So who (else) is waiting for 12" or 15" super-woofers from Purifi?
On one hand, we have the PA companies e.g. JBL, B&C (or subsidiaries ie. 18 Sound, now Eminence), RCF, BMS etc, who have been offering larger woofers 15" to 21", generally with higher sensitivity, higher power handling. Well they are ok for BR cabinets for maximum SPL from 40Hz to 120Hz for crowds 10m away. Sometimes they offer a variant with a neo magnet for weight reduction, which helps the customer for portability/transport. So that's nice. But they all have raggedy frequency responses.
On the other hand, we have "hi-fi" manufacturers who offer products with a much smoother frequency response, but generally lower sensitivity/power handling. In all manner of sizes from 3" to 15" drivers. Like the ovoid 84mm dome or 15" cone with pricing that matches your local jeweler.
But if someone can release a 12" or 15" woofer with smooth frequency response AND high power handling, it's @lrisbo and Carsten Tinggaard. With an optimized cone geometry, optimised soft parts (spider and surround) and magnificent motor system, it could play smoothly on and off axis to ~1.1KHz or ~ 900Hz respectively (-6dB, +/- 45° beamwidth). And despite having ~15-20 mm excursion, it will have minimal distortion of all kinds.
Is this in the pipeline? @lrisbo
Or just a pipedream for the lovers of bigger woofers? @vineethkumar01 @kipman725 @CharlieLaub
On one hand, we have the PA companies e.g. JBL, B&C (or subsidiaries ie. 18 Sound, now Eminence), RCF, BMS etc, who have been offering larger woofers 15" to 21", generally with higher sensitivity, higher power handling. Well they are ok for BR cabinets for maximum SPL from 40Hz to 120Hz for crowds 10m away. Sometimes they offer a variant with a neo magnet for weight reduction, which helps the customer for portability/transport. So that's nice. But they all have raggedy frequency responses.
On the other hand, we have "hi-fi" manufacturers who offer products with a much smoother frequency response, but generally lower sensitivity/power handling. In all manner of sizes from 3" to 15" drivers. Like the ovoid 84mm dome or 15" cone with pricing that matches your local jeweler.
But if someone can release a 12" or 15" woofer with smooth frequency response AND high power handling, it's @lrisbo and Carsten Tinggaard. With an optimized cone geometry, optimised soft parts (spider and surround) and magnificent motor system, it could play smoothly on and off axis to ~1.1KHz or ~ 900Hz respectively (-6dB, +/- 45° beamwidth). And despite having ~15-20 mm excursion, it will have minimal distortion of all kinds.
Is this in the pipeline? @lrisbo
Or just a pipedream for the lovers of bigger woofers? @vineethkumar01 @kipman725 @CharlieLaub
John @ AE does do commendable work with his line of woofers, particularly the TD series, which have full copper sleeve and a smaller lightweight VC for higher sensitivity.
I was thinking more along the lines of things with an outer diameter of 308mm or 315mm to replace 12" XLS/NE or 15" SDF/STW products from Tymphany, a brand that seems to have left the DIY market. Things with the full suite of Purifi processes, now aptly named Ushindi technologies. This includes the variable winding on the voice coil, and the funky surround, for low Le(x) and Sd(x) variation, amongst other things.
I'm certain Lars and Carsten continue to work behind the scenes to look at other sources of distortion. Moving parts that are soft, eg. spider, seem ripe for improvement, in my view.
I was thinking more along the lines of things with an outer diameter of 308mm or 315mm to replace 12" XLS/NE or 15" SDF/STW products from Tymphany, a brand that seems to have left the DIY market. Things with the full suite of Purifi processes, now aptly named Ushindi technologies. This includes the variable winding on the voice coil, and the funky surround, for low Le(x) and Sd(x) variation, amongst other things.
I'm certain Lars and Carsten continue to work behind the scenes to look at other sources of distortion. Moving parts that are soft, eg. spider, seem ripe for improvement, in my view.
What about the Driver used in Gedlees NS15? Seems to be fitting for the designer who is known for his high standards... What about the Jbl m2... Actually almost every one of the major PA woofer manufacturers has at least one or two woofers that are highly prized... or no? If I get what you are saying, I think I agree... I have an td15m and it should be a good representative with its slightly lower mms via 16ohms voice coil and its FR towards break up isn't "perfect"... I guess the question is can a 15" Purifi woofer Best it??? and to @Jonasz point would it be so much better that its extreme cost would warrant it? Even the prices of AE and the other PA woofers has gone up....
