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Old 2nd May 2007, 06:40 PM   #631
dmason is offline dmason  United States
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There is little doubt in my mind that John and Charlie at TT would entertain a group buy, to help get out the word. They are grateful to have had it pointed out to THEM, that this stuff needed to be more widely exploited...

Anyone have a look at the spex file for the 8 inch? Might be The condo-sized wideband OB driver...
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Old 2nd May 2007, 07:03 PM   #632
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Can you please post a link? Thanks. James
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Old 2nd May 2007, 07:54 PM   #633
dmason is offline dmason  United States
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www.tonetubby.com

www.abrown.com --->Sales

one and the same. They also have hempcones for retrofit into certain JBL bass units. 2115 is one, I believe.
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Old 2nd May 2007, 09:54 PM   #634
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Quote:
Originally posted by SunRa
That TT 12" alnico sure feels nice and measures well but that basket looks quite weird for a 200+ $. I guess the effects (like difractions) are more obvious in OB than in a stuffed and dampend monopole. I wonder if in case of a group buy they would make a custom basket more like in the 18sound style (see 15nd930, as someone here said, I guess a more opened basket than that you can't have.... well maybe the phy-hp ones)...
I'm sure that TT buys their baskets, voice coils, magnets, surrounds, spiders, dust caps, cones, and glues from other vendors. What they do is final assembly, not that different than their original re-coning business.

If we do a group buy of the 12" Alnico model, one of us working with one of the TT staff could track down a prosound-style low-resistance basket that would be mechanically compatible with the Alnico magnet and the existing spider assembly. I'd vote for a gloss-black paint job, instead of the gloss-red TT uses for the guitar speaker (gloss-black drivers would look sharp on a gloss-white dipole baffle).

The 12" Alnico TT is available in three cones: the original undipped one, the dipped one, and a double-dipped one. The standard cone has a single dipping at the center. I suspect the dipping process is more like a stiff lacquer, and extends and strengthens the HF response (at least according to the comments on the TT site).

Gary Pimm tells me the little dip in the middle of TT response is the same thing he saw on the stamped-metal Beta8's he uses, and it takes a thick layer of felt glued to the frame to remove it.

So - if the 12" TT has a low-resistance frame, we'll see a single broad peak centered around 3~4 kHz. The dipping process is probably what creates that peak in the first place, letting the center of the cone "take off" at those frequencies. That's my guess, anyway, in the absence of measurements of the three cones. The undipped cone may be the smoothest, although that's strictly a guess.

Before we do any group buys, somebody (not me, I'm not able yet to do this) needs to measure ALL THREE cones on a LARGE baffle (at least the IEC-standard of 85 by 115 cm) with a MLS measuring system. No Radio Shack hand-plotted warble-tone measurements, please.

Quote:
Originally posted by jeff mai
Lynn,

I think it's wise to stick to a path you know is likely to have a result you like. If you hear a pair of fantastic horns later on and you feel you're missing out you can do something about it later. Tracey and I may even end up back in Ft Collins in the next couple of years - you can come over and hear my horns!

I am curious to hear what music you use to audition speakers for particular problems. If you have a chance to list a few things that I would appreciate it. Although it isn't a lot of value to get second hand evaluations, if I could track down some of the pieces I would report back what I hear.

We do share a taste for BBC speakers. I've had 4 different pairs, including Spendor SP1/2s that are sitting idle on a shelf at the moment. I think it is a good sign that since I got the EQ dialled in on these horns I have not given the Spendors a single thought!

Jeff
Hi Jeff, you're posting in the other forum that your Azurahorns have a very small sweet spot, no more than one listening position wide. This was my experience with the Lowther/Azurahorns as well, but I had ascribed the extreme directivity to the use of a wide throat and a whizzer-cone driver. Hearing the same thing happens with a totally different 2" compression driver gives me pause on the whole horn thing, frankly.

Part of the reason I say that is the Azurahorn is sonically the best horn I've ever heard - and I was willing to overlook the extreme directivity, thinking it was just another Lowther artifact. The emission from a Lowther is hardly a plane wave, after all, and my understanding is that horns basically convert ideal plane waves to spherical waves by the time they leave the horn. When the wave entering the horn is non-planar to start with, passage through the horn makes it much worse - it doesn't magically "straighten-out" a rough wavefront, it scrambles it more.

