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The Sointuva (Finnish for musical harmony) is based on the Purifi Ptt6.5W04 woofer, PTT6.5 PR passive radiators and the Bliesma T34B-4 Beryllium tweeter.
March Audio Sointuva Speaker | Audio Science Review (ASR) Forum
The Sointuva (Finnish for musical harmony) is based on the Purifi Ptt6.5W04 woofer, PTT6.5 PR passive radiators and the Bliesma T34B-4 Beryllium tweeter.
March Audio Sointuva Speaker | Audio Science Review (ASR) Forum
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A couple of new technical posts on Purifi speaker technology from A list sources.
HiFi Compass reviews PTT4.0W04-01A 4” class woofer.
Purifi Audio PTT4.0W04-01A midwoofer | HiFiCompass
Summary from HiFi Compass
Testing confirmed a very close correspondence of all the measured parameters to the declared ones.
The measured characteristics let to classify the PTT4.0W04-01A as a 4" midwoofer of the highest class. In fact, today it is the world's best midwoofer in its class. If the concept of "Big sound out a small box" is close for you, then there is simply no better option to find. Bravo, PURIFI!
SoundStage!Hi-Fi measures the SPK5 application note demo speaker with PTT6.5W04 in the anechoic chamber of Canada’s National Research Council.
SoundStage! Hi-Fi | SoundStageHiFi.com - The Purifi Puzzle, Part Two: The Measured Performance of the SPK5 Loudspeaker
Quotes from SoundStage!Hi-Fi
Takeaway: Within the PTT6.5W04’s operating bandwidth, its performance remained excellent even under these brutal test conditions. No other speaker with a single, similarly sized midrange-woofer has exhibited such low distortion at so high an output level and remained that linear. As Purifi promised, their PTT6.5W04 driver can achieve excellent linearity and low distortion even at high output levels.
HiFi Compass reviews PTT4.0W04-01A 4” class woofer.
Purifi Audio PTT4.0W04-01A midwoofer | HiFiCompass
Summary from HiFi Compass
Testing confirmed a very close correspondence of all the measured parameters to the declared ones.
The measured characteristics let to classify the PTT4.0W04-01A as a 4" midwoofer of the highest class. In fact, today it is the world's best midwoofer in its class. If the concept of "Big sound out a small box" is close for you, then there is simply no better option to find. Bravo, PURIFI!
SoundStage!Hi-Fi measures the SPK5 application note demo speaker with PTT6.5W04 in the anechoic chamber of Canada’s National Research Council.
SoundStage! Hi-Fi | SoundStageHiFi.com - The Purifi Puzzle, Part Two: The Measured Performance of the SPK5 Loudspeaker
Quotes from SoundStage!Hi-Fi
Takeaway: Within the PTT6.5W04’s operating bandwidth, its performance remained excellent even under these brutal test conditions. No other speaker with a single, similarly sized midrange-woofer has exhibited such low distortion at so high an output level and remained that linear. As Purifi promised, their PTT6.5W04 driver can achieve excellent linearity and low distortion even at high output levels.
I'm back, lots of life things have kept me away from speakers in the last 6ish months. Still loving these speakers. New house and garage and I'm keen to get back into it. Big lounge and I need to get rid of the stand mounts. No need anything below 30Hz but would like a couple more dB.
What are peoples thoughts on how to enclose the Purifi 6.5 while offloading the low bass to some woofers at 100-150hz, in a floorstander? Would one just seal it with heavy fill small dedicated enclosure, or build it into its own 15L reflex enclosure at the top of the cabinet?
I have some dayton 8" woofers here from past builds I could parallel up to take the deep lows or go 12/15" sealed woofers, as mentioned by others at the beginning of this thread. Brainstorming. Remember I'm using DSP crossovers.
What are peoples thoughts on how to enclose the Purifi 6.5 while offloading the low bass to some woofers at 100-150hz, in a floorstander? Would one just seal it with heavy fill small dedicated enclosure, or build it into its own 15L reflex enclosure at the top of the cabinet?
I have some dayton 8" woofers here from past builds I could parallel up to take the deep lows or go 12/15" sealed woofers, as mentioned by others at the beginning of this thread. Brainstorming. Remember I'm using DSP crossovers.
