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Celuaris SPK5 Purifi Review (speaker)

MZKM

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Mainly because the estimated in-room response is smoother and more tilted than that of the 708P.
Correct. An idiosyncrasy of the score is it prefers narrow directivity. You can see for the JBL that the SM_PIR score is lower while this one is higher.

However, it’s not just the wideness of the dispersion; looking at the PIR for the JBL, it is not linear. You can draw a downward sloping line from 100Hz-1500Hz, but above that you would need to draw an upward sloping line:
EE0B5BE0-261D-453A-9981-FF0BAB3BD63C.jpeg
 
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Massimo

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

The SPK4 was built with by Purifi (with care) to their exact spec. The SPK5 was slapped together by an inexperienced builder and not to spec. There are many issues, like crossover and damping, which are not as per Purifi's spec.
 

Grandzoltar

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Maybe in a MTM design transmission cabinet with a dome tweeter would net better results. Maybe DMurphey could tweak the crossover design.
 

test1223

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I don't know why people are bothering with planars going that low. Domes do much better job, especially waveguide loaded.
The benefit of planar tweeter is the more narrow vertical beam and some designs provide the lowest possible inter modulation distortion and high max spl. Some of the mundorf amts are very good.

Problems of the design
There are two main problems why this design didn't sound good. First the frequency response at the listening window don't compensate the not optimal DI. From 3kHz to 7kHz there is to much power, from 400Hz to 1kHz there is also to much power. The other major issue is the bass tilt form 100Hz down to 30Hz. This sort of chassie would also benefit a lot from a subsonic filter.
Some minor improvement would be a rise slight rise of the 0° frequency response from 12kHz to 20kHz and the Bass reflex port issue.
With some equalization it should sound a lot better, but there might be some other issues which can't be observed by the provides measurement like the lack of well placed damping material and such stuff.
 

MediumRare

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Great example of the scoring not making any sense whatsoever. @amirm , is this not the straw that breaks the camel’s back? We need a better score that relates to subjective, empirical, listening experience.
 

Rick Sykora

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Thanks @amirm!

Your measurements and listening correlate well with mine. Having helped get this SPK5 to spec, have to agree that the design could be better. Most notable of which could be addressed with some bass boost. Not sure which listening material might cause the woofer to hit its excursion limits as I did not experience (in my sizable family room).

Those questioning the build should note that the impedance curve is spot on with the Purifi specs. This says the bass tuning is according to design. While I agree you should be able to extract more bass from this woofer, am confident it is what the designer intended. Am still working on a mod that with a couple of different passive radiators. For those who may be interested, see this thread.

Finally, after I updated the build, had a chance to listen to a pair of SPK5s. The clarity is good, but the highs are a bit much for my taste. The imaging seemed very precise, but I did not critically evaluate. The bass (albeit boosted) had good authority with my Hypex NC252MP driving them. With a rear-facing port, did not hear any obvious signs of the 400 Hz port resonance, but the speakers were also mounted far in front of the back wall. While I do not like the optics, if I got rid of every speaker I have with port resonance, I would not have as many as I do. :D
 
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JohnBooty

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That's a lotta bucks for those speakers. USD $2700.00 could buy some pretty nice factory made speakers but I guess that defeats the DIY MODDER mentality.
I don't disagree with the first part of this sentence but the second part seems... like a weird potshot to take.
 

617

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I agree that sealed dsp boosted use is probably most logical for this woofer. Scanspeak/wavecor/seas have kind of perfected the passive midwoofer, this is in some ways a step forward and a step back.

I look forward to seeing measurements of the waveguide model if someone sends it in, but I think the lesson here is that this woofer is very hard to design with.
 

ROOSKIE

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Correct. An idiosyncrasy of the score is it prefers narrow directivity. You can see for the JBL that the SM_PIR score is lower while this one is higher.

However, it’s not just the wideness of the dispersion; looking at the PIR for the JBL, it is not linear. You can draw a downward sloping line from 100Hz-1500Hz, but above that you would need to draw an upward sloping line:
Great example of the scoring not making any sense whatsoever. @amirm , is this not the straw that breaks the camel’s back? We need a better score that relates to subjective, empirical, listening experience.

The JBL 708P has a very robust DSP engine built in.
It has a myriad of presets and customizable features. Quite robust. One could likely adjust the speaker in such a way as to greatly increase the Harman score, or more meaningfully to match ones tastes/needs/room.
I am actually not sure what setting the 708P test was conducted under.
In any case it seems that the Harman score is what it is - an indicator. A probability, a likelihood - not a fact.
Now most everyone knows this and knows that data is older now and somewhat limited in scope compared with ideals, it can be improved. That requires a mess load of people to participate in a new, bigger, better more comprehensive study. Even then there will still be times where the score simply doesn't match.


This Purifi woofer really is polarizing receiving compliments and severe criticism & IMHO it should. It is really a very niche product that is practically equal/inferior to much less expensive and much less flashy design in many ways, it does however have some very nice attributes that if are properly contemplated, could position this woofer in a nice design that makes sense for certain purposes. The ultimate cost of the RAW drivers is problematic as IMHO they just are not competitive, if they gain a market share and can drop the price I can certainly see the tech having value.
Spatial characteristics are not bad. Surprised the bass didn't wow more but who knows, maybe there's only so much you can do with a small woofer.
Yah, I mean that incredible Xmax is easily outdone if you can use a larger system. I guess the whole point of the Purifi to allow one to stay small.

Just sort of apples to big apples size wise but really similar in terms of "DIY" vibes and what you can get for a price,
Look at what the cash buys.
This uses a passive radiator, a truly world class 9.5" woofer with a fantastic world class waveguide loaded beryllium tweeter.

