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PURIFI finally did a fully purified passive speaker design! The SPK 16 prototype is here - with a PTT tweeter

kemmler3D said:
I'm interested to see where the breakup mode of this driver is. IIRC the Aluminum domes from Bliesma have theirs way up around 27khz or something, (at least I am sure they are ultrasonic) so much less problematic than others. Presumably Purifi has made some efforts in that regard. IMO that would remove some reason to seek out beryllium over aluminum.
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T25B vs A:
Bliesma comparison RefMic.jpg

Yes - 50kHz. They are the only ones who can push the resonance frequency that high.

ScanSpeaks:
FR SS664000 Compare.PNG

Reonance Frequency in the 35kHz area.

THD of the Bliesma is lower between 2-10kHz and rises above 10kHz compared to ScanSpeak Beryllium. It's one of the lowest THD tweeters I know, lower as T34 acording to HiFiCompass.
 
But the cheap (+/- 50€) SB acoustics SB26ADC is even better i think:
1716795935401.png

source: https://hificompass.com/en/speakers/measurements/sbacoustics/sb-acoustics-sb26adc-c000-4

The resonance is earlier, but very small in amplitude (what is more important i think), even off axis (what is not shown in the purifi graph). But i actually think distortion is a bigger issue than a resonance in the upper treble (that most don't hear anyway). And also there that cheap SB26ADC is very good:

1716796172493.png

Source: http://www.troelsgravesen.dk/SBA-tweeters.htm

I would expect that Purifi does better, and show full graphs. But at this moment i think they let us down on that. From what i've seen now it does not look that good in my opinion, and no match for their exellent woofers and midrange drivers.
 
IamJF said:
T25B vs A:
View attachment 371492
Yes - 50kHz. They are the only ones who can push the resonance frequency that high.

ScanSpeaks:
View attachment 371493
Reonance Frequency in the 35kHz area.

THD of the Bliesma is lower between 2-10kHz and rises above 10kHz compared to ScanSpeak Beryllium. It's one of the lowest THD tweeters I know, lower as T34 acording to HiFiCompass.
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BlieSMa aluminium dome breaks up at 30kHz though. Which is what the Purifi can be compared to given it's also aluminium.

Also SB acoustics beryllium tweeter seems to have much less of a resonant peak, breakup from 40kHz-50kHz
 
Waxx said:
But the cheap (+/- 50€) SB acoustics SB26ADC is even better i think:
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Hmmm, you can compare at HiFiCompass.
The diffusor seem to dampen the resonance on axis (which is relatively low at 25kHz) but look at 30° off axis. Compare of axis response - 60° above 10kHz. -12dB vs -6dB.
T25A is 2-4db louder.
THD ... don't even look at these linear graphs from Troels, totally useless. But we have good measurements from HiFiCompass. Both are very good, T25A a little better from 2,5kHz-10kHz. But both are top notch, doesn't get a lot better as these. Up to now ;-)

Interesting is that the measurements have totally different frequency responses >15kHz and both don't match the datasheet?

Price performance winner is clear. Wide radiation goes to T25A. Waveguide for low cost is the SB26ADC.

I only know the sound of the "original" ScanSpeak: https://www.scan-speak.dk/product/d2904-980000/
While it's one of the best ALU tweeters of that time it still has some of the metal tweeter "obtrusiveness" in my ears. I would rate the T25A higher and of course the T25B. But I never tried or compared the SB26ADC.
 
I know that the troels measurements are not detailed, but it's the only measurement i know outside the Hifi Compass, and at least on distortion they agree. I do trust the Hifi Compass measurements way more than the Troels altough..

The SB is the best tweeter I know, and yes i do know the Scanspeak D2904 and the Bliesma T25B, but the SB remains on top. Even in a blind test that a friend organised because he does not agree (to settle the argument, what failed). But i don't like the Berrillium tweeters in general (independent of brands), they sound forced detailed and to bright to my ears, even if the measurments don't show it. It's subtile, but it's there. The SB26ADC does not have the typical harddome sound, that the scanspeak still have, nor the forced details of the Berrillium tweeters. It almost sounds like a softdome, but with more detail.

But on this level, a lot becomes subjective. All mentioned are at least good tweeters. Even that Purifi looks quit decent. It's just that i'm a bit obsessed with good sound, and too bright resonant or forced sound does not fit into my plan.
 
