Official Premature Arvo Pärt Picante thread

[gainphile]

Smart idea with that wg pressure-mount !!

My pest before with doing this was to keep the tweeters on a right/square angle.

Is this making music yet :T

[JonMarsh]

Just making measurements so far. But at least that was accomplished today, given some glitches with cables and other things which always occur when bringing the gear out of storage AND setting up on a new computer for measurements.



The waveguide performance is not as uniform as I'd hoped for, but for testing the LIO-8 it still should be possible to get a fairly good system response, especially using the averaged response over a +/- 30 degree forward axis. The waveguide performance can probably be improved by milling another set of guides with less material removal- a Thanksgiving weekend project?



The Illuminators looked pretty much as I expected on this baffle, and as the midrange performance looks clean and the distortion stays low to several kilohertz, I'm not expecting problems using them up to about an 1800 Hz crossover. Note that the HF peak is localized to pretty much on axis; go slightly off axis and it drops way down, so there's not that much energy going around in the cone. Still, I'll probably use a notch in that area just to nail it dead. Distortion is quite low up to 2 kHz and not much of a bump at 2400, which subsides again until about 6-7 kHz. Pretty decent behavior for a metal cone driver.



I measured the woofer output nearfield at the mouth of the front to get an idea of what the cavity resonance looks like; about an 8 dB notch at 180 Hz should take care of that, and I think a 120 Hz crossover should be no problem. Famous last words, right?

[JonMarsh]

Playing with the data this morning

Looks like something useful can be done in line with what I expected.

First, the more conventional expectation, looking for flat response from the range of the nominal LF crossover to the top end...



Not too much different from the proposed concept stage last December, other than the starting raw response is fair different! The "mid" driver is the one at the top of the panel; the "LF fill" driver is the one below the tweeter.



Same topology, but voiced for stereo phantom center, per Linkwitz and others.






It seems a good starting point, but lets see what happens after it's wired up! At least I have a starting BOM...

[JonMarsh]

Transfer function

Possibly also of interest, and somewhat indicative of why I didn't plan to do this part active, considering the amount of DSP resources required with sampling rate of 176.4 kHz!

[Johnloudb]

Looking really nice there Jon!!! So this stereo phantom center voicing you mention done by Linkwitz and others (I think you mentioned Maggies in another thread), is there because of the effect of a persons head on percieved loudness at higher frequencies? Is that just from stereo speakers?

So, looks like a gradual attenuation of frequencies above 1kHz.

[JonMarsh]

Linkwitz has a specific recommended curve- a shelving effect down a total of 3.2 dB. I'm not sweating the precise curve until I get measurements with crossover parts and ready to dial it in. Assuming too much in simulation usually leads to playing in the noise floor- GIGO. I'll post a graphic soon with his EQ curves in different versions of the Orion.

[dar47]

Good to see you back at it. The experiment with the voicing is looking promising.
I'm finished with the Modula MK2 rebuild and ready for the Ardent build so don't stop now your doing great work. :W

Here are the new cabs,

[JonMarsh]

Those look great- thanks for the pictures!

As Hank puts it, I have to defend my weekends- still have a big challenge going on, but hope to be able to do that the rest of the year.

I've got to order another set of Illuminator aluminum 7's and hog out the second cabinet (test process on cabinet 1 worked fine for the size adjustment- was a bit tricky in concept). I do really like the Beo tweeters. So much so that I'm pondering going to the next level for the Isis like project. Diamonds aren't just a girl's best friend...

[wkhanna]

...........and ready for the Ardent build so don't stop now your doing great work. :W

Amen on that!
My best friend Dan (PewterTA) could not wait any longer and recently brought home a set of 802Di’s.
My budget is not near so healthy, so in patience I maintain.

[JonMarsh]

Looking really nice there Jon!!! So this stereo phantom center voicing you mention done by Linkwitz and others (I think you mentioned Maggies in another thread), is there because of the effect of a persons head on percieved loudness at higher frequencies? Is that just from stereo speakers?

So, looks like a gradual attenuation of frequencies above 1kHz.

Here's the variety of targets SL tried on and finally settled (with other listeners) as V2 being best. This is from a presentation he gave; I have the PDF and audio file for those interested.

[dar47]

Diamonds aren't just a girl's best friend...

Now your out of my league. ops:

It will be interesting to see if the Illuminator's for the Ardent's are worth it but you got me with the BE tweets. Now the Isis with 10's maybe but if your doing 12's I don't think I can fit them and I still need to come up with a centre.
Geez Jon, lots of great options.

[Johnloudb]

Here's the variety of targets SL tried on and finally settled (with other listeners) as V2 being best. This is from a presentation he gave; I have the PDF and audio file for those interested.

Nice, thanks Jon! Yeah, I would love to see the PDF when you can. Just send via the email in my member profile. Thank you much!

[JonMarsh]

Nice, thanks Jon! Yeah, I would love to see the PDF when you can. Just send via the email in my member profile. Thank you much!

Done.

[JonMarsh]

Always check and re-check

That's the trouble with trying to work on stuff late in the evening after a long work day!

Well, hopefully I'll be able to follow Hank's advise more often in the coming weeks and months and do more of this on the weekends.

The RLC that I'd "blocked out" by raising the R to 2K is gone, and other circuits completely re-checked and updated. Working on a BOM for ordering.

Updated:





Let's hear it for a new Photo-bucket Pro account!

[JonMarsh]

Gf asked me tonight whatever happened to those funny cabinets I was working on in 2011... I said, Mike and the revival of the three way design study happened to them...

They've been sitting in storage since October 2012... Gonna have to do something about that...

I'd actually forgotten how far I'd gotten in the work- maybe around Thanksgiving I should order some crossover parts and break out the Metric Halo LIO-8 and work on the crossover....

[JimS]

Gf asked me tonight whatever happened to those funny cabinets I was working on in 2011... I said, Mike and the revival of the three way design study happened to them...

They've been sitting in storage since October 2012... Gonna have to do something about that...

I'd actually forgotten how far I'd gotten in the work- maybe around Thanksgiving I should order some crossover parts and break out the Metric Halo LIO-8 and work on the crossover....

BUMP, (re)subscribed

Hey Jon - hope all's well, just caught up with the Ardent thread and looks great!! I've had a crazy past year with work and new house build (moving in ~Nov timeframe) which should line up well with your revival of this project. Would be fun if we could put together a similar small group build on this one as well . . .

[JonMarsh]

Hi Jim! Long time no hear from you! Believe me, I understand about crazy years- I'm still in one, though I'm hoping it concludes in a few months!

Well, I did the fabrication drawings for these in EazyDraw (Mac), but it wouldn't be at all difficult to generate full CAD files in Shark. And your interest is certainly adding to my motivation to get back to these. I'll have to come up with a grille concept to keep GF happy, and I'm scratching my head a bit about what to use for amplification- but another pair of nCore 400's might be easy to justify.

Since yesterday I'm also pondering another dipole build, resurrecting a slightly simplified version of the Saint-Saens, depends on what kind of performance I can get out of my RD50's in a Genesis 2.2 Junior style baffle. I have a mess of Fountek ribbon tweeters purchased for that, but I'm considering something more radical at this time- figuring dual 10s on the bottom, have to see how clean the Seas ones from the Arvo Picante are up a bit higher, or I just might use the Aurasound 10's I've got. The bottom will likely be sealed force canceling setup, with dedicated nCore 400 modules and EQ; they will have to run up to ~180 to 250 Hz, I figure.