The new Dayton 8" may be the value solution for a line array, but...

[Hank]

this new Adire 6" may be the ne plus ultra premium puppy: http://www.adireaudio.com/TextPages/...eFrameText.htm
13mm one-way Xmax, and LOOK at the lower and upper extension :E This could be crossed over to an RD50 high enough to keep all mid/upper base freqs out of the ribbon.
With that Xmax, maybe 5 per side would be sufficient - maybe 4?

[JonMarsh]

Hiya Hank!

Back from another week on the road...

The driver construction is quite interesting, especially the small motor assembly and minimal rear shadow to the cone... the FR is promising, but the Impedance curve shows a strange discontinuity starting at 500 Hz and ending at 1 kHz. Measurement artefact? Surround vibration? (They're using doping on the inner edge of the surround) Cone mode? Hard to say, without doing some true "nearfield" work, i.e., 1 inch distant scans at cone center, edge, and mid between. Regardless of the claims for usable response to 3 kHz, I'd still be inclined to keep the crossover no higher than 600 Hz or so, unless I can really see a good explanation for the published "glitches".



For a "conventional" cone six, the best I've seen so far (for cone behavior) is the Peerless HDS without the phase plug. But they don't have the Xmax or right Qts for dipole, either.

The inductive rise is low, but that just means they're using more current to keep the drive level up and get the upper end response. I'm surprised that the relatively small surround supports a 13 mm Xmax, but then maybe this is more like a 7" driver than a six- didn't see published dimensions.

I think it's time to do some "back of the napkin" calculations re directivity, swept area, etc, for some of these possible solutions.

4 TC2+
6 Dayton 8"
8 Extremis 6"

Thinking in terms of directivity, the TC2+ will be just as good at 600 Hz as the M8a are at 1200 Hz (re radiating diaphragm size versus wavelength), so the 12's aren't ruled out there. Dispersion beyond that is pointless, given the dipole cancellation. And the M8a's hold up to 60 degrees off axis at 1200 Hz.


The six's would probably allow a much tidier baffle design, but I'm pretty sure, even with the long Xmax, they aren't going to move as much aire- but maybe enough?

Normally I wouldn't consider a 6" for dipole, due to swept volume limitations, but with this Xmax, it may bet by that. Plus, I really do like the small motor shadow for a dipole.

Hmmmmmmm. I'm still thinking 8 of these might be nice for a dipole line array. But it's a risky pre-order bet to save $20 per driver; the deal on the DPL12's was a little bit sweeter....

Qts is pretty ideal for a ported box, but not in the right range for sealed or dipole.

After I get some of my "napkin" calculations done, including price, I'll report back...

~Jon

[ThomasW]

but the Impedance curve shows a strange discontinuity starting at 500 Hz and ending at 1 kHz. Measurement artefact? Surround vibration?

I ask Dan Wiggins about this, his reply was......

The bend at ~600 Hz shows the starting impact of the copper in the motor. It's not a glitch, but a transition in the impedance from the start of the inductance reduction of the copper on the pole.
The glitch at 1 kHz is a slight reflection off the spider/basket - can't get that one any smaller. It's pretty minimal though, and doesn't show up in the frequency response really.

[Mark K]

Hi Guys,

I'd be happy to look at this driver and see if it performs well compared with the Dayton, other, more conventional 8"s, and maybe even a good quality 10", like the L26. I may buy one, but really, at this point I'm tired of buying stuff that I'll probably never get to.

Anyone want to preorder and send it to me???

PS Sorry we missed you at the NC DIY last Saturday. I was going to give you the hales tweeters!

My speaker pages

[Mark K]

Jeez, still a junior member...so humiliating...

[JonMarsh]

Hi Mark,

You're pretty senior in my eyes, you've done some great driver measurements this year!

But don't be in any hurry to grow up- the Senior citizen discount isn't all it's cracked up to be....


Well, your post here is very timely, because I was planing on emailing you today to ask if you'd measure one of these if I bought some...

The sixty four dollar question is, should I buy more than a few? Lord only knows I can do SOME kind of design with it.... (imagine a ported MTM with a Millenium Excel tweeter crossed over about 1500 Hz?)

So, I'll check my piggy bank this weekend and make a decision about how many to order... and I'll send one to you as soon as I get it. I should have your address somewhere around here; if not, I'll contact you for an update.

I missed being at the DIY- my only excuse is work- this month has been a bear. I was on the road all last week, too, and will be again next week. This weekend I think I'm going to be able to avoid going into the office, but I will have to be late on one item to avoid a trip- it's only my year end review. Spent all morning on work email, still have a few more things to get out of the way.

It's hard to have much of a personal life under these conditions- my boss is getting an earful when he conducts the review, and a written, documented statement of my issues (including covering a lot for other people, who never cover for me).


Best regards,

Jon

[Mark K]

If you want to order one and send it to me, just let me know. I can throw in the Hales when I send the driver back to you.

I think this driver could be pretty nifty in some situations, especially something like a ported or ML TQWT-since those seem to model best with larger Sd's (So a smaller, long throw woofer makes for a slimmer cabinet!!!)

I'd be curious to see if this driver really can perform like an 8" or 10". As impressed as I am with what I've heard of Adire's motor technology, it remains to be seen if the entire motor and cone can have good higher order linearity at high excursions.

[JonMarsh]

I've been considering a "build" of MT's even, using one of the PE cabinets, for surround, so worse comes to worse, they'll be usable there.

But I really like the small motor and minimal rear "shadow"- my gut feeling says these could be pretty cool, and would certainly be lighter than some of the alternative drivers I've been considering to pair with the RD50's. It would make for a narrower, lighter main panel- perhaps combine it with a W dipole below 100 Hz, or maybe just an H or U baffle woofer with TC2+.

I'll let you know when they get in, and send you one.

~Jon

[JonMarsh]

Ordered last night.

~Jon

[Hank]

But I really like the small motor and minimal rear "shadow"- my gut feeling says these could be pretty cool

It would make for a narrower, lighter main panel-

Yep, those thoughts came to mind when I read about the driver. The side view reminds me of a small TB with a very small neodymium motor. Let us know how they really sound.

[JonMarsh]

Yup, they should be interesting. I'm going to try doing a small ported box, too, like the EM-72 I did for my duaghter last year with a relatively high excursion HiVi D6, a Dynaudio "clone". But these will have about double the Xmax.

I'm very interested in seeing unsmoothed MLS plots a 1" at center, edge, and mid to edge. Mark K will do liner and non linear distortion measurements.

Oh, you think we should LISTEN to them, too?!?

Heck, I don't even just "listen" to cables- maybe I should try that someday, to save time! But then, I always have like Stereophile better than the Absolute Sound, because John Atkinson DOES measure as well as listen.

~Jon