Hi mainframe99,
My direct experience using subwoofers with PTT6.5Ws thus far is with 4 x 10” in sealed push-pull enclosures (a pair on the left the other pair for the right in stereo) bi-amped. The Purifi in my Fi16v1 allowed to run without low cut crossover to the sub and subs low pass filtered to blend in below 90 Hz. It was great fun after all more bass power is always fun especially at first during the honeymoon phase. These subs are in undersized boxes so they are over damped and thus not prone to booming. That setup did not get to the subwoofer post-honeymoon stage when one tries to dial it into the Nth degree after becoming aware of the warts. The electronic crossover was re-purposed back to allowing the PTT6.5Ws and ribbon tweeters to be bi-amped thus the subs falling silent.
Speculating about “thoughts on how to enclose the Purifi 6.5 while offloading the low bass to some woofers at 100-150hz, in a floorstander?” My first thought was PTT6.5W is designed for vented, I’m enjoying great success in vented (actually passive radiators) so why go sealed. Firing up WinISD there was a route that appeared I find interesting. The screen captures I attach illustrate this. These show sims of one PTT6.5W in first maximally flat vented and then two sealed boxes with the common choices of Qs set to 0.5 and 0.707. The Group Delay shows the typical swing at tuning frequency vented boxes show and the flatter delay that characterizes sealed boxes. Recall there are varying opinions on the audibility of the vented boxes’ low frequency phase shifts. With Group Delay out of the way onto the frequency response sims.
The green trace shows a vented 0.5 cu ft box tuned to 37 Hz, approximately the SPK5 Purifi application note design. The orange and blue traces are the sealed box sims for the common 0.5 and 0.7 Q sealed alignments. First one sees for a 2-way this is certainly a vented box speaker. Nobody wants to pay $250-$300 for a 6” woofer that’s down 3 dB at 90-100 Hz. HOWEVER in mainframe99’s and others who want to explore 3-ways or 4-ways –3 dB at 90 Hz is just part of the crossover. Personally I am so enamored (fanboy – yes) with Purifi bass I am loath to give up my Purifi bass 30-100 Hz.
And then I noticed something interesting. The vented box is 0.5 cu ft (15L) and the Qtc 0.5 sealed box is 0.48 cu ft. (13.8L). BINGO there’s my path if I ever get around to a 3-way with PTT6.5W (not likely watch this space for what I have been busy with). It is not that uncommon to see midranges in vented enclosures these days, perhaps others have thread this path with other drivers before us. So my suggestion is a 3-way with PTT6.5W in a 0.5 cu ft (15L) sub-enclosure vented out the back with some means to seal off that port. Something like a plate with gasket and four screws to really seal off that port (see https://www.diyaudio.com/forums/multi-way/352063-exploring-purifi-woofer-speaker-builds-48.html#post6383932). Now once the prototype is running in the listening room one can experiment actually with three configurations. First PTT6.5W vented midrange. Second PTT6.5W as sealed midrange. Third with loosely stuffed port PTT6.5W as aperiodic (lossy sealed) loaded midrange.
Happy Listening (and designing)
My direct experience using subwoofers with PTT6.5Ws thus far is with 4 x 10” in sealed push-pull enclosures (a pair on the left the other pair for the right in stereo) bi-amped. The Purifi in my Fi16v1 allowed to run without low cut crossover to the sub and subs low pass filtered to blend in below 90 Hz. It was great fun after all more bass power is always fun especially at first during the honeymoon phase. These subs are in undersized boxes so they are over damped and thus not prone to booming. That setup did not get to the subwoofer post-honeymoon stage when one tries to dial it into the Nth degree after becoming aware of the warts. The electronic crossover was re-purposed back to allowing the PTT6.5Ws and ribbon tweeters to be bi-amped thus the subs falling silent.
