Selah Audio Purezza Review

[bunkbail]

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.

 

[Selah Audio]

@Selah Audio, that BZ Labs CQ76B tweeter looks interesting.

Can you comment on why you chose this ribbon tweeter? When I search on it, I find very little info, and mostly mentions from you in your own designs!

I’d be curious to hear how you heard about it and your thought process in using it with some of your designs.

I've always liked ribbon tweeters and I think I noticed a test that Vance Dickason had in Voice Coil. I started using the BZ tweeters six years ago. It's actually kind of a ribbon/planar hybrid. The CQ76B in the Purezza can cross low and I thought it would be a good match for the Purifi woofer.

 

[Dennis Murphy]

Here's a link for a Klippel test of the Scan-Speak woofer used in the Philharmonic BMR (kit and older assembled speakers). As far as how the bass extension compares to the Purifi used in the Purezza you can look at Erin's curves. Keep in mind that the cabinet volume for the Purezza is also at least 30% smaller which makes the comparison even more interesting.

I used the previous version of the Scan-Speak several years ago. In the 90's it was considered to be one of the best 7" woofers. If you read the review you'll note that the suspension limiting is 2.8 mm, far short of the 6.5 mm x-max (excursion). Erin can sort out the other differences from the Klippel test he did on the Purifi.

https://www.pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/40_Voice_Coil/2012/2012_8_Aug.pdf

To be clear, I never tried the Purifi in a .5 cu ft cabinet with the SB Acoustics PR. I tried various cabinet volumes with a regular port, and that just didn't work out from a port length or port noise standpoint. What I tried last was the Purifi in the BMR cabinet with two opposing side-mounted Purifi PR.s (Ka Ching). Even without added weight, the PR's tuned the box too low. I was running out of time and money at that point and I wanted to keep the cost of the BMR down and chose to go with the SB ceramic woofer. I concluded that the Purifi really was meant for 2-way applications in a smaller box. As for the Scan, my eyes aren't what they used to be 100 years ago, but I didn't see the reference to the 2.8 mm suspension limiting, and I'm not sure what the practical implications of that are, or how it could even be true given the woofer's power handling. All I saw was that Vance was able to achieve 110 dB before the cone excursion exceeded its linear travel. As I mentioned, I'll get a chance to work with the Purifi again soon in a 2-way MMT design.

 

[yourmando]

I've always liked ribbon tweeters and I think I noticed a test that Vance Dickason had in Voice Coil. I started using the BZ tweeters six years ago. It's actually kind of a ribbon/planar hybrid. The CQ76B in the Purezza can cross low and I thought it would be a good match for the Purifi woofer.

Makes sense. Yes, I found the the 2 Voice Coil reviews in my search. Pretty much the only other mention of this ribbon/planar than your website. Looks like you're on the frontier with this tweeter. I thought it was interesting that Vance said the directivity was similar to 1" dome tweeters, horizontally.

Pretty amazing how seamless the directivity match is at your chosen crossover point and narrow width. I would have thought the 6.5" would be beaming too much by 2.4khz, but apparently not! That tweeter can crossover down to 1kHz, but clearly better crossed up higher.

I've always wanted to design my own DIY, but talk myself out if it every time. I could rapidly iterate on testing crossovers digitally, but it seems the hard part is finding whether 2 drivers can combine with smooth directivity in the cabinet/baffle config, especially in a 2 way. That fact that this is possible without a waveguide is pretty cool.

 

[Ilkless]

I've always liked ribbon tweeters and I think I noticed a test that Vance Dickason had in Voice Coil. I started using the BZ tweeters six years ago. It's actually kind of a ribbon/planar hybrid. The CQ76B in the Purezza can cross low and I thought it would be a good match for the Purifi woofer.

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

 

[snackiac]

Hopefully on topic enough, but would be possible to make an on-wall capable version of this like the Revel S16 vs the M16?

 

[Selah Audio]

Hopefully on topic enough, but would be possible to make an on-wall capable version of this like the Revel S16 vs the M16?

Yes, but the vertical dispersion is more narrow due to the ribbon. Ideally you would want the cabinet angled downward and modified for placing the passive radiator on the front. It's also possible to design it with a smaller sealed box with a higher -3dB point for bass extension.

 

[snackiac]

Yes, but the vertical dispersion is more narrow due to the ribbon. Ideally you would want the cabinet angled downward and modified for placing the passive radiator on the front. It's also possible to design it with a smaller sealed box with a higher -3dB point for bass extension.

