Lynn,
How have you gotten derailed from your original plan of a full range hemp cone driver augmented by a true tweeter and woofer? I'm somewhat to blame for the sidetrack, but as much as I like horns I think this is a better idea than crossing to a horn at 1-2khz. Just my opinion, of course!
Jeff
How have you gotten derailed from your original plan of a full range hemp cone driver augmented by a true tweeter and woofer? I'm somewhat to blame for the sidetrack, but as much as I like horns I think this is a better idea than crossing to a horn at 1-2khz. Just my opinion, of course!
Jeff
jeff mai said:
Well, Jeff, you must have been reading my mind. I was just ambling through the web, and came up with this combo: the Tone Tubby 12" Alnico, with the Fountek NeoPro 5i, augmented with the 15" driver of your choice (maybe the Tone Tubby 15" driver) in a short open-ended box filled with recycled cotton. The 12" wideband driver and the ribbon tweeter would be on an asymmetric open baffle, similar to the shapes shown before, with the tweeter 40" high off the floor.
Crossover is simplicity itself: an acoustic 12 dB/octave crossover between 2~2.5 kHz, depending on how the drivers want to be crossed over (you come in a bit early on the TT, probably 1.5~1.8 kHz, to offset the steep rise at 2 kHz). The net result would be an acoustic crossover where the TT curve flattens out again, in the vicinity of 2.2~2.5 kHz.
The ribbon tweeter would be quite happy with a 2.2~2.5 kHz 12 dB/octave electrical crossover. I might steepen the tweeter HP slope (to 18 or 24 dB/octave) to assure an in-phase relationship between the widerange driver and the ribbon tweeter. This can be confirmed by temporarily reversing the phase of the tweeter and looking for a null - I usually try for a 20 dB null at the acoustic crossover frequency. The larger, floor-mounted bass driver comes in around 200 Hz or so, and augments the 12" driver to offset its 1/f dipole loss.
After careful crossover adjustment, the net response should fall in a +/-3 dB window, and be adjusted to taste. I usually aim for a 1~2 dB tilt from 100 Hz to 10 kHz, with a slight bass emphasis. Net response of the system, depending on size and filling in the bass module, would be from 70~80 Hz to 30 kHz, with efficiency set by the 12" TT, around 98 dB/metre.
Nice alternative to the US$20,000 Verity discussed elsewhere, eh?
Attachments
This latest seems more in keeping with your original ideas, and a lot easier for others to replicate. Probably a lot cheaper too, and based on a topic that is on the minds of lot's of people.
-I think you have about three good systems in mind and you should probably do them all
, but I vote for something similar to this one first!
-I think you have about three good systems in mind and you should probably do them all
, but I vote for something similar to this one first!Since I have two of those drivers at home I will try it out night (except for the 15"TT).
Currently I have the 12" TT Alnico crossed at approx 1.5K/12db and the Neo Pro 5i coming in about 3.5K at 18db. Another 12"TT (temporarily until i place my order for the 15" TT ) for the bass.
I tried the NeoPro5i at 12db but didn't like it (loss of sparkle) – but then I may have done something wrong (interaction with the TT).
On the other channel I'm running the ME2's (separate volume control) to compare.
Don't have any measuring equipment..
Frank.
Currently I have the 12" TT Alnico crossed at approx 1.5K/12db and the Neo Pro 5i coming in about 3.5K at 18db. Another 12"TT (temporarily until i place my order for the 15" TT ) for the bass.
I tried the NeoPro5i at 12db but didn't like it (loss of sparkle) – but then I may have done something wrong (interaction with the TT).
On the other channel I'm running the ME2's (separate volume control) to compare.
Don't have any measuring equipment..
Frank.
Lynn,
Im wondering if you feel you have identified to any extent the design aspects of the Bastani Apollo which were responsible for your revelatory experience with them.
Specifically, I'm wondering to what extent the Apollo magic relied on a high crossover frequency to the tweeter (or complete lack of crossover within its natural passband) and whether, by straying into lower crossover frequencies in a non-coaxial configuration this advantage is being threatened.
Im wondering if you feel you have identified to any extent the design aspects of the Bastani Apollo which were responsible for your revelatory experience with them.
Specifically, I'm wondering to what extent the Apollo magic relied on a high crossover frequency to the tweeter (or complete lack of crossover within its natural passband) and whether, by straying into lower crossover frequencies in a non-coaxial configuration this advantage is being threatened.
Lynn Olson said:
The Neo5 is rather like a wide horizontal dispersion narrow vertical dispersion BMS driver.. clean, detailed.. but lacking when compared to other true ribbons (..rather like a planar in fact, but with better vertical dispersion).
The Aurum Cantus G1 (though measuring poorly by comparison), sounds more natural with its non-reinforced ribbon.
Frankly what you R E A L L Y want is not a std. production unit.. This is the Co. you should contact for that perfect custom "fit" and a base technology that surpasses the rest (audibly and measurably):
http://www.raalribbon.com/products.htm
..still, its too bad DDS doesn't seem to be in standard "business" anymore. I could have directed you to a VERY nice horn that would have provided the correct polar patterns.