Speculating about “thoughts on how to enclose the Purifi 6.5 while offloading the low bass to some woofers at 100-150hz, in a floorstander?” My first thought was PTT6.5W is designed for vented, I’m enjoying great success in vented (actually passive radiators) so why go sealed. Firing up WinISD there was a route that appeared I find interesting. The screen captures I attach illustrate this. These show sims of one PTT6.5W in first maximally flat vented and then two sealed boxes with the common choices of Qs set to 0.5 and 0.707. The Group Delay shows the typical swing at tuning frequency vented boxes show and the flatter delay that characterizes sealed boxes. Recall there are varying opinions on the audibility of the vented boxes’ low frequency phase shifts. With Group Delay out of the way onto the frequency response sims.
The green trace shows a vented 0.5 cu ft box tuned to 37 Hz, approximately the SPK5 Purifi application note design. The orange and blue traces are the sealed box sims for the common 0.5 and 0.7 Q sealed alignments. First one sees for a 2-way this is certainly a vented box speaker. Nobody wants to pay $250-$300 for a 6” woofer that’s down 3 dB at 90-100 Hz. HOWEVER in mainframe99’s and others who want to explore 3-ways or 4-ways –3 dB at 90 Hz is just part of the crossover. Personally I am so enamored (fanboy – yes) with Purifi bass I am loath to give up my Purifi bass 30-100 Hz.
And then I noticed something interesting. The vented box is 0.5 cu ft (15L) and the Qtc 0.5 sealed box is 0.48 cu ft. (13.8L). BINGO there’s my path if I ever get around to a 3-way with PTT6.5W (not likely watch this space for what I have been busy with). It is not that uncommon to see midranges in vented enclosures these days, perhaps others have thread this path with other drivers before us. So my suggestion is a 3-way with PTT6.5W in a 0.5 cu ft (15L) sub-enclosure vented out the back with some means to seal off that port. Something like a plate with gasket and four screws to really seal off that port (see https://www.diyaudio.com/forums/multi-way/352063-exploring-purifi-woofer-speaker-builds-48.html#post6383932). Now once the prototype is running in the listening room one can experiment actually with three configurations. First PTT6.5W vented midrange. Second PTT6.5W as sealed midrange. Third with loosely stuffed port PTT6.5W as aperiodic (lossy sealed) loaded midrange.
Happy Listening (and designing)
Attachments
Thanks for your time Norman, I think you nailed it. I will do that. There’s even a tool we use for sealing ports.
Duct Sealing Plugs - Duct Seals - Cable Glands & Duct Seals - TransNet NZ Ltd
Duct Sealing Plugs - Duct Seals - Cable Glands & Duct Seals - TransNet NZ Ltd
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Purifi SPK5 Speaker Review (Prototype)
Not looking good.
Purifi SPK5 Speaker Review (Prototype) | Audio Science Review (ASR) Forum
Not looking good.
Purifi SPK5 Speaker Review (Prototype) | Audio Science Review (ASR) Forum
I think we all knew that was coming with the AMTs wobbly response, the crossover so high, the woofer beaming, the cabinet leaves a lot to be desired, and the port. I had comparable results back when I was experimenting with the AMT. They have been shelved for the meantime, perhaps a future project. I had significant port noise and resonance and the AMT wiggles. I didn’t have the poor seal issues, didn’t get far enough to check impedance. Much better results with an SB26ADC and some SB Racetrack PRs.
I'm wondering how much of an improvement (if any) the Purifi PRs are compared to the SB racetracks, or other reasonably good PRs for that matter. The cost increase is quite hard for me to justify, unless going with inexpensive PRs significantly subtracts from the performance of the PTT6.5s. Thoughts on this?
The major problem I see with the ASR review is the reviewer fell into a sunken cost trap. Review unit arrived with significant shipping damage. Reviewer admits he tried repairs with questionable results. Reviewer complains “very hard for me to figure out what went where” as he attempts repair of crossover. He is doing this apparently unaware of the SPK5 app note until after publishing, see post 15 & 17 in review discussion. I also have a question on the providence of the ASR sample. Unlike the unit measured in the National Research Council of Canada facility which was built by Purifi the ASR unit was built by somebody that goes by ‘Celuaris’ and is selling the SPK5 evaluation design based speakers on UK eBay for GBP 1,999.00. So what variances are due to production ‘engineering’ issues with Celuaris’ realization of the SPK5 design vs. the shipping damage and resulting ASR repair attempt is unknowable. What is knowable is comparing the impedance plots ASR published vs SoundStage!Hi-Fi’s.