Very cool! I figured the radiator would have to go just like the S16 gets rid of the port. I like the S16 form factor but do not like the appearance, so I'm thinking possible DIY, but I'm brand new to it. These look awesome and I might give em a go.

 

[MZKM]

Personally, I don't put any stock in the scores. That's why I don't calculate them. But if you want, I have attached a link to both the original and the EQ'd versions
https://www.dropbox.com/s/0d1shxs7z0nv39m/Selah Audio Purezza.7z?dl=0

Ok, I think I got it, it is like 42PPO, so I left it, and I just did the EQ'd version:

Preference Rating
SCORE: 6.6
SCORE w/ sub: 8.3

This would put it near the top of my list, ranking above the KEF R3 for both scores.

 

[digitalfrost]

 

[Ericglo]

Ok, I think I got it, it is like 42PPO, so I left it, and I just did the EQ'd version:

Preference Rating
SCORE: 6.6
SCORE w/ sub: 8.3

This would put it near the top of my list, ranking above the KEF R3 for both scores.

The $6000 Genelec is the only speaker that outranks it without a sub and the Genelecs and Neumann with a sub. It is also the highest rated passive speaker.

That along with the recent highly rated Integrity should firmly establish Ricks ability as a world class speaker designer.

I don't see a score on the Philharmonic BMRs, bu the AAMs have a good score. I think we are seeing the talent that Rick, Dennis and some others in this market truly have.

 

[Poseidons Voice]

Since Erin also measured the BMR, we should be able to get a preference rating there as well.
When looking at the polar plots, the BMR is a bit smoother and the early directivity index transitions are very smooth as well. However, I don’t think those metrics can be used at this level of comparison.

What starts separating the two contenders is freedom from dynamic compression. Erin’s measurement and confirmation that the Purezza sounds cleaner when played louder is key. It will definitely make the speaker sound more “real.”

Both are excellent well designed passive speakers so bravo!

Best,
Anand.

 

[MZKM]

Since Erin also measured the BMR, we should be able to get a preference rating there as well.
When looking at the polar plots, the BMR is a bit smoother and the early directivity index transitions are very smooth as well. However, I don’t think those metrics can be used at this level of comparison.

What starts separating the two contenders is freedom from dynamic compression. Erin’s measurement and confirmation that the Purezza sounds cleaner when played louder is key. It will definitely make the speaker sound more “real.”

Both are excellent well designed passive speakers so bravo!

Best,
Anand.

Pierre calculated it (I didn't, as Erin's data files are separate for each angle and includes phase info, so they all need to be combined, modified, and correctly ordered; it was a pain just to do this one). I think the BMR doesn't score as high. Selah has 3 bookshelves more expensive than this one, I wonder how they compare.

 

[samysound]

I wonder how the purezza compares to the Revel M126Be. Pricing is not too far off if compared to the "street" price of the revel.

 

[Selah Audio]

I wonder why the Purifi passive radiator wasn't used, what changes would be required to use it, and it's effect on the speakers' bass performance. The look of that funky surround on the Purifi woofer is growing on me.

Martin

A few different reasons. When I started planning for the design the passive radiators were not readily available here in the USA. I modeled the bass response with the Purifi passive radiators as well as the one here (SB Acoustics) and a few others. For simplicity and cost I felt that this was the best way to go. Using the Purifi units requires two of them per cabinet and this changes the look as well as the overall cost. The main advantage is greater output capability; however, as you can see from the tests the Purezza doesn't lack in that area. I decided that unless someone wanted to drive them at extreme levels beyond the norm the chosen design would be more than enough. I certainly could do a double-PR version if requested.

 

[Selah Audio]

Looks like kits do not include cabinet flat packs, but he can provide a quote:

View attachment 81891

I've added information for unfinished MDF cabinets. http://www.selahaudio.com/purezza-kit

 

[HooStat]

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

 

[Ericglo]

I've added information for unfinished MDF cabinets. http://www.selahaudio.com/purezza-kit

 

[Chromatischism]

Not trying to hijack the thread, but just to let you know, the tweeter I'll be working with on the Purifi MMT should be of interest to speaker junkies. It incorporates a lot of new technology and I don't think anyone else is using it yet. It can be crossed at 1200 Hz with 180 degrees radiation. Here's a link to an AudioXpress article about it: https://audioxpress.com/news/the-airblade-transducer

I remember reading about this a couple of years ago but like you say, not much talk about it and I started to wonder if it was vaporware.

 

[yourmando]

Me trying to justify a purchase