Yah you have to put it together but what is shown below is a retail kit price for a pair with passive crossover parts- the RAW driver cost is in the same ball park as a RAW Purifi with Passive Radiator and that iffy tweeter.

You can do the Helios kit or in my case you can buy the raw drivers and DIY an active design.

Anyway I am not salesman for anyone, just a interesting example. This DIY speaker uses 1 cubic foot of volume so not huge. No way I buy a Purifi system for the same price as what I'd get in this example kit.

1612631667928.png

1612631811813.png
 

YSC

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The JBL 708P has a very robust DSP engine built in.
It has a myriad of presets and customizable features. Quite robust. One could likely adjust the speaker in such a way as to greatly increase the Harman score, or more meaningfully to match ones tastes/needs/room.
I am actually not sure what setting the 708P test was conducted under.
In any case it seems that the Harman score is what it is - an indicator. A probability, a likelihood - not a fact.
Now most everyone knows this and knows that data is older now and somewhat limited in scope compared with ideals, it can be improved. That requires a mess load of people to participate in a new, bigger, better more comprehensive study. Even then there will still be times where the score simply doesn't match.


This Purifi woofer really is polarizing receiving compliments and severe criticism & IMHO it should. It is really a very niche product that is practically equal/inferior to much less expensive and much less flashy design in many ways, it does however have some very nice attributes that if are properly contemplated, could position this woofer in a nice design that makes sense for certain purposes. The ultimate cost of the RAW drivers is problematic as IMHO they just are not competitive, if they gain a market share and can drop the price I can certainly see the tech having value.

Yah, I mean that incredible Xmax is easily outdone if you can use a larger system. I guess the whole point of the Purifi to allow one to stay small.

Just sort of apples to big apples size wise but really similar in terms of "DIY" vibes and what you can get for a price,
Look at what the cash buys.
This uses a passive radiator, a truly world class 9.5" woofer with a fantastic world class waveguide loaded beryllium tweeter.

Yah you have to put it together but what is shown below is a retail kit price for a pair with passive crossover parts- the RAW driver cost is in the same ball park as a RAW Purifi with Passive Radiator and that iffy tweeter.

You can do the Helios kit or in my case you can buy the raw drivers and DIY an active design.

Anyway I am not salesman for anyone, just a interesting example. This DIY speaker uses 1 cubic foot of volume so not huge. No way I buy a Purifi system for the same price as what I'd get in this example kit.

View attachment 110898
View attachment 110899
This kit looks surprisingly good for me
 

Newman

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1612640079148.png


“Something happening around 350 Hz....”

1612640143415.png


“Port resonance at 350 Hz....”

1612640210700.png


...and I see the smoothly increasing beam width as we drop below 1 kHz suddenly beams again at..... 400 Hz!


1612640246978.png


And this graph shows that beaming as being closer to .... 350 Hz again.

Can a port resonance cause a speaker to ‘beam’? With an output 6-8 dB below the woofer? Or is there something else going on directly from the Purifi woofer that causes this?

cheers
 
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Newman

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The speaker’s listed attributes says the crossover is 3.2 kHz, but the measurements look more like 2.1 kHz. Isn’t that a bit weird?

1612640675097.png
 

test1223

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Can a port resonance cause a speaker to ‘beam’? With an output 6-8 dB below the woofer? Or is there something else going on directly from the Purifi woofer that causes this?
The artifacts at 350Hz are caused by the port and it doesn't beam more. It beams less you can see it in the DI.

The speaker’s listed attributes says the crossover is 3.2 kHz, but the measurements look more like 2.1 kHz. Isn’t that a bit weird?
No it is about 3,5kHz you can see it at the woofer slope and at the change in the DI.
 

ctrl

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The speaker’s listed attributes says the crossover is 3.2 kHz, but the measurements look more like 2.1 kHz. Isn’t that a bit weird?
You cannot equate near-field measurements of the chassis with far-field measurements. For example, the influence of the baffle is missing in the near-field measurements. In Amir's near-field measurements, all drivers radiate sound, so there is additional interference.


You can do the Helios kit or in my case you can buy the raw drivers and DIY an active design.
This kit looks surprisingly good for me

However, those who value optimal directivity should wait until angular frequency response measurements are available for the kit before buying.

Due to the fact that the crossover frequency is at 1.3 kHz, there should still be significant influences of edge diffraction on the tweeter despite the waveguide.
 

Newman

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The artifacts at 350Hz are caused by the port and it doesn't beam more. It beams less you can see it in the DI.

Check again.
1612643589801.png


As the frequency drops below 1 kHz the beam width broadens out to 200 degrees then suddenly it beams again to under 100 degrees at 400 Hz.
 
OP
amirm

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Can a port resonance cause a speaker to ‘beam’?
Since the port resonance is out of phase with the woofer, it is causing cancellations in different places around the speaker. It is not beaming per-se.
 

McFly

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The port resonance can act as a cancelation to the rear wave as it is rear ported, thus causing a cardioid high Q effect at that frequency
 

test1223

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Check again.
View attachment 110921

As the frequency drops below 1 kHz the beam width broadens out to 200 degrees then suddenly it beams again to under 100 degrees at 400 Hz.
If you imagine one sphere around the speaker the figure you shown represents only a line on the sphere. So yes you get some dips and peaks due to the phase difference between woofer and port. At this line there is a dip. But over the whole sphere the speaker radiates more energy into the room, as you can see in the DI.
 

Doodski

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I don't disagree with the first part of this sentence but the second part seems... like a weird potshot to take.
Not a pot shot at all. I meant it. The MODDERS and DIY crowd like to build themselves and they enjoy that and buy tools and all sorts of stuff for the tasks. I've been a DIY MODDER in the past and it's fun. :D
 
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