ASR
SoundStage!Hi-Fi
The biggest fault I find with amirm’s ASR review is that he went forward seeing that impedance plot. Even without comparison to the one made at NRC what I see is a broken speaker. A common newb mistake made by Celuaris entering the speaker business underestimating how overbuilt shipping boxes/padding must be in 2020. I characterize this as a case of sunken cost fallacy because after investing his time attempting the repair amirm proceeded with his review holding off the telling Z-plot until he had his content specifically graph after graph of acoustic measurements. Alas all made on a seriously wounded unit. I am guessing wanting the review of a Purifi woofer based system on ASR he proceeded rather than contact Celuaris with the sad news the review samples after the UK to USA West coast journey are a write off.
That’s the same conclusion that I had, the driver is badly damaged. Probably the voice coil or suspension is out of alignment. That impedance peak (split with anomaly) near 55Hz looks nasty and a DATS sweep on the bare driver would probably have been more instructive than proceeding with the whole review. A PTT6.5 should not be making 3.5% THD at 86dB. That’s crazy way off from specs or other people’s measurements. It’s like C&D receiving a McLaren after delivery from UK that looks like it was in a wreck and proceeding with the car evaluation after asking their local mechanic to fix it without a manual and then proceeding to test it and write the report.
In my PTT6.5 TL, I measured -50dB THD at 2.0Vrms and 0.5m. You can probably extrapolate that to -44dB at 2.83v and 1m as the driver is operating well below its Xmax. That’s about 0.6% THD. Although a TL is in general, able to get bass with lower distortion than a bass reflex box.
Finally, a big tell tale that something is very wrong was this statement: “ There was a big miss though and that was any kind of physical bass response. Even at much elevated levels, you could barely feel the bass.” Complete antithesis of what the PTT6.5 seems to provide for all other reviewers. Real bass that kicks hard.
In my PTT6.5 TL, I measured -50dB THD at 2.0Vrms and 0.5m. You can probably extrapolate that to -44dB at 2.83v and 1m as the driver is operating well below its Xmax. That’s about 0.6% THD. Although a TL is in general, able to get bass with lower distortion than a bass reflex box.
Finally, a big tell tale that something is very wrong was this statement: “ There was a big miss though and that was any kind of physical bass response. Even at much elevated levels, you could barely feel the bass.” Complete antithesis of what the PTT6.5 seems to provide for all other reviewers. Real bass that kicks hard.
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I am test running a Purifi 6.5 in one small PA speaker cabinet against the original 18 Sound 8MB500 in another.
1kw is available to each woofer/ ribbon combination.
The Purifi has a high excursion but exhibits no difficulty keeping up with the 18 Sound driver.
The main difference being the Purifi makes the ribbon sound sooo much cleaner, while the 18 Sound muddles the beautiful clarity of the Pro-Ribbon.
I am using Master Audio only for testing.
Can you "feel" the Purifi well not really, its punch seems to drop off at about 4m.
But then would I expect it not too in a small club room 200Sqm x 6.5m ceiling.
Typical SPL in the room is around 102db.
Could a line array of Purifi's generate a chest slamming SPL level? - I don't know at this stage.
1kw is available to each woofer/ ribbon combination.
The Purifi has a high excursion but exhibits no difficulty keeping up with the 18 Sound driver.
The main difference being the Purifi makes the ribbon sound sooo much cleaner, while the 18 Sound muddles the beautiful clarity of the Pro-Ribbon.
I am using Master Audio only for testing.
Can you "feel" the Purifi well not really, its punch seems to drop off at about 4m.
But then would I expect it not too in a small club room 200Sqm x 6.5m ceiling.
Typical SPL in the room is around 102db.
Could a line array of Purifi's generate a chest slamming SPL level? - I don't know at this stage.
Yess! I've been at ASR for some time too, and I'm not happy at all with the quality of Amir's tests. He is too busy and skips QC of his own work. He too much trust his fancy and expensive Klippel NFS and forgets some very basic things. I hate spelling mistakes too. These issues lead to annoying debates in threads when some knowleable people try to help him and do question his findings and conclusions. But it's a nice webpage to have around anyway!