This PTT6.5W04-01A is a fantastic driver. A new reference ! Very expensive but so much more worth it compared to other similarly priced "high end" drivers. Actually, I bet some high end speakers manufacturers will dismiss it because of its surround appearance despite its extraordinary capabilities 
And your new IMD measurements are an excellent addition to your website !
And your new IMD measurements are an excellent addition to your website !
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Not really much better than say a MW16p. The surround induced midband k2 spike is non-exist, but the audibility of it is questionable.
Yes the bass output SPL can be higher, but how about a separate sub to make 3-way compared to a 2-way box with not so good looking surround? Plus the freedom in placement for room integration.
Its IMD performance at 10mm is as good or better than the next best driver at 3mm excursion.
This is exceptional performance. It is second to none if a small 2-way is all you can fit in your decor and you're looking for the most clean volume available for that class.
There are better value propositions if you can go up in size. This has always been the case.
This is exceptional performance. It is second to none if a small 2-way is all you can fit in your decor and you're looking for the most clean volume available for that class.
There are better value propositions if you can go up in size. This has always been the case.
When comparing the 20mm HD measurements, the Purifi has 20dB to 30dB less H2 from 60hz to 200hz compared to the MW16. And in the IMD department, it still measures better than the MW16 with twice the excursion. So even with a sub with a 70hz to 90hz crossover, the Purifi is going to be a better driver. And the Satori is very good in the first place, which makes the Purifi all the more impressive.
As far as the surround is concerned, form follows function. Its weird appearance is partly responsable for the IMD performance. For a lot a people, drivers in general are ugly anyway.
Its only downside is its price, really. I would still take it over the new Seas "graphene" drivers, or the even more expensive Scanspeak Elipticor or Accutons.
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Technically for sure it should be better at 3 times the price than a satori. H2 and IMD, yes definitely lower on paper. I put satori as an example because some other manufacturers are betting a lot on brand names, or very much on looks, and no doubt these still sell in the aimed market.
Who would be the target customers for Purify? Definitely not rich people who can not read these plots.
For hardcore diyers maybe, but I prefer take off the load by bass management. Then the midband IMD is not so affected. Higher k2 needs to modulate with high excursion to produce high IMD, also helped by management. On the 2nd HD itself, what evidence is out there that 10db lower means audible improvement?
Who would be the target customers for Purify? Definitely not rich people who can not read these plots.
For hardcore diyers maybe, but I prefer take off the load by bass management. Then the midband IMD is not so affected. Higher k2 needs to modulate with high excursion to produce high IMD, also helped by management. On the 2nd HD itself, what evidence is out there that 10db lower means audible improvement?
Someone needs to prove that -80dB in regard to -60dB of any type of distortion is perceivable at all. Then we can talk about if this is actual progress.
First Lars says that larger mass is there because of the voice coil and that the cone is actually lighter than its aluminium and pp counterparts but then he talks about how higher cone mass allows higher stiffness and by that higher bandwidth. I agree buddy but you've just said that you didn't get to higher Mms that way.
Then quite cheesy comment about stronger motor in Bugatti Chiron and how it is heavy but fast. I'm not worried about how will it move, but how will it stop with twice as large mass and inertia of regular 7" driver and Cms of 1.1mm/N.
Price is just insane. For 900 euros (price of one pair of these woofers) one can buy drivers for a pair of high end standmount three ways - smooth power response, low distortion and higher spl capability than what ever could be achieved with this midwoofer.
I do like frequency response, on and off axis. Impedance is great also. It looks like it would be simple to work with.
First Lars says that larger mass is there because of the voice coil and that the cone is actually lighter than its aluminium and pp counterparts but then he talks about how higher cone mass allows higher stiffness and by that higher bandwidth. I agree buddy but you've just said that you didn't get to higher Mms that way.
Then quite cheesy comment about stronger motor in Bugatti Chiron and how it is heavy but fast. I'm not worried about how will it move, but how will it stop with twice as large mass and inertia of regular 7" driver and Cms of 1.1mm/N.
Price is just insane. For 900 euros (price of one pair of these woofers) one can buy drivers for a pair of high end standmount three ways - smooth power response, low distortion and higher spl capability than what ever could be achieved with this midwoofer.
