeasurably low levels, while on the other side the real music is reproduced by electromechanical structures, called loudspeakers, without any control of their behaviour. Although many people agree that the loudspeaker is one of the most determining factors for the quality in an audio chain, strangely enough people accept that all loudspeakers have a well distinguishable character due to resonances, non-linearity, diffraction etc.

For this reason I immediately said yes when Grimm Audio asked me to design a motional feedback version of their LS1s subwoofer with a digital DSP controller, based on my experience with this principle. It covers the frequency range where control is most needed, the low frequencies around the fundamental resonance. By applying a sensitive acceleration sensor with low distortion on a rugged and powerful driver the real sound output is controlled such that the resonance disappears and distortion is significantly reduced. The effect is readily audible by its clean and dry bass where a base drum with damping blanket really gives short well controlled bumps, while organ tones to even below 20 Hz are reproduced faithfully such that you feel it rather than hear it. It is so rewarding to see people who hear the new DMF sub show real surprise when realising how much better bass reproduction can be."

Rob Munnig Schmidt

Keith

 

[sergeauckland]

Philips had a range of speakers with motional feedback a few decades ago too. They were relatively inexpensive but I recall being impressed by the one I heard.
Difficult for them to sell them in a market obsessed with brand names though, however well engineered they were. They made a cleverly isolated turntable too.

I had a pair in the early 1980s, excellent little 'speakers. I was working for Philips at the time and found them unloved in an old store room we had to clear when we moved offices. I later gave them to an impecunious friend, and they carried on for years afterwards.

S

 

[Patrick Bateman]

Yet you can't deny that active - especially DSP - has a higher objective performance ceiling. It allows steeper filters, more accurate response shaping, time delays and phase linearisation - all things that allow the input signal to be transduced more accurately. For instance, the Horbach-Keele crossover can only be readily achieved through DSP:

View attachment 24732

Yet it also promises constant directivity on both the horizontal and vertical axis with non-coaxial drivers - something that is pretty much impossible with passive. This is an objective improvement in accuracy.

Would you have any problem with DSP if it was outboard and not as tightly-integrated/proprietary or only serviceable by the manufacturer? eg. if everyone had a MiniDSP and manufacturers basically sell the intellectual property (crossovers) to be loaded into those standardised boxes?

edit: Also Keith @Purité Audio , curious to know if you might consider selling uncommon, but innovative active speakers that straddle the gap (in size and price) between KEF LS50Ws and the Grimm, Kii and DD? There are some interesting pro audio options from the continent (that I was clued onto by a German family friend) that don't seem to be well-known in the Anglophone home audio scene. For instance, some that fascinate me are the KS Digital C5-Reference - uses a SEAS coaxial like Gradient, sealed, metal enclosure, DSP crossover with phase linearisation. Have written to their engineers before and was quite impressed. There's also these guys that do sealed floorstanders with AMT tweeters and DSP crossovers, and these guys who are analog active, but have a SEAS coax monitor with very good directivity through the crossover region.

The Horbach Keele speaker only controls directivity on the vertical axis.

In order to do it on both axes, you need a 2D array, which is exactly what the Butterfield array is:

site:diyaudio.com fractal array - Google Search

You could control directivity with a one-dimensional array if the elements were sufficiently large enough. But if they were, you could have vertical spacing that's too wide. One option might be some type of oval or elliptical transducer. But a 2D array is more practical.

Note that you can "approximate" the performance of the Horbach Keele array using analog filters, as described in the link I posted.