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I hope this is a reasonable place to pose this quick question (or two)...
This is a Purifi PTT6.5X04-NFA in a 38 mm (1.5") thick baffle. The through hole is 145 mm. I was planning on chamfering the back side at 22.5 degrees. But this looks like plenty of space. Does it need more space to breathe?
Related to this, I've been thinking about isolation approaches to driver mounting, some of which are a bit easier to accomplish using through-holes on the baffle with the back face of the baffle being flat where the holes come through. Thus, the question of whether a back chamfer is needed. I get the sense here (including Lars' post #1780, counseling to torque mounting screws properly and focus on other aspects) that driver isolation might not be worth the trouble. I may have some isolation of the baffle from the enclosure because this is a solid wood baffle on a plywood box, and so the baffle will be gasketed and retained in a manner that allows for small movements. Any guidance?
This is a Purifi PTT6.5X04-NFA in a 38 mm (1.5") thick baffle. The through hole is 145 mm. I was planning on chamfering the back side at 22.5 degrees. But this looks like plenty of space. Does it need more space to breathe?
Related to this, I've been thinking about isolation approaches to driver mounting, some of which are a bit easier to accomplish using through-holes on the baffle with the back face of the baffle being flat where the holes come through. Thus, the question of whether a back chamfer is needed. I get the sense here (including Lars' post #1780, counseling to torque mounting screws properly and focus on other aspects) that driver isolation might not be worth the trouble. I may have some isolation of the baffle from the enclosure because this is a solid wood baffle on a plywood box, and so the baffle will be gasketed and retained in a manner that allows for small movements. Any guidance?
I think the Purifis are superior and unique as midwoofers for usual hifi speakers with dome tweeters, and when you aim for wide bandwith with high level/excursion from small drivers and enclosures there is currently no alternative.
The OEM market loves this, and you find that in the Purifi product portfolio: Lots of variants for typical 4", 5" and 6.5" sizes. Just 2 variants for 8" size, as you will need waveguide for tweeter to match directivity. All larger sizes above may by only selected for woofer duty, just to their size and accordingly dispersion characteristics by principle.
Would I trade my 2x 10" Scan Speak Discovery woofers filtered <300Hz LR4 for 1x Purifiy 10" of ~4x the price, for duty in a floorstander with the same footprint? Probably not, for that use case it gives me not much advantage regarding the price. Even two 10" Revelators with pretty long stroke and very clean distortion profile are cheaper.
Below <100Hz for subwoofer duty there are even more alternatives that can move a lot of air nice and noisefree in a range were distortions are even not perceptible.
In my opinion, for pure woofer duty the Purify technology is oversized and therefore too expensive. Market for 12"-15" midwoofers (e.g., paired with compresion drivers and horns) is very small, and prefers "high efficiency" drivers for the guys with tube and class A amps.
For woofer/subwoofer duty there is a wide market from the PA driver manufacturers, and even this beast is significantly cheaper than 10" Purifi: https://www.bmsspeakers.com/fileadmin/bms-data/product_data_2012/bms_18n862_t_data_2012-02.pdf
I fear the Purify guys may see this similar, and if they would launch a 12" or 15" then only because they can but not hoping for good business and revenue.
An alternative could be to they strip the technology down for pure woofer duty to achieve lower prices, but then their capabilities are not more unique and they no longer stand out from the competition...
If you can, give it the chamfer. It's not just about breathing, but about minimizing a pipe resonance due to the thick baffle.
Need some advice... I have a pair of Jern 14EH speakers but I don't know what the internal volume is. I am extremely tempted to try a Purifi 5.25 in the place of the ScanSpeak 15W 8424 as they have somehow close mechanical and electrical parameters though the Purifi has a much larger magnet. Is it a really silly idea, what would be the lowest possible sealed volume that the 5.25" is OK with, can anyone please advise?
the PTT5.25 has a very strong motor compared to Sd so it can really compress air in a very small sealed volume such as 1-2L. However, this may push fs and Qts above what you want (this is where the Linkwitz Transform is brilliant for an active speaker). our web shows sealed volume for Butterworth (Qtc =0.707)