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PURIFI finally did a fully purified passive speaker design! The SPK 16 prototype is here - with a PTT tweeter

boXem said:
I guess that the 104 mm directivity is to be mated with 4" and 5.25" mid(woofer)s and the 147 mm with the 6.5"? Eventually the 8"?

In the SPK16 tech note, you explained that the wave-guide was optimized for both the tweeter and the box.
Will you provide an optimal box shape to be mated with the integrated wave-guide from both versions?
Click to expand...
My system has 2 8" purifi woofers and the 4" midrange, and as an upgrade path a sb26adc with a 4" waveguide (augerpro based) and the off axis behaviour matches reasonably well at xo of 3.4kHz (3-way active, acourate jpol11).
The purifi 104mm is fit-wise a drop in replacement, but its radiation is based on infinite baffle, so i already have the top portion of my enclosure replicated for measuring with foam and 3D print of baffle. (My enclosure weighs some 70 plus kilos;-))

Will be interesting project when they arrive!
 
we are waitting for price, in this days diy audio get some exited products but high prices, purifi's driver even be ordered by oem also expensive as hell.
 
JanRSmit said:
My system has 2 8" purifi woofers and the 4" midrange, and as an upgrade path a sb26adc with a 4" waveguide (augerpro based) and the off axis behaviour matches reasonably well at xo of 3.4kHz (3-way active, acourate jpol11).
The purifi 104mm is fit-wise a drop in replacement, but its radiation is based on infinite baffle, so i already have the top portion of my enclosure replicated for measuring with foam and 3D print of baffle. (My enclosure weighs some 70 plus kilos;-))

Will be interesting project when they arrive!
Click to expand...
Do you have some pictures you're willing to share?
 
Some pictures:
20250114_151656.jpg


Here a view from the kitchen into the livingroom:
20250201_160729.jpg


Last year may serious upgrade underway:
20240508_114232.jpg

Total height 113cm.
 
Did some digging in results of last year major upgrade and raw measurements of drivers in the enclosure to show that the 104mm tweeter (SB26ADC with 4" oval waveguide) could match quite well with a 4" PTT4.0M08-NAC04.
Here the Predicted In-Room-Curves as created in VituixCAD based on horizontal 10 degree step off-axis measurements 0-180 degrees:
M-T-Pirs-GAYA2-PIR-Study-01 CTA-2034.png

The violet curve is the SB26ADC with a 4" oval waveguide, the mint-blue is the PTT4.0M08-NAC4 . The XO Fs is 3464Hz, and acts in 2 octaves, so pretty steep (see the 3 markers). The shape of the baffle for midrange and tweeter are optimized with simulation with Akabak for a smooth off-axis response and wide as possible transition zone for the midrange.
To summarise, i hope the Purifi tweeter will give a similar "fit" at the XO range, be it with probably a more flat(horizontal) in-room response in the range above the XO. Fingers crossed :cool:
 
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Lars Risbo said:
the coming 147mm WG is optimised for the Spk16 box. we may do a larger (eg 176mm) that matches the 8” in a slightly bigger box. the current 104mm version is optimised for infinite baffle, not for a particular box shape.
Click to expand...
I received the 104 tweeters today and have only had a chance to test one outside a box, but it appears to operate as advertised in the higher frequencies. However, when I ordered my samples I was not aware that a larger version (the 147) was in the works and assumed that what I was receiving could be crossed at 1500 Hz or a little lower and might work with the 8" woofer in a large 2-way design. What is the lowest recommended crossover point for the 104?
 
Dear Dennis,

As you know, how low you go is a matter of SPL/dynamic range requirement.

I don’t think the IEC285 power handling has been completed yet; but I shall let Lars fill you in. As you may know, it is a particularly grueling test, based on 100 hours continuous power with a shaped sine wave without damage. The AES is a little gentler, at only 2 hours without damage.

Based on lab grade distortion measurements taken of a prototype, my calculations is that

it can handle a HPF for acoustic LR4@1KHz with SPL of 110dB
With the crossover in place, at @110dB over 2-10KHz), at 500Hz, H2 is about -48dB; H3 is -50dB. Whether that SPL is high enough for you, or distortion low enough for you, depends on your intended application, of course.

BUT, don't forget that maintains a wide dispersion like a tweeter without a WG, but behaves with constant directivity like a tweeter with a waveguide, and plays as low as a tweeter with a WG.


You can have your cake, and eat it too!

best regards,
Thanh
 
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tktran303 said:
Dear Dennis,

As you know, how low you go is a matter of SPL/dynamic range requirement.

I don’t think the IEC285 power handling has been completed yet; but I shall let Lars fill you in. As you may know, it is a particularly grueling test, based on 100 hours continuous power with a shaped sine wave without damage. The AES is a little gentler, at only 2 hours without damage.

Based on lab grade distortion measurements taken of a prototype, my calculations is that

it can handle a HPF for acoustic LR4@1KHz with SPL of 110dB
With the crossover in place, at @110dB over 2-10KHz), at 500Hz, H2 is about -48dB; H3 is -50dB. Whether that SPL is high enough for you, or distortion low enough for you, depends on your intended application, of course.

BUT, don't forget that maintains a wide dispersion like a tweeter without a WG, but behaves with constant directivity like a tweeter with a waveguide, and plays as low as a tweeter with a WG.


You can have your cake, and eat it too!

best regards,
Thanh
Click to expand...
And I'm sure it's an excellent cake. I just don't want to design a speaker that will be, from a marketing standpoint, obsolete in 6 months.
 
Ah marketing... that bloody double edged sword.

We need to talk to someone in marketing/sales to convince them to sell Lars' comprehensively designed WGs, separately from the tweeter motor/dome assembly...

We like all kinds of cake...
 
Dennis Murphy said:
And I'm sure it's an excellent cake. I just don't want to design a speaker that will be, from a marketing standpoint, obsolete in 6 months.
Click to expand...

Seems to me the use case for the smaller tweeter is in a 3-way with a small mid, whereas the bigger WG would be for 2-ways with medium size midwoofers.

And IMO it would be a huge upgrade from a long, skinny wiggling tinfoil strip - a speaker with wide horizontal dispersion that doesn't turn in to a dull bore when you stand up.
 
hi Dennis, as it has been mentioned, the power handling does not change with the waveguide. The larger waveguide is just to shape the dispersion pattern to match larger mid/bas drivers. We also offer to do custom designed waveguides for glove fit to particular designs/box shapes. There will likely be multiple WG options in the future. Let’s continue on email and see if we can help you achieve your goals.

cheers

Lars
 
@jhaider

LOL your prejudice shows through!

I like “long skinny wiggling tinfoil strips” as much as fat circular wobbly bits of paper/plastic/metal driven by bits of wire wrapped around toilet rolls, surrounded by flabby bits of rubber.

You should give them a listen to them sometime!
 
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