I do like frequency response, on and off axis. Impedance is great also. It looks like it would be simple to work with.
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I agree we don't have to dig down into -80dB, which is likely buried beneath the noise floor of the room.
But I feel you may have not had a chance to take a deep dive into the graphs.
Do you have access to the Login/3 driver comparison feature?
Have a closer look again at how it compares to bigger bass drivers.
For brevity- I have attached 2 images below, cropped from Hificompass.com for educational purposes.
Both drive units are driven @ 5.6V, cropped at 300Hz to show what this novel 6.5 unit can do, compared to a 9" woofer.
Yes, your eyes are not deceiving you- the PTT6.5W04-01A is the left, the NINE INCH Satori WO24P-4 is the right...
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That settles the price point. Local group buys?
As for power handling, 100 watts noise for 100 hours into 4 ohms nominal rating, 350 watts for 1 minute.
A narrow 2H peak around 2.5kHz also appears in the new datasheet, but it will be attenuated by crossover filtering if it even mattered in the first place.
As a point of comparison, it doesn't seem to be cleaner than SB17NAC/NBAC/CAC in the midrange and up. The SB metal cones and the Purifi have an easily worked response, but the Purifi has far more linear stroke than any of the 6-7 inch SB drivers. Beams slightly higher up than NBAC even though Sd is slightly greater.
In terms of LF HD spectra, it seems to come in just below the 23NAC as measured. Needs two-tone tests to probe Bl(x), Kms(x), and Le(x, f) of the SB.
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I have compared it actually. I'm in agreement that it has lower distortion than lots of other woofers and midwoofers. Thing is, i don't consider distortion under 100Hz has any correlation to perceived bass quality anywhere else but in an anechoic chamber - though it has just 2nd harmonic lower, not 3rd. Also, what are SPL's of those woofers at that voltage? Distortion in rest of the spectrum is stellar but is the difference between a driver that has 3rd at -70dB and the one that has it at -90dB perceivable at all ? Which parts of percent are we talking about - 0.03% vs 0.003% ? That is measurable progress but not where is needed the most in my opinion.
Let's expand a little bit. This is a loudspeaker that has low distortion, no question about that. Then it remains low distortion at higher SPL (100dB). I'd argue that for midwoofer of that size it isn't necessary. If you are making Purifi PTT play at 100dB spl, since you have two, that gives 106dB at 1m total for two loudspeakers. That means to me that you either have a large room or you are deaf. If you are deaf, then it might be justified. If you have a large room, it negates the main advantage of this loudspeaker of being small and needs a small cabinet since you obviously have room and can accommodate larger cabinets with higher SPL output potential.
I'll just quote myself from other forum:
It models reasonably well in volume of 15 liters and tuned to 35Hz.
https://i.postimg.cc/KzWH0hMs/image.gif
Port resonance problem can be seen and while it looks severe, it can be absorbed or mitigated to some extent by placing the vent on the back side. Other problem is port noise and at 18W when port diameter is 50mm and length is 26.7cm with two flares it looks like this.
https://i.postimg.cc/k4wSxW2n/image.gif
For loudspeakers that i want clean bass from i keep port air speed bellow 14ms. Lets say that at 17m/s it becomes audible, and that you really don't want to go above 26m/s then maximum power you can let through these woofers is 39Watts. All this happens at 60% of Xmax, over that and chuffing becomes serious distortion source so the point of low distortion woofer with 10mm Xmax is lost.
If we make the port larger, let's say 68mm, to minimize port air speed, port resonance goes down to around 320Hz and good luck mitigating that.
https://i.postimg.cc/8zRLp7hm/68.gif
Again, the port induced distortion is too large to be neglected in my opinion.
I'd say that passive radiators should be used with these woofers or closed cabinets with appropriate low frequency boost. Then there are some advantages of low distortion that can be put to good use. But it would have to be quite a boost to get these results in closed cabinets (6-8dB boost at 40Hz actually). Distortion levels rise as well.
Thing that really puts me off for two way is 30 grams Mms, more than double from Revelator, Satori, Seas Nextel, Excel and Prestige woofers. Although Cms is 1.3 i am doubtful how would it sound. I guess that we'll just have to wait and see.
