Purifi PTT6.5W04-01A 6.5" midwoofer

[Audiocrusader]

Pretty decent CV.

http://en.pointsource.dk/wp-content/uploads/2014/01/101214-Rev4-CV-Carsten-Tinggaard.pdf

 

[617]

It is starting to feel a bit like a crusade to be honest. I don't even design speakers with midwoofers. The midwoofer is the Toyota Camry of transducers.

 

[Wombat]

Restorer John doesn’t like class D amps because none over them ever make it to his bench for repair. They’re too reliable.

 

[Audiocrusader]

It is starting to feel a bit like a crusade to be honest. I don't even design speakers with midwoofers. The midwoofer is the Toyota Camry of transducers.

Well if you want to sell speakers to anyone under 60 and doesn't wear a pocket protector, the 2 way is the way to go moving forward. Besides there's several drawbacks to trying to seamlessly integrate 3 drivers. You'll never get as seamless of integration as a 2 or 2.5 way.

 

[Audiocrusader]

If that's not true, how many Icepower, Hypex, or Purifi amps have landed on his desk? Hard to make money repairing products that never break. Or that would cost less to replace than pay someone to repair. Very bad for business for some I can imagine.

 

[Wombat]

Point 1 is interesting.

Point 2 however I don't agree with. "traditionally" the spider was less suspension and more voice coil centering. The surround offered considerable additional suspension. Take a traditional speaker with no surround and drive it. See what happens. The spider was traditionally also placed much closer to the pole piece. This driver is like the Seas driver Wombat linked with the spider halfway along the basket arms, almost 50% along the cone.

I can also recall numerous drivers using helix-like surrounds, no surrounds at all, pleated, angled, channeled and shaped, all in the interests of linear excursion over the entire stroke and cone to surround interfacing to reduce distortion. It's hardly new.

Note diaphragm position in the Polk drawing shown here: https://www.audioholics.com/loudspeaker-design/loudspeaker-drivers

Harman spider patent for distortion reduction: https://patents.google.com/patent/US20050008188

The purify list of distortions did not mention increased Doppler distortion that comes with larger cone travel.

 

[Killingbeans]

I'm going to bed now. Hope there's more than smouldering ashes left when I get up

 

[Audiocrusader]

The purify list of distortions did not mention increased Doppler distortion that comes with larger cone travel.

One of the key design elements of this driver is highly reduced distortion at large cone travel.

 

[restorer-john]

Well if you want to sell speakers to anyone under 60 and doesn't wear a pocket protector, the 2 way is the way to go moving forward. Besides there's several drawbacks to trying to seamlessly integrate 3 drivers. You'll never get as seamless of integration as a 2 or 2.5 way.

You know I love little 6.5" 2 way speakers. I've got a ton of them, all different brands, pedigrees and prices. There's at least 8 pairs in my loungeroom gathering dust and one pair on stands to listen to. They are fun and easy to compare (lightweight and easy to move) and produce a lot of sound from a small size.

But full range they are not. The mid band can be anything from very good to just OK. Real bass? Forget it. Power handling? forget it. Dynamic compression from VC heating- count on it- in spades.

 

[restorer-john]

The purify list of distortions did not mention increased Doppler distortion that comes with larger cone travel.

Sssh. It's a magic woofer. These aren't the droids you are looking for...

 

[Wombat]

Pretty decent CV.

http://en.pointsource.dk/wp-content/uploads/2014/01/101214-Rev4-CV-Carsten-Tinggaard.pdf

I was referring to your comments re member's responses..

 

[Audiocrusader]

 

[Audiocrusader]

You know I love little 6.5" 2 way speakers. I've got a ton of them, all different brands, pedigrees and prices. There's at least 8 pairs in my loungeroom gathering dust and one pair on stands to listen to. They are fun and easy to compare (lightweight and easy to move) and produce a lot of sound from a small size.

But full range they are not. The mid band can be anything from very good to just OK. Real bass? Forget it. Power handling? forget it. Dynamic compression from VC heating- count on it- in spades.

Yes I can imagine this is the case as they use outdated drivers from yesteryear. For home theatre the modern solution is adding active subs.

 

[Wombat]

View attachment 37916View attachment 37917View attachment 37918View attachment 37919View attachment 37920View attachment 37921

My comment was that Doppler distortion was not mentioned in the list of the distortions shown in the OP link. You have just shown another
reference that doesn't mention it. Well done. Thank you.
If you find information on the driver's Doppler distortion, let us know.

For the record I have not said that this is a poor driver. I am sceptical of the hoo-ha.

 

[617]

Do you need more comments from us to keep going or can I go to bed?

 

[restorer-john]

Yes I can imagine this is the case as they use outdated drivers from yesteryear. For home theatre the modern solution is adding active subs.

Outdated drivers. Yes of course, and here I thought you were talking about my Windows installation.

Active subs eh? There's a pair of active PSBs here, a pair of active Mirage subs, a JBL active and a Bowers and Wilkins AS-600 also gathering dust. I've had enough of subwoofers- for 2ch music there's nothing to touch a big pair of 3 ways.

Do you need more comments from us to keep going or can I go to bed?

OK, off you go, that lingerie model and her friends will only wait so long...

 

[Audiocrusader]

My comment was that Doppler distortion was not mentioned in the list of the distortions shown in the OP link. You have just shown another
reference that doesn't mention it. Well done. Thank you.
If you find information on the driver's Doppler distortion, let us know.

For the record I have not said that this is a poor driver. I am sceptical of the hoo-ha.

The Doppler distortion is the main improvement achieved by this design. Is there an industry standard Doppler distortion spec shared by any driver manufacturers?

Distortion caused by excursion is Doppler distortion. This is explained precisely in these charts:

 

[Audiocrusader]

for 2ch music there's nothing to touch a big pair of 3 ways.

Yes I believe you when you say this is the case with what you have experience with.

 

[Wombat]

The Doppler distortion is the main improvement achieved by this design. Is there an industry standard Doppler distortion spec shared by any driver manufacturers?

Distortion caused by excursion is Doppler distortion. This is explained precisely in these charts:

View attachment 37923

So you can see reduced Doppler distortion in figure 9. How did you manage to extract the Doppler distortion let alone see it has been reduced?

 

[DDF]

None of Purify's refinements are about Doppler distortion. They are magnetic and suspension improvements. In the name of science (go figger), this is doppler distortion in loudspeakers:
http://web.archive.org/web/20090809205449/http://www.geocities.com/kreskovs/Doppler1.html