What I hear with the Lowther/Azurahorn right outside the one-foot-wide sweet spot isn't a tonal abberation, but a dramatic loss of coherence, and collapse of width and depth. It's still listenable, in fact better than most old-school PA horns, but the tonal vividness and 3D quality disappears. I surmise this is due to an incoherent wavefront outside the sweet spot.

If this is true for 2" compression drivers as well, it puts the 90-degree dispersion claim in a completely different light. Yes, there's "sound" within that 90-degree cone, but if the good sound beamwidth is no more than 3~5 degrees wide, that's not good news. I don't need a four-foot-tall headphone.

Regarding the other candidates for the HF driver, well, if the Fountek is a metallized-plastic multi-layer diaphragm, that removes it from contention. Sounds like the other ribbon drivers are a better choice. Too bad the larger Mundorf AMT's have prices that are equivalent to an ounce of gold per driver - with the US dollar dropping week by week, this is kind of expensive for American buyers.

As for music, eh, no special choices, although I do listen to large-scale symphonic music and heavily-cooked rock-n-roll, like Pink Floyd, Alan Parsons, and Sarah McLachlan. Basically no jazz at all, but I like black choral Gospel music - I heard this in Memphis at a Sunday church service, and man, is it good! Like really good barbecue cooking, it's common in the South, and rare elsewhere in the USA. (My daughter-in-law and grandkids live in Memphis, and we visit occasionally.)
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Old 2nd May 2007, 10:20 PM   #635
ScottG is offline ScottG  United States
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Quote:
Originally posted by Lynn Olson


I don't need a four-foot-tall headphone.


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Old 2nd May 2007, 10:48 PM   #636
Cappy is offline Cappy  United States
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Quote:
Originally posted by Lynn Olson

What I hear with the Lowther/Azurahorn right outside the one-foot-wide sweet spot isn't a tonal abberation, but a dramatic loss of coherence, and collapse of width and depth. It's still listenable, in fact better than most old-school PA horns, but the tonal vividness and 3D quality disappears. I surmise this is due to an incoherent wavefront outside the sweet spot.

If this is true for 2" compression drivers as well, it puts the 90-degree dispersion claim in a completely different light. Yes, there's "sound" within that 90-degree cone, but if the good sound beamwidth is no more than 3~5 degrees wide, that's not good news. I don't need a four-foot-tall headphone.
I had the BD-Design Oris 200 Horns with AER MD3 drivers for about three years and while I enjoyed them a lot the "headphone" effect you mention was one of my biggest complaints. The whole tonal balance degraded dramatically outside of the heaphone zone too. I think the Oris/AERs probably have a lot in common with the Azurahorn/Lowthers.

My current speakers are Bert's latest Orpheans which are modified 2" BMS 4592ND compression drivers in a "250" horn, which has a different flare.

Now these really have a lot better dispersion. I can walk around my room and get a good stereo image from a lot of places. The tonal balance is also quite even around the room.

These are still horns, however. They have a lot of "freedom of sound", they have other charms, but in this parameter, they still can't compare to good open baffles, with their really great openness.

The best sound is probably in a 45 degree window. It is a lot better than 4 degrees, but it isn't 90 degrees either.

So I think it is correct to be cautious in mating a horn for the upper range to your OB drivers. There is an excellent chance it won't work.

On the other hand, I think a good 2" compression driver is still worth considering. Since the midrange driver will be carrying a lot more weight, who knows, it might work. My tonal balance is good outside the 45 degree window, but the 3d image flattens out. An important key, it seems to me, is whether you can find a horn with a copasetic, high dispersion flare. But if you need 90 degrees, well, maybe not.
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Old 2nd May 2007, 11:07 PM   #637
Variac is offline Variac  United States
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Here's an interesting TT page I hadn't seen before.

http://www.tonetubby.com/pr.htm

Towards the bottom they announce their entry into PA and home speaker markets.

I will try to get up and talk to them someday soon. Maybe they'll get me some "loaners" to measure and listen to as long as we return them .
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Old 2nd May 2007, 11:43 PM   #638
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Quote:
Originally posted by Lynn Olson
Hearing the same thing happens with a totally different 2" compression driver gives me pause on the whole horn thing, frankly.
At least part of this is due to the extreme geometry required for a 204Hz mouth size and length with a 1.4" throat. A smaller, shorter horn would be much better in this respect. So would more listening distance, but that's not going to happen with Australian property prices!

