Celuaris SPK5 Purifi Review (speaker)

[Zvu]

"No bass" is just bad tunning. No Seas 6.5" will compete with Purifi 6.5" and win. Seas use metal cones (hard cone breakup) and paper (flawed the way they use it), have higher distortion due to worse motor structure and are more expensive. ScanSpeak 18WU on the other hand might have something to offer.

 

[Massimo]

It’s a concept design from Purifi to showcase to manufactuers. The member here uses the public plans to build them, and it’s ~£2000, mainly due to the tweeter costing ~$900/pair and the woofers costing ~$700/pair (these are not using bulk discounts).

I speculated before, but I really think they went with this underwhelming tweeter (for the money), because it is an AMT and it’s expensive. So, it is meant to showcase that it can be crossed over quite high (>3kHz) without much detriment and that is belongs in exotic/expensive setups.

No knock to the member who sells them, as he is just following plans and meeting demands for those that want it, but for a similar price, Rick (Selah Audio) sells their Purezza, which is a 2-way bookshelf using this woofer with a ribbon/planar tweeter that is much better (with a cabinet that looks professional), Erin measured them, and he liked them more than Dennis’ BMR If I recall (which just goes to show how great the BMR is, getting compared to a speaker >1.5x more expensive):
https://www.erinsaudiocorner.com/loudspeakers/selah_audio_purezza/

Purifi selected the AMT tweeter because it had the lowest measured current distortion and iron hysteresis of all the tweeters they tested.

 

[YSC]

Is it illusion or something? I looked at it on phone and the FR shape looks pretty similar to what KEF R3

 

[FeddyLost]

I still suppose that this driver was done for evolution of Kii 3 project = suited for dsp-controlled power-hungry arrays in sealed enclosure with aggressive FR shaping..
Only in such situation it really gets some reason to exist.
Otherwise it looks like a really bad joke at classic 2-way design of small bookshelves.
I don't understand why one would really make reference passive speaker like this when there are Purezza and Puri-bliss solutions.

 

[q3cpma]

Seas use metal cones (hard cone breakup)

Who cares about breakup at frequencies higher than 20 kHz?

and paper (flawed the way they use it)

Mind explaining? Otherwise, I also think ScanSpeak is generally better.

I still suppose that this driver was done for evolution of Kii 3 project = suited for dsp-controlled power-hungry arrays in sealed enclosure with aggressive FR shaping.

I thought its Fs made it almost exclusively for cabinets with a resonant mechanism.

 

[FrantzM]

gents, how is it that this speaker scores better than the JBL 708P? The FR doesn't look as smooth.

+1

Looking at the FR and data from the review, I wouldn't expect this either. Thinking out loud here: Some parameters may need to be added/juggled/removed/weighed differently on/to the preference score calculations. This "Preference Score" is often confusing to me (and others, I'll bet).
I am an ignoramus and respect designers of the caliber of Bruno Putzey's ... Yet , I think Purifi should provide better reference designs, in my view. The way the driver is used in this "reference Design" doesn't seem optimal to me ... BTW I prefer sealed designs, to me bass, from 0 to 80 Hz should be left to subwoofers in separate boxes, not to ports... I would like to see others with qualifications chiming in.
I, frankly would like to see what people at Genelec, Neuman, etc would do with such a driver, if indeed it has some inherent design advantages...

 

[ZööZ]

Just a noob question but how much of the low distortion is due to the early roll off as it seems to become worse on louder levels. So if the cabinet would be treated so that the roll off wouldn't start as early wouldn't it just make the distortion rise or would it just bring out more of that undistorted bass?

 

[Deleted member 65]

@mitchco reviewed the SPK4 and was duly impressed by its performance incl bass. Where did Purifi go wrong with the updated/improved SPK5 version?

 

[Lbstyling]

Is it illusion or something? I looked at it on phone and the FR shape looks pretty similar to what KEF R3

Designed for European houses with brick walls. It typically fills in the dip on the low end. Jack confirms as much in a interview somewhere. Their larger speakers even have swappable port tubes for the customer to change depending on the kind of building construction they will be in.

 

[Francis Vaughan]

"No bass" is just bad tunning. No Seas 6.5" will compete with Purifi 6.5" and win. Seas use metal cones (hard cone breakup) and paper (flawed the way they use it), have higher distortion due to worse motor structure and are more expensive.

