Purifi PTT6.5W04-01A 6.5" midwoofer

[oivavoi]

I read it somewhere. They actually start straining when pushed over 90dB. Do some modelling on the midrange and see what you can come up with. It's a $3 mid at wholesale pricing. What do you expect? 10W power handling with 82dB-78dB efficiency above 1000hz.

https://www.parts-express.com/tecto...MIq5Hj7ITW5QIVQiCtBh2bIAUwEAQYAiABEgKx7PD_BwE

Are you sure it's that one and not the 3 1/2 inch bmr driver, which has somewhat higher efficiency and power handling? I would anyway like to see proper measurements.

 

[Audiocrusader]

Are you sure it's that one and not the 3 1/2 inch bmr driver, which has somewhat higher efficiency and power handling? I would anyway like to see proper measurements.

Yes sorry wrong driver:

https://www.parts-express.com/pedocs/specs/297-2157--temb46c20n-4b-2-spec-sheet.pdf

But still not much of a powerhouse. Let's see measurements that matter such as distortion over 100dB. It's easy to wow audiophiles with things that matter the least.

 

[Audiocrusader]

I recently purchased a Dscope M1:

http://www.prismsound.com/test_measure/products_subs/dscope_m1/dscope_m1_home.php

And Loudsoft (the best loudspeaker software available) has collaborated with Spectral to use this analyzer as a precision hardware platform for measurements.

https://www.loudsoft.com/about-loudsoft/

So can't wait to start busting audiophile myths.

 

[617]

It's been 10 years since I last DIY a speaker from scratch. What's the best online calculator these days?

WinISD for boxes, VituixCAD for network design, 3d simulation, diffraction modelling, room modelling.

 

[Audiocrusader]

WinISD for boxes, VituixCAD for network design, 3d simulation, diffraction modelling, room modelling.

The best of everything here. Crossover design, box design, measurements.

https://www.loudsoft.com/products/

 

[Audiocrusader]

If anyone can recommend a neo magnet 6.5" woofer to test let me know. We can see if the best neo magnet 6.5-7" drivers can outperform the Purifi woofer with it's lowly ferrite magnet.

 

[Audiocrusader]

Interesting post on the BMR drivers. Good thing 99% of folks who bought those speakers don't have the gear to measure them:

https://www.diyaudio.com/forums/mul...ts-tebm46c20n-4b-bmr-3-range.html#post5040409

 

[Wombat]

The best of everything here. Crossover design, box design, measurements.

https://www.loudsoft.com/products/

The request was for online calculators.

For example: http://www.micka.de/en/

or these: https://www.madisoundspeakerstore.com/calculators

 

[Audiocrusader]

The request was for online calculators.

For example: http://www.micka.de/en/

My mistake. Loudsoft would likely be too accurate and comprehensive.

 

[DDF]

The reason he chose that Scan-Speak woofer was because it's cheap. Not because it's better than newer alternatives. However it's still a pretty decent woofer even though it's a 23 year old design.

I've design extensively with this driver. It's fine but long superseded in the mids by more modern drivers. See Linkwitz's (RIP) driver characterizations:
https://www.linkwitzlab.com/mid_dist.htm
It has a surround cone edge termination problem ~ 900Hz. Denis wondered aloud online whether it should be dealt with in the xover (his older designs didn't). It should (I did, to markedly not subtle effect). But when used frequency restricted as Denis did (600Hz) with the BMR, its still a nice driver. I love its lack of a significant break up peak that hard cones show. Decent trade offs.

To avoid being a distortion magnifier (or PITA to design around off axis), and any hard breakup is ideally > 1 octave up from the 20 dB down point of the xover, IME. Another thing I like about the Purify is its lack of a shotgun break up peak (see below)

Something the same sized (W18EX) SEAS hard cones can't claim

 

[617]

I've design extensively with this driver. It's fine but long superseded in the mids by more modern drivers. See Linkwitz's (RIP) driver characterizations:
https://www.linkwitzlab.com/mid_dist.htm
It has a surround cone edge termination problem ~ 900Hz. Denis wondered aloud online whether it should be dealt with in the xover (his older designs didn't). It should (I did, to markedly not subtle effect). But when used frequency restricted as Denis did (600Hz) with the BMR, its still a nice driver. I love its lack of a significant break up peak that hard cones show. Decent trade offs.