I'd always buy two Satori MW16P-8, instead of one Purifi woofer, and made an MTM with elliptic waveguide. 260€/pair vs 450€/piece - i think value is on my side and it just might be that performance would be too - less power compression, no port distortion at higher volume, lower combined Mms of both Satoris than one Purifi but double the cone surface (something that i can't measure but definitely has a subjective perceivable difference), better distribution of low frequencies, less doppler effect at same volume... In 50 liter cabinet, true.
What i consider true upgrades over rest of the midwoofers is flat frequency response - no ripple around 1kHz, no break up i can speak of, great off axis behavior. No resonances in the pass band. Finally someone tackled those known problems to the level of nonexistence. That to me is worth a lot more than lower distortion by level of highly questionable perceivability.
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I think the price must be so shocking that people are finding it challenging interpretting the data
Third comparison
Here's it again, @11.2V input
vs Satori MW16P-4 @2.83V input
In lay terms-
During rolling crescendos (eg. 32W input), this driver is cleaner than the Satori at 2W input!
Taking into account the difference in SPL sensitivity, at 10dB louder- it's still cleaner.
Incredible midrange
Incredible bass
Incredible dynamics
Third comparison
Here's it again, @11.2V input
vs Satori MW16P-4 @2.83V input
In lay terms-
During rolling crescendos (eg. 32W input), this driver is cleaner than the Satori at 2W input!
Taking into account the difference in SPL sensitivity, at 10dB louder- it's still cleaner.
Incredible midrange
Incredible bass
Incredible dynamics
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Multi driver comparison- is it even better than a 8" woofer WITH a 5" midrange?
1st pic- PTT bass frequencies
2nd pic- ScanSpeak 22W4851T bass frequencies
(bass frequencies matched for input voltage)
3rd pic- PTT midrange frequencies
4th pic- ScanSpeak 15M4531K midrange frequencies
(midrange matched for SPL)
1st pic- PTT bass frequencies
2nd pic- ScanSpeak 22W4851T bass frequencies
(bass frequencies matched for input voltage)
3rd pic- PTT midrange frequencies
4th pic- ScanSpeak 15M4531K midrange frequencies
(midrange matched for SPL)
Attachments
Ok so if the Purify PTT is that awesome should I now consider say 4 of them coupled with the new SB 3 inch dome midrange and a tweeter (to be determined) in sealed box using DEQX for crossover, or do I skip the dome midrange altogether and use 2 or 3 PTT as bass and 1 or 2 PTT as midrange and a tweeter? So experts how much of a game changer is this driver? Welcome comment from the tester and others
Out of curiosity. Do you see an advantage with DEQT over say Mini-DSP with Dirac Live ?
DEQX is brilliant no way would I downgrade to Mini-dsp - but you only get what you put into it hence getting the better drivers of Purify etc . Obviously Mini DSP has gotten a whole lot better.
I can't make a comment about the differences between the two brands, but I would say, no matter which one, the outcome will be down to the users ability to both use and tune the loudspeakers. If the active filter has no sound itself, then it does not matter which brands as long as you have full control. In reality it will probably have its own sounds signature, but that does not mean its bad. If you have equipment and you are happy with it, then there is no idea to "downgrade".
Honestly, I think the true value proposition of this driver is that it allows you to AVOID multi-driver arrangements. I really don't see an application where you'd need 4 of these per side, and even 2 might not be optimal when it comes down to it. If you need that kind of output, you're almost certainly better off augmenting with a multi-sub arrangement below 80Hz rather than pushing your mains down lower. Particularly considering the cost.
If you're in a domestic scenario where you absolutely can't add boxes, then I could see an argument for 2 per side - they'd have bass output similar to a pair of Anarchy drivers but with lower distortion, and 2xAnarchy is reportedly very satisfying for music. I'd still consider going with a true 3-way though - even something as (relatively) pedestrian as a RSS265HO handling sub-80 can be done in a small ported cabinet. (or a side-firing 12 if you want to go sealed - easy to do with a DEQX)
My real question is whether the overall system cost with the PTT will be all that much higher than some of the competitors. It seems like a pretty easy driver to work with, and hence you might save on the xover cost to some degree (probably not $150/side though). PTT + DA25 might be interesting.