The problem with this driver is that its TS parameters make better tuning something of a trial. It needs a port of near ridiculous size to effect a good bass alignment. It is better paired with a passive radiator. Or just bite the bullet and put it in sealed enclosure, in which it works well alignment-wise, and pair it with a sub-woofer.

Seas are a bit of a polarising speaker manufacturer. They tread a different path to the other Scandinavian designers. Whether they "win" versus Purifi or indeed another design house is not a binary question.

 

[thewas]

Ic, but then would it be better when in a pair have different side offset so the image is more balanced?

Yes, such loudspeakers are usually sold in mirror symmetric pairs.

 

[thewas]

gents, how is it that this speaker scores better than the JBL 708P? The FR doesn't look as smooth.

My guess is that mainly due to 2 factors, the JBL has a large wiggle in the mids and also its PIR (like also its sound power) shows kind of constant directivity pattern in the highs (that is dropping till around 2 kHz and then rather constant) which gets more punished in the Harman score compared to a continuously linearly dropping FR.

 

[Lorenzo74]

side note: any reason the tweeter is located on the side rather than in the middle?

Just guess:
1) to reduce diffraction distortion by having tweeter to cabinet edge distance spread over 2 values (horizontally) instead of one.
2) to optimize-reduce front baffle height

 

[tktran303]

There’s nothing unusual about the T/S parameters of this PTT6.5 midwoofer.

It just likes small boxes. Which is a better problem to have, than one that needs an enormous box.

Of course, the downside of that is that you might run out of room for a port.

That’s why Purifi needed a folded port to tune it to 30Hz.

Selah Audio chose a more reasonable 38Hz using a larger passive radiator.

You can put it in sealed box; 1/4 to 3/8cu ft sealed.
You can put it in a 0.7cu foot enclosure tuned to 35Hz, with a 2” x 8” flared port.
I put it in 0.7cu ft, tuned to 39Hz, with a bigger but longer port, for a punchier midbass.

So Lots of options- sealed, vented or PR.

And pro’s and cons with each approach.

Engineering is a balance.

The only downside, is the lower than average sensitivity.

But then Purifi recently released a higher sensitivity model, albeit with normal Xmax.

 

[IVX]

strange to see the slop down from 10kHz to 20kHz for Heil planar tweeter, usually such driver has way more linear resplnse up to 40kHz.

 

[Zvu]

Who cares about breakup at frequencies higher than 20 kHz?

We are comparing midwoofers. Who mentioned 20kHz ?

I did wrote about importance of >20kHz but in another thread few months ago.

 

[Zvu]

... It is better paired with a passive radiator.

My point is that the only way to use Purifi is with PR, and i wrote that even before Purifi mentioned that they will offer passive radiator of their own.

http://www.htguide.com/forum/showth...s-D-amplifiers&p=632398&viewfull=1#post632398

.... Whether they "win" versus Purifi or indeed another design house is not a binary question.

It is in my opinion when we compare it with Purifi 6.5". We can compare Purifi with any 6.5" woofer Seas have in their offer. The data is out there and it doesn't look good for Seas.

 

[q3cpma]

We are comparing midwoofers. Who mentioned 20kHz ?

I did wrote about importance of >20kHz but in another thread few months ago.

Oh, sorry, thought you were talking about tweeters, for some strange reason. I'm also partial no treated paper in general (which Seas also does), but some of their and SB designs, seem to move the breakup for enough to not matter.

 

[uwotm8]

Seas use metal cones (hard cone breakup) and paper (flawed the way they use it)

Whatever happens in theory, only the result matters.

and are more expensive

Oh rly? Typical Revelators and Excels cost 1.5 to 2 times less (as far as we don't need graphene)
https://www.madisoundspeakerstore.com/approx-6-7-woofers-scanspeak/
https://www.madisoundspeakerstore.com/approx-6-7-woofers-seas/
https://www.madisoundspeakerstore.com/approx-6-7-woofers-purifi/

But honestly I think that "alien woofer" failed in and because of that exact kit/enclosure/AMT; if manufacturer's FR doesn't lie, then Purifi itself is just gorgeous.

 

[Zvu]

Who would believe i would advocate for Purifi superiority

This is turning into a spitting contest and i'm out.

The measured data is at HiFicompass so anyone will decide for himself regarding price or performance.