To avoid being a distortion magnifier (or PITA to design around off axis), and any hard breakup is ideally > 1 octave up from the 20 dB down point of the xover, IME. Another thing I like about the Purify is its lack of a shotgun break up peak (see below)
View attachment 38079
Something the same sized (W18EX) SEAS hard cones can't claim
View attachment 38080

You may like the SB acoustics MFC drivers, a complete joy to work with.

 

[DDF]

You may like the SB acoustics MFC drivers, a complete joy to work with.

Thanks. I used to use the 18W8543 ~30 years ago (after years of the Vifa Polys) but not sure I'm ready to step back to poly. I agree they are dreamy to work with though.

 

[watchnerd]

It would be interesting to see the Purifi measured versus this:

https://www.madisoundspeakerstore.c...nspeak-illuminator-18wu/8741t-7-woofer-8-ohm/

https://www.scan-speak.dk/datasheet/pdf/18wu-8741t00.pdf


Similar Fs, Xmax.

It's not new, by any means.

There used to be Kippel test data for it on the web, but my bookmarks for them have become 404s.

 

[Audiocrusader]

It would be interesting to see the Purifi measured versus this:

https://www.madisoundspeakerstore.c...nspeak-illuminator-18wu/8741t-7-woofer-8-ohm/

https://www.scan-speak.dk/datasheet/pdf/18wu-8741t00.pdf


Similar Fs, Xmax.

It's not new, by any means.

There used to be Kippel test data for it on the web, but my bookmarks for them have become 404s.

Aluminum cone version. There's also the paper review if I can find it.

http://www.audiocomponents.nl/download/scan-speak/18WU-4747T00 - Voice Coil 2010-4.pdf

Not even close.

 

[Audiocrusader]

Here's the paper cone version. Wow distortion is through the roof!

http://www.audiocomponents.nl/downl...741T00 & 18WU-4741T00 - Voice Coil 2009-2.pdf

 

[Thomas savage]

Keep it civil and constructive please.. thanks .

 

[watchnerd]

Here's the paper cone version. Wow distortion is through the roof!

http://www.audiocomponents.nl/download/scan-speak/15WU-4741T00 & 18WU-4741T00 - Voice Coil 2009-2.pdf

Well....

The Voice Coil test seems to show a test at 115 dB at 1 kHz, with 2nd harmonics at ~ 74 dB.

The Purifi datasheets shows better numbers.....for a test at 90 dB at 1 kHz.

If Purifi was publishing similar numbers at 115 dB, you might have a point. But based on just those data points, I wouldn't call it conclusive, by any means.

You wanted a neodymium based woofer to test against, that would be a good one. It's been around a while, but has been used in designs like the Wilson Sofia.

 

[Audiocrusader]

Well....

The Voice Coil test seems to show a test at 115 dB at 1 kHz, with 2nd harmonics at ~ 74 dB.

The Purifi datasheets shows better numbers.....for a test at 90 dB at 1 kHz.

If Purifi was publishing similar numbers at 115 dB, you might have a point. But based on just those data points, I wouldn't call it conclusive, by any means.

You wanted a neodymium based woofer to test against, that would be a good one. It's been around a while, but has been used in designs like the Wilson Sofia.

You must be misreading the plots. He said that the SPL was set at 94dB for the distortion test.

 

[watchnerd]

You must be misreading the plots. He said that the SPL was set at 94dB for the distortion test.

So maybe the Purifi would do quite a bit better, then.

But it would still be good to see a head to head under same test conditions.

First rule of thumb is that all manufacturer spec sheets are marketing materials and should be validated with independent tests.

 

[Audiocrusader]

So maybe the Purifi would do quite a bit better, then.

But it would still be good to see a head to head under same test conditions.

First rule of thumb is that all manufacturer spec sheets are marketing materials and should be validated with independent tests.

Well the exact same suite of tests will be performed on the Purifi woofer when Voice coil gets them. However the Purifi team isn't a bunch of chumps who would publish the most comprehensive measurement data ever published in a driver datasheet, knowing that it would just be debunked shortly after with independent tests. They sell these drivers to professionals who have the gear to measure them.