Basically, if you can't see the phase plug from where you're listening, the high frequencies aren't going to get to you. This is true of all horns that I know of that have no vanes or cells or diffraction geometries all of which introduce another set of problems.

Anyway, this is why I suggested avoiding horns (in the midrange anyway) until you hear one you can live with. I really like what mine do on axis. I wish they were better off axis, but what can you do?

Maybe a constant directivity horn - I was going to build a large conical before deciding to buy these Azurahorns. Have you heard the Cogent system with their conical horns?
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Old 2nd May 2007, 11:57 PM   #639
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Quote:
Originally posted by Cappy


I had the BD-Design Oris 200 Horns with AER MD3 drivers for about three years and while I enjoyed them a lot the "headphone" effect you mention was one of my biggest complaints. The whole tonal balance degraded dramatically outside of the heaphone zone too. I think the Oris/AERs probably have a lot in common with the Azurahorn/Lowthers.

My current speakers are Bert's latest Orpheans which are modified 2" BMS 4592ND compression drivers in a "250" horn, which has a different flare.

Now these really have a lot better dispersion. I can walk around my room and get a good stereo image from a lot of places. The tonal balance is also quite even around the room.

These are still horns, however. They have a lot of "freedom of sound", they have other charms, but in this parameter, they still can't compare to good open baffles, with their really great openness.

The best sound is probably in a 45 degree window. It is a lot better than 4 degrees, but it isn't 90 degrees either.

So I think it is correct to be cautious in mating a horn for the upper range to your OB drivers. There is an excellent chance it won't work.

On the other hand, I think a good 2" compression driver is still worth considering. Since the midrange driver will be carrying a lot more weight, who knows, it might work. My tonal balance is good outside the 45 degree window, but the 3d image flattens out. An important key, it seems to me, is whether you can find a horn with a copasetic, high dispersion flare. But if you need 90 degrees, well, maybe not.
Thanks, Cappy, you are the first person to chime in about the difference between the large-format Oris/Azurahorns and the 2" compression-driver versions. As we know, BMS compression drivers are right up in there in quality, so your comparison is very much appreciated.

This "close-focus" effect is something I've never liked about horns. It's entirely separate from tonal colorations and CD grit-n-grain; this is what seems to remain when those grosser old-school problems are successfully resolved.

A lot of horn enthusiasts, particularly jazz fans, love the sensation of the musicians playing right in your lap. If all you listen to is jazz, OK, I get it, it has that sitting-next-to-piano jazz-club ambiance. It works for small-scale chamber music too, if you like to sit two feet from the harpsichord.

But - this presentation ruins large-scale choral music, whether church gospel with a rockin' Hammond B3, Beethoven, or Carmina Burana, and it throws off the scale of big-scale electronica as well, where a lot of effects rely on 3D near-far spatial impressions (side two, Dark Side of the Moon).

What's interesting is that large-diaphragm dipole midranges sound big, as you'd expect, but there's none of that close-focus effect. They just sound big and open, like a big electrostat, but with relaxed-n-easy dynamics, instead of that nervous getting-too-close-to-overload electrostat sound.

So what's the best match for HF?
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Old 3rd May 2007, 12:08 AM   #640
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Quote:
Originally posted by jeff mai

Maybe a constant directivity horn - I was going to build a large conical before deciding to buy these Azurahorns. Have you heard the Cogent system with their conical horns?
Yes, at the last RMAF. Listening window barely one seat wide - much less than the Azurahorn, with quite noticeable off-axis tonal shifts. I hope I don't offend Steve Schell, but I can't see any difference between a conical horn and a plain old megaphone. I wanted to hear the field-coil drivers on a different profile horn, something with more air to the sound.

The Azurahorn/Lowther loses focus and part of its 3D quality outside a 12~15" window, but there aren't any tonal shifts. I imagine your experience with the Oris and Azura horns with 2" compression drivers is similar.

At this point I wonder if the reasonably small 18Sound 80 x 60 elliptical (OS) horns would offer more spacious sound - just so long as the crossover was reasonably steep and the CD was not allowed anywhere near the cutoff region.
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