Exploring Purifi Woofer Speaker Builds

I thought yours looked rather good. :)

Next step: all aluminum enclosure. :p

Model One

:confused:Not heard a speaker in an aluminium cab. You'd think it would ring like a big tuning fork - and I'm sure it doesn't - but I think my brain would keep telling me it is. I do appreciate the engineering there though, I like aluminium in domes (some people say zing - I say crisp), amongst other things.

This cab was whipped up fast with leftovers. I've got plans for cab. rev. 1 as this cabinet has some issues. 1. MDF. 2. Chuffing. Not that I can hear it with music but I can with sines, and I know its there so I need to fix it. 3. I prefer front ported.

This AMT is growing on me in other news.
 
Thanks ScottG. Looking at that Bliesma 34mm tweeter, and crossing it at 1.3-1.5khz with a (dreaming here) hypothetical 8" version of this purifi woofer, maybe getting a 35-40L vented box down to 30hz.. Camplo could scrap that 2-WAY high-SPL thread and have boxes that aren't the size of double refrigerators. Keep the Mrs happy and **** off the neighbours, those are goals #2 and #3 right? Still doesn't get you that "man need big, big is good" 15" woofer satisfaction.
 
..done right, a small array of the Peerless TC5FC00-04 might do just what you are looking for. ;)

The array will of course generate even less non-linear distortion for a given output level.

Best overall from 800-4 kHz with a good crossover. Excellent from 800-2 kHz.

Inexpensive (even in an array) as well! :)

If you don't mind metal, the the Peerless TA6FC00-04 is even better above 1 kHz.

Interesting. Can you please elaborate on how one might do this right? What kind of array are you talking about? How many drivers and in what configuration? Would it also need a bunch of tweeters?
 
Usually 4-6 drivers OFF-SET from the tweeter horizontally.

Typically a modest length *line source tweeter closer to the "outside" edge of the loudspeaker and close to that (yet nearer to baffle center) the array. Both above the midwoofer.

The larger Viawave would work very nicely and you could use the physical off-set (the tweeter being further away from the acoustic center of the array and woofer relative to the listener) in a crossover design similar to the Elsinore. I'd probably go cheaper and use the HiVi RT1.3 around 4 kHz and suffer the higher low-order distortion (..the higher order stuff should be suppressed because of the filter) on this tweeter.

*the line tweeter could also be an array of small dome tweeters (little or no face-plate) placed very near each other vertically.

You could go tweeter-less, but you'll loose some articulation/clarity - particularly with the paper 1.5". Of course both drivers will have some small amount of combing at the top, but with something like the metal driver's and proper acoustic loading - it tends to sound like a typical Electrostat.


Tim's measurements, and remember: the array will result in lower non-linear through decreased excursion for a given input level. (..and of course crossover filters tend to lower higher order distortion within the operating pass-band.)

Speaker driver measurements: 2-4" midrange, full range
 
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oh, I should note that my suggestion above is with respect to a more typical monitor construction.

For open-baffle, it really depends on if you use a baffle or go without.

Ex. I could "see" a no-baffle design with a vertical array of 8 of the 2" drivers above the tweeter (that's above the purifi as a midbass).
 
For a midrange MOrel MDM55 might do it, and then something like this on top OC20SC14-04 – Tymphany

:boggled: A $90 midrange and $9 tweeter for use with a $340 woofer? I'm lost on this part of the thread. Is it still referring to line arrays where the individual drivers need to be inexpensive or better yet cheap 'cuz we need to buy a bunch and then all hopes for distortion control are pinned to excursion reduction?
 
My impression is that the MDM55 is a very good midrange, especially for the price. But, I'm looking for an exceptionally good midrange and I'm willing to spend a fair amount on it. It seems, however, to be remarkably difficult to find a small driver with exceptional capabilities - especially HD - over the range of, say, 800 hz to 3Khz.

One would think, for example, that the Scan Speak 12M and 12MU would fit the bill, but if the data at HifiCompass is indicative, both are less than stellar in HD over that range. In fact, the SB15NBAC seems the best match to the PTT6.5.

I'll be quite happy if the PTT4.0 is as capable in the upper midrange as the PTT6.5 is below.
 