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Waxx said:
I know that the troels measurements are not detailed, but it's the only measurement i know outside the Hifi Compass, and at least on distortion they agree. I do trust the Hifi Compass measurements way more than the Troels altough..

The SB is the best tweeter I know, and yes i do know the Scanspeak D2904 and the Bliesma T25B, but the SB remains on top. Even in a blind test that a friend organised because he does not agree (to settle the argument, what failed). But i don't like the Berrillium tweeters in general (independent of brands), they sound forced detailed and to bright to my ears, even if the measurments don't show it. It's subtile, but it's there. It does not have the typical harddome sound, that the scanspeak still have, nor the forced details of the Berrillium tweeters. It almost sounds like a softdome, but with more detail.

But on this level, a lot becomes subjective. All mentioned are at least good tweeters. Even that Purifi looks quit decent. It's just that i'm a bit obsessed with good sound, and too bright resonant or forced sound does not fit into my plan.
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Depends on the application I think.
I too can't stand "forced" detail and god-forbid bright speakers but I can listen for hours to Blumenhofer's beryllium drivers.
I guess it must be different at these 2" compression drivers though.
 
Waxx said:
I know that the troels measurements are not detailed, but it's the only measurement i know outside the Hifi Compass, and at least on distortion they agree. I do trust the Hifi Compass measurements way more than the Troels altough..

The SB is the best tweeter I know, and yes i do know the Scanspeak D2904 and the Bliesma T25B, but the SB remains on top. Even in a blind test that a friend organised because he does not agree (to settle the argument, what failed). But i don't like the Berrillium tweeters in general (independent of brands), they sound forced detailed and to bright to my ears, even if the measurments don't show it. It's subtile, but it's there. It does not have the typical harddome sound, that the scanspeak still have, nor the forced details of the Berrillium tweeters. It almost sounds like a softdome, but with more detail.

But on this level, a lot becomes subjective. All mentioned are at least good tweeters. Even that Purifi looks quit decent. It's just that i'm a bit obsessed with good sound, and too bright resonant or forced sound does not fit into my plan.
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Have you compared the SB aluminium with the SB beryllium? Given that they are more likely to be similar to each other than across brands
 
Penelinfi said:
Have you compared the SB aluminium with the SB beryllium? Given that they are more likely to be similar to each other than across brands
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Yes we did, i don't know what model exact anymore (because there are a few variations of the SB Beryllium), but that was where the discussion started. The Bliesma was thrown into the discussion later. The SB Berryllium is indeed close, but still sounds forced and too sharp bright. The Bliesma was not better, it was very similar than the SB Berrylium.
 
Waxx said:
The SB is the best tweeter I know, and yes i do know the Scanspeak D2904 and the Bliesma T25B, but the SB remains on top. Even in a blind test that a friend organised because he does not agree (to settle the argument, what failed). But i don't like the Berrillium tweeters in general (independent of brands), they sound forced detailed and to bright to my ears, even if the measurments don't show it. It's subtile, but it's there. The SB26ADC does not have the typical harddome sound, that the scanspeak still have, nor the forced details of the Berrillium tweeters. It almost sounds like a softdome, but with more detail.
Click to expand...

That's interesting - cause that's totally not my perception and the perception the few persons I know and trust who have listening experience and did comparisons with Beryllium tweeters!
For me it's the total opposite - Beryllium sounds very natural, the missing link between a soft dome and hard dome. Has all the details of a hard dome but doesn't push it in your face. I listened to the ScanSpeak Berylliums and the Bliesma T25B and found this behaviour very consistent.

Typical hard dome - they sound forced detailed and to bright to my ears, even if the measurments don't show it. ;)
T25A is a good one but still noticeable, the old Seas are pretty bad in my ears.

Seems I should try the SB26ADC one time ... but as the off axis performance is not what I search not sure if it finds it's way in one if my projects ...
Maybe when I do a budget waveguide speaker in the future.
 
