Selah Audio Purezza Review

[HooStat]

The main advantage is greater output capability

Sorry to ask a naive question, but I assume that this is different from sensitivity? I am guessing that because of the lower distortion, even though it isn't the most sensitive speaker, it can be pushed harder and therefore is potentially louder?

 

[Ericglo]

Me trying to justify a purchase

You and me both. Rick and Dennis make it hard, because they keep upping the ante with newer speakers.

 

[Rick Sykora]

This is a project for Jim Salk, and I should have the test cabinet with drivers next week. We'll see--sometimes these newfangled audio thingies don't quite live up to their promise. At least I didn't have to pay for these puppies. Anyhow, back to more affordable Purifi designs.

sounds like a good reason for a new thread!

 

[Selah Audio]

Great review as usual.

Very interesting design decision to use that passive radiator. I remember sending him nearfield measurements of mine last year which might have piqued his interest. I'd be curious to hear more about why he ended up choosing it over a vented design. My guess is it allowed for a smaller cabinet which matched well with the active woofer, or even to allow closer placement to the front wall as he alluded to with his BSC. Basically, the same reasons it was chosen by Buchardt Audio. Rick may have other reasons.


Indeed, however another thing a waveguide would do is to broaden the high-frequency dispersion. Notice that the ribbon starts to beam above 10 kHz whereas a waveguide would maintain a more constant directivity throughout the whole tweeter range to 20 kHz. Tradeoffs. Example with waveguide (Buchardt S400):

View attachment 81924

I had similar thoughts since I use XT32 to flatten and linearize the bass region but maybe it doesn't matter to us as much. Perhaps making the speaker work well for those not using room correction is the right approach.

Just a guess – likely because you'd have to use 2 of them to get enough area which would be challenging to fit and not increase the size of the speaker.

I don't remember receiving any nearfield measurements. Maybe it was someone else?

 

[Chromatischism]

I don't remember receiving any nearfield measurements. Maybe it was someone else?

At AVS.

 

[Selah Audio]

Maybe the racetrack passive radiator allowed for a smaller box?

Hificompass has a clever design that uses 2 of the Purifi passive radiators on opposite sides to reduce vibrations, plus a diagonal sound barrier. But it does look bigger.

View attachment 81936View attachment 81937

https://hificompass.com/en/projects/2-way-systems/puri-bliss-bewg

I don't remember exactly what the cabinet volume was with the dual PR's but I don't think it was that different.

 

[Bruce Morgen]

Rick -- Please pardon me if this is an ignorant or naive question, but why the apparent 4 dB difference in sensitivity between the factory spec for the woofer and the Purezza's corresponding number? Is that from the effect of the enclosure and PR vs. a free air measurement?

 

[Ilkless]

Rick -- Please pardon me if this is an ignorant or naive question, but why the apparent 4 dB difference in sensitivity between the factory spec for the woofer and the Purezza's corresponding number? Is that from the effect of the enclosure and PR vs. a free air measurement?

Baffle step compensation is also often a part of that.

 

[Bruce Morgen]

Baffle step compensation is also often a part of that.

It looks like Rick is trading off some sensitivity for bass extension -- in free air it looks like the woofer is down 10 dB quite a bit higher than the Purezza's impressive 33 Hz.

 

[Selah Audio]

And another difference would be wider dispersion from the 3-way, correct?

It depends on the drivers but some 3-way designs would have wider dispersion. One way I've done that is with a dome mid and ribbon tweeter or 3/4" dome tweeter.

 

[Rick Sykora]

As it is off topic for this review, I created a new thread for Dennis’s new speaker. It is here:

https://www.audiosciencereview.com/...is-murphy-with-sota-drivers.15893/post-510137

Please make any related new posts there and I will arrange to move the existing ones. Thanks!

 

[Rick Sykora]

Requested off topic posts #80, #81-84, #87,#89-90, #92, #94,#101-104 be moved to this thread https://www.audiosciencereview.com/...is-murphy-with-sota-drivers.15893/post-510137

 

[Selah Audio]

Hmmm, how about a MTM or TMM with the Purifi?

As long as I am blowing the budget, how about Purezza CBT?

Yes, perfect for a CBT.
I do envision more Purifi designs down the road.

 

[Selah Audio]

Will you be designing any Purifi + Bliesma speakers? The Bliesma tweeters look to have really good dispersion for the form factor as well.

I have the 25mm Bliesma beryllium version on hand.

 

[cOz]

Great review and congratulations to Rick. I'm enjoying my Ceramicas all the time but have to admit that these new Purifi Woofers look awesome. Rick, what would the next step up be from this design?

 

[hardisj]

All I know is Rick said he wants these back. But I have been working on my photoshop skills for passports and brushing up on languages native to countries that don't extradite.

 

[Ericglo]

All I know is Rick said he wants these back. But I have been working on my photoshop skills for passports and brushing up on languages native to countries that don't extradite.

I thought youtubers received free swag for heaping lavish praise on products they recommend.

 

[Selah Audio]

Excellent review yet again by Erin! Not to mention the excellent speakers as well.

One question, is that SB Acoustics SB15SFCR-00 passive radiator being used at the back of the speaker? Weird that I only got an F3 of 45Hz modelling in Vituixcad using these driver combos, but I probably did something wrong.

That's the correct passive radiator and your modeling is pretty close to mine. Here's the nearfield I did summing the woofer and passive radiator outputs. This of course looks different than what Erin measured since it doesn't have the baffle step loss included.

 

[Selah Audio]

Would there be any benefits to a DSP cross-over (active) version? Not that I am complaining about the current version, which seems terrific.

DSP is great and certainly applicable to this design. I have a MiniDSP 2x4HD that I may experiment with on the Purezza. The extra EQ gives you flexibility and helps tame any room issues with the bass response.

 

[Selah Audio]

Sorry to ask a naive question, but I assume that this is different from sensitivity? I am guessing that because of the lower distortion, even though it isn't the most sensitive speaker, it can be pushed harder and therefore is potentially louder?

Power handling, sensitivity, and excursion capability are all factors in how loud a speaker can play without excessive distortion and / or compression. You can get higher sensitivity with a 6.5" woofer; however, the cabinet volume increases significantly to maintain similar bass extension. Many woofers will actually have less bass extension because of the tradeoff of box size, sensitivity, and low end response.