My impression is that the MDM55 is a very good midrange, especially for the price. But, I'm looking for an exceptionally good midrange and I'm willing to spend a fair amount on it. It seems, however, to be remarkably difficult to find a small driver with exceptional capabilities - especially HD - over the range of, say, 800 hz to 3Khz.

One would think, for example, that the Scan Speak 12M and 12MU would fit the bill, but if the data at HifiCompass is indicative, both are less than stellar in HD over that range. In fact, the SB15NBAC seems the best match to the PTT6.5.

I'll be quite happy if the PTT4.0 is as capable in the upper midrange as the PTT6.5 is below.

For spendy look at the accuton C50 2" mid range.

For not so spendy (actually quite very cheap and phenomenal off axis and wide dispersion, only matched by it's ugly looks) the BMR.

hifi compass has measured the Accuton C50 and the 2"BMR. There might be other independent measurements somewhere.

C50, 2nd and 3rd in the 800 - 4k under -55
Accuton C50-8-044 | HiFiCompass
Accuton C50-8-044 2" Ceramic Dome Midrange

The C51 looks even more impressive and of course more expensive, but don't know of any independent testing
Accuton C51-6-286 Ceramic Dome Midrange

BMR 2nd and 3rd is below 50 800-8k with a tiny blip above -50 around 2.5k, but still belwo -45. but check out the off aisx 30deg in the same frequency range.
Tectonic TEBM46C20N-4B | HiFiCompass

Have heard the C51 with hte RAAL 150-15 in the Vapor Perfect storm at Axpona, a few years back, the entire system was impressive, but this was at a show in a hotel room.
VAPOR AUDIO :: Exquisite Sound >> Perfect Storm White

Had Heard the 2" BMR in the Philaharmoic BMR monitor with RAAL 60-10 tweeter, again at Axpona some year, in a hotel room...
https://www.salksound.com/model.php?model=BMR+Monitors

But the credentials are there, regardless of the price for these mids.

I haven't tried any of these drivers, but i am wondering why am I waiting on the BMR's - those have a very low cost of entry...
 
woohoo! Got a shipping update that my woofers are on the way & will arrive Monday!

I sent them an email earlier this week to check on my order status & got a reply a day later saying it'd ship out on the 8th, but I guess they're running a bit ahead of schedule... cool.

I'm really really rusty on my speaker-building skills, so i think i'm gonna brush up on making circles w/ my router this weekend :) I haven't determined my xover points or hardware yet, so I guess i'll figure that out after. I happen to have a DCX2496 just sitting around along with both a hypex nc252mp & a Purifi EVAL1 setup. Once I get everything in the enclosure, I guess I can see how they sound in an active config, then try to mimic that w/ passive components.
Never done that before... sound like a good/bad idea?
 
My impression is that the MDM55 is a very good midrange, especially for the price. But, I'm looking for an exceptionally good midrange and I'm willing to spend a fair amount on it. It seems, however, to be remarkably difficult to find a small driver with exceptional capabilities - especially HD - over the range of, say, 800 hz to 3Khz.

One would think, for example, that the Scan Speak 12M and 12MU would fit the bill, but if the data at HifiCompass is indicative, both are less than stellar in HD over that range. In fact, the SB15NBAC seems the best match to the PTT6.5.

I'll be quite happy if the PTT4.0 is as capable in the upper midrange as the PTT6.5 is below.

audax pr170mo
 
..It seems, however, to be remarkably difficult to find a small driver with exceptional capabilities - especially HD - over the range of, say, 800 hz to 3Khz.

6 of these in series-parallel could get you what you want..
 

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A lot of midrange domes sound sort of "stunted" (full-depth impaired) in most applications. They are also less tolerant of excursion, meaning the high-pass needs to have more of a steep slope. Additionally, not a driver that will be used open-baffle. :eek:

They can of course offer excellent objective performance within their limits..


Ex. ATC-SM75-150S:
 

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All the VC windings. I wonder if that is intended to be like a TC Sounds LMS design with variable winding density linearizing the BL curve.

Looks like a Bimax spider - the ones I've worked with have a tendency to change a great deal with extended break-in.

That surround is wacky. Surely that can't be the only way to idealize the behavior of a surround. It reminds me of the profile of the woofer surrounds in the new Technics high-end tower speakers.
 
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