tf1216 thanks for the heads up. Copy-paste from the new driver's page NEW! PTT6.5W04-NFA-01 - PURIFI reveals what this is about:
"The PTT6.5W04-NFA-01 is a standard-stroke version of PURIFI’s Ultra Low Distortion 6.5” Woofer family. As compared to the extended-stroke PTT6.5X04-NFA-01 (aka PTT6.5W04-01) the efficiency has been improved while reducing the linear stroke a few millimeters."
Just the thing for you misguided souls who insist on using (shudder) a woofer below a PTT6.5.
Or for the cool dudes into tube amps. 
I like what ASR is doing for the community and the hobby, but reading for a few years now he comes across as quite the selfish individual IMO. He smashes out so many reviews, his overall presentation is lacking compared to say, hardisj/Erin and there’s another there I forget the name of that’s good too. You’d think by now with all his donations and tech he would’ve taken on some colleagues or apprentices to help out and lift the quality some. He never seems interested in letting anyone challenge or even assist him. I hope im proven wrong.
Anyway, off topic rant over, back to purifi stuff.
As posted earlier, wonder what’s up with the model number changes on their drivers? And also, anyone notice the TS specs changed? I’d swear the QMS was higher when I bought mine... not that it changes the modelling much. I guess that happens often when material suppliers change.
EDIT, ah I see Norman answered already I missed that ...
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Purifi advertises "Low Surround Radiation Distortion". I wonder if all we need to do to achieve same, for any driver, is to avoid running the driver into the region where the surround is not completely in phase with the cone? I'd be surprised if surround breakup or anti-phase behaviour wouldn't show up on a CSD.
For example, with the Satori paper cone drivers which have a well-known and easily-visible cone edge resonance somewhere around 1 kHz - what if we just cut off below there (assuming the crossovers/speaker configuration allows)?
EDIT: Actually, I'm seeing now some peaks in HD below the resonance that look like they might be associated with it... I guess another reason to stick with metal cone drivers!
For example, with the Satori paper cone drivers which have a well-known and easily-visible cone edge resonance somewhere around 1 kHz - what if we just cut off below there (assuming the crossovers/speaker configuration allows)?
EDIT: Actually, I'm seeing now some peaks in HD below the resonance that look like they might be associated with it... I guess another reason to stick with metal cone drivers!
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Just the thing for you misguided souls who insist on using (shudder) a woofer below a PTT6.5.
I guess Purifi are a business after the all. The customer is always right.
"Too low sensitivity" OR
"I want one for midrange use"
From my point of view; the original PTT6.5 driver has better bass than many 8", or even 9-10" drivers, and a midrange that leaves nothing against the best 5" drivers. And all in a 15-20L box.
No sweat reaching 100dB with 12V input (40W in 4 ohms): Klippel verified here: Purifi Audio PTT6.5W04-01A 6.5 Inch Woofer Review
For running full tilt @100W applied and 10 mm x-max you can reach 105dB per speaker. In stereo that's 110dB.
Even at 90dB average (LOUD!) I've got the 20dB of "headroom" for the peaks...
So basically you have a speaker smaller than a typical 6.5" 2 way but as good or better than a 8/5/1" 3-way. And you only need 40-100W (into 4 ohms to achieve it); easily achievable by a good solid state or class D amplifier.
The distortion levels are vanishingly low, I couldn't figure out what was going on- turns out I hadn't turned the screws all the way in for the tweeter!
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Just the thing for you misguided souls who insist on using (shudder) a woofer below a PTT6.5.
Even if the woofer is one of these?
An externally hosted image should be here but it was not working when we last tested it.
Maybe..
......crossed over below 30-40 Hz as REL pioneered.That's a beefy fellow.
I have a pair of subs using 2 each long excursion 10" drivers in sealed too small (= overdamped, the way I prefer to error) enclosures. I brief experiment using them below my Fi16s was fun and something to return to one day.
I had a quad of 10" woofers powered by 1kW per side, with anechoic F3 of 23Hz. Lower distortion than the SDX-10 but also lower excursion (12mm vs 18mm)
I had it dialled in for an in-room response down to below 20Hz. It probably went lower but microphone is not accurate to the single digits.
They are good for shaking walls down with dinosaur stomps, explosions, rocket launches, and mortars going off but for music I turn them off.
Sometimes it's good to try these things just to experience it. So you know you never needed it.
I had it dialled in for an in-room response down to below 20Hz. It probably went lower but microphone is not accurate to the single digits.
They are good for shaking walls down with dinosaur stomps, explosions, rocket launches, and mortars going off but for music I turn them off.
Sometimes it's good to try these things just to experience it. So you know you never needed it.
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For info, looks like you can get them here at $108 each.
Fostex 8578100100 Woofer For NX-6A | Full Compass Systems
And review of the NX6a speaker they come from.
Fostex NX6A
Fostex 8578100100 Woofer For NX-6A | Full Compass Systems
And review of the NX6a speaker they come from.
Fostex NX6A
Well if anyone thought the purifi looked weird, I’m not going to say what that fostex looks like. Would love to see some response and distortion plots, quick googling looks like it was from an active monitor that wasn’t very successful.
Has anyone purchased the new 6.5 higher sensitivity purifi woofer or the not so new 4” woofer? Any luck with builds or ideas? I realise it may be a bit soon but would love to hear your experiences
Has anyone purchased the new 6.5 higher sensitivity purifi woofer or the not so new 4” woofer? Any luck with builds or ideas? I realise it may be a bit soon but would love to hear your experiences
Glad someone got these. I was eyeing them but I am in Europe. These are awesome. Leave them full range and add tweeter first order at 10khz as Fostex does with the NF1 passive. Or use them up to 5-8-10kHz with whatever crossover you prefer.
The NX6 was not successful but not because of lack of quality. Don’t underestimate this $1400 pair (back then) of monitors or its woofer because you got a spare for $20 - you just got bargain deal. Even at $100 they are still deal.
The FW168hr cousin is €415/$500 (in Europe-audio) and the new Japanese Alnico mode with the same technology is like $2000 🥸
The FW168hr woofer with the same technology: https://www.fostexinternational.com/docs/speaker_components/pdf/fw168hprev.pdf
I have a few pairs of the NX6 monitors and the original NF1 versions. They are worth it. And the woofers are way higher quality than most of Fostex’es speakers for diy lines.
Here are t/s parameters of the woofer of the NF1. I believe this one will be quite similar:
Fs = 55, Hz
Qms = 2,183
Vas = 10,71 liters
Cms = 0,589 mm/N
Mms = 14,21 g
Rms = 2,249 kg/s
P-Dia = 120, mm
Sd = 113,1 sq.cm
Qes = 0,487
Re = 6,2 ohms
Z = 8, ohms
BL = 7,906 Tm
Qts = 0,398
no = 0,353 %
1-W SPL = 87,68 dB
2.83-V SPL = 88,78 dB
Hope that helps
I picked up 4 of the 4" drivers with plans to build a pair in a 2.5 way TMM using the Scanspeak Illuminator Beryllium tweeter on the high end. I'll be mounting these on some floating shelves for use in my business. The 4" models well with a pair of the matching PRs so I have eight of those (four per box, two per driver). Fingers crossed!
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Troels Gravesen has posted his review of the Purifi Audio PTT6.5W04. 6 inch, 4 Ohm driver.
Purifi_PTT6.5WO4
Nice close-up pics showing some of the PTT6.5's unique features.
Purifi_PTT6.5WO4
Nice close-up pics showing some of the PTT6.5's unique features.
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