Implementation rather than cone material, applying some pre-conceived subjective notion ‘ hard domes, forced and detailed’ is wrong.
Keith
 
Purité Audio said:
Implementation rather than cone material, applying some pre-conceived subjective notion ‘ hard domes, forced and detailed’ is wrong.
Keith
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Off course it is, but many did it wrong. SB and some others show that it's not the cone material on it's own, but how to use the cone material that makes the difference in sound. One of my favorite compression drivers (Faital HF-201) even use titanium cones (harder than aluminium) but also sounds very smooth, not hard at all.. It's all in the implementation largely. But cone materials do have a sound also, and Beryllium never sound natural to me. Maybe it's also the implementations i heared (Scanspeak, Bliema, SB and Radian are those i heared). But i know i should not judge only by cone material, i should listen and measure in the first place to jJudge it.
 
Waxx said:
I know that the troels measurements are not detailed, but it's the only measurement i know outside the Hifi Compass, and at least on distortion they agree. I do trust the Hifi Compass measurements way more than the Troels altough..

The SB is the best tweeter I know, and yes i do know the Scanspeak D2904 and the Bliesma T25B, but the SB remains on top. Even in a blind test that a friend organised because he does not agree (to settle the argument, what failed). But i don't like the Berrillium tweeters in general (independent of brands), they sound forced detailed and to bright to my ears, even if the measurments don't show it. It's subtile, but it's there. The SB26ADC does not have the typical harddome sound, that the scanspeak still have, nor the forced details of the Berrillium tweeters. It almost sounds like a softdome, but with more detail.

But on this level, a lot becomes subjective. All mentioned are at least good tweeters. Even that Purifi looks quit decent. It's just that i'm a bit obsessed with good sound, and too bright resonant or forced sound does not fit into my plan.
Click to expand...

One clear message from Krutke states on his driver distortion measurements is NOT to compare them to others. I treat Troels and others measures with that same regard. Of course, you have to trust the source to be sufficiently disciplined to make consistent measurement. Some like GR lack the discipline and claim that distortion measurements are not useful.

As for GR, did you see Danny’s recent hit job on the Troels 8008? Not reposting here but it is thinly disguised on the GR youtube site as “DIY Do’s and Dont’s.” Yes lol, he misspelled Don’ts. The main issue is poorly and incorrectly built cabinet but Danny clearly is digging on Troels too. Danny starts the video claiming about how he felt he needed to help poor DIYers avoid issues but is clearly more about how he feels about Troels.:facepalm:

p.s. LoL, may be a Danny “do” is to use spell check. His video title also Has Dos rather then Do’s!
 
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Rick Sykora said:
One clear message from Krutke states on his driver distortion measurements is NOT to compare them to others. I treat Troels and others measures with that same regard. Of course, you have to trust the source to be sufficiently disciplined to make consistent measurement. Some like GR lack the discipline and claim that distortion measurements are not useful.

As for GR, did you see Danny’s recent hit job on the Troels 8008? Not reposting here but it is thinly disguised on the GR youtube site as “DIY Do’s and Dont’s.” Yes lol, he misspelled Don’ts. The main issue is poorly and incorrectly built cabinet but Danny clearly is digging on Troels too. Danny starts the video claiming about how he felt he needed to help poor DIYers avoid issues but is clearly more about how he feels about Troels.:facepalm:
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...should add that Danny's own measurements show a better high end rolloff than Troels (despite having measured on the wrong axis). While he does claim to match the 8008's curve, he misses in the top octave. As he applies both gating and smoothing (and then 25 dB scaling), likely he is once again applying mods that do not address true issues....

Here is a look and you can see how his added smoothing (green trace) is different than Troels. Ignore below 200 Hz as his gating is affecting. As he makes crossover mods. he zooms in to double the scaling and so exaggerates his smoothed curve. :oops:

1717170519531.png


Also find it ironic that he initially claims the waterfall is pretty clean, but later discovers the lack of bracing and breaks out an accelerometer to show how bad the build was. Seems more likely to confuse rather than clarify how to test and fix cabinet resonances. Am sticking to my premise that these are GR promo videos but, in this case, to deride a competitor (who barely charges for his designs) versus Danny who upsells of magical caps, wires and connectors for his stuff.
 
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I guess waiting for the tweeter, integral part of the design. There has been a heavy lobbying for the design to be released to the public, hope it materialises soon.
 
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Lbstyling said:
Great!

Am currently running KEF R3 meta.

Until Purifi make an 80 degree wide pattern coax, the SPK16 is the only thing that takes my interest.
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You can always make your own coax with the tweeter of your choice..
 
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