Russell Dawkins said:
Well, I really liked the Apollo, but the Prometheus isn't for me. The widerange drivers are different: A is apparently a heavily treated European equivalent to the Celestion Blue guitar speaker, while the P is a somewhat-less-treated Eminence. I should also mention that I found both the A and P horn treble to be OK, but not great, and felt the same about the self-powered monopole subwoofer.
Long story short, the Apollo widerange driver has very special qualities - similar in important ways to the TT hempcone. By contrast, the Eminence has a much cruder, more "shouty" sound, and not to my taste.
It is a very good question how much "air" and dimensionality would be lost by crossing over to something as directional as a horn. My instincts tell me the Heil AMT would be the best sonic and dynamic match to the qualities of the big, powerful widerange driver. Unfortunately, the US-made AMT's have astoundingly bad quality control (6 dB sample-to-sample variation), and the Mundorf's are mighty expensive.
The most memorable qualities of the all-up top-of-the-line Linkwitz and Bastani systems are the stunning dynamics, freedom from boxy sound, and electrostat-like air and spatiality. MBL's get close, but the gross inefficiency means you lose the microdetails and vivid tone colors that come so easily in the Linkwitz and Bastani systems.
So part of the secret is efficiency, low IM distortion, and obviously no box coloration. Electrostats have no box coloration, low distortion too, somewhat more muted tone colors, but the dynamics are not even close. I don't like magnetic-planars at all, finding them opaque and lifeless sounding (very dim tone colors). I surmise high IM distortion due to nonuniform driving force over the diaphragm and a very low BL factor.
The reason I part company with the polar-response brigade is that I'm much more tolerant of blurriness in the mid driver working at the top of its range than I am tolerant of tweeter distortion at the bottom of its range. The HF distortion I find very unnatural and unmusical, gritty and harsh sounding, regrardless of the HF technology - horn, direct-radiator, etc.
Can an Azurahorn with the best compression driver sound as airy, open, and 3D as the best electrostat? I'm not sure of this. What about ribbons? They vary a lot, depending on build quality, and require serious thought about the crossover, since they are so intolerant of excess excursion.
This is uncharted territory for me, and I suspect for others as well. I don't think the answer is as simple as choice of crossover frequencies - it has to do with the inherent sonic character of the drivers themselves, and how well the sonic palettes of each technology blend together.
The greatest virtue of the large-area vintage-design guitar and state-of-the-art professional drivers are effortless dynamics and reach-out-and-touch-it realism, qualities that just aren't there in audiophile speakers. The challenge, which will probably take a lot of listening, is to find matching treble elements. I have seriously thought about small-area electrostats driving a large-throat Oris or Azurahorn.
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)...
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
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
I think Lynnn REALLY wants a pair of TT's and what we have turned up in this discussion only reinforces that they could be a very good choice. Certainly it's essential that he check them out. The stamped steel basket is what guitar players like to see, so I suspect that's why it has them. If Lynn comes up with something great using them, and we order 50-100, I would suspect that we could get a custom DIY Audio version that has a cast basket and maybe a good price besides. It probably only requires them to spec this basket to their driver assembly guys who probabbly have them on hand BUT the unknown is the Alnico magnet- that might only work with the stamped basket, after all probably 99 percent of Alnico ordered is for guitar speakers. Their web site mentions that they are developing a neo magnet version. That might be a good option- Have to wait and see? Here's their Discussion forum:
http://www.online-discussion.com/ToneTubby/
More good stuff. They have a "dipped" version that goes higher.. hmmm
http://www.tonetubby.com/faq.htm
Scott is right I believe about the ribbons. The Founteks are now a aluminum/plastic film laminate, which appears to be much more durable and possibly better damped , but lose some livelyness. It is essential to not cross the ribbons too low, but with the TT that should be no problem..
After my experience with The Aurum Cantus, I would recommend these which are on sale:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=276-410
They have the G1 also of course.
I have had no problems with reliability.
If they prove to be a good match to the TT tone, and in other ways, then Lynn could create an evolved version with RAAL ribbons, which are no doubt an upgrade.
My experience with a wide range open baffle mid has worked well for me and I recommend it.. There is a lot of appeal in having no crossovers in the critical range. I still think an open baffle might be the first thing to try- you can pick up a pair of solid core doors at a construction supply place with pretty veneer for less than $100 each, or get used ones for almost nothing... slap in the TT's and ribbons, and start experimenting.
To create dipole treble, you could use more of the same tweeter faced to the rear....or use something like the AC 2si at $60? Would it still be crossed over high enough to not be overstressed? Being about 3db less efficient, has about exactly the right output, without any padding.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=276-400
The TT, Brown Soun headquarters are about 20 min. from my house, I should get on the bike and head that way sometime.
http://www.online-discussion.com/ToneTubby/
More good stuff. They have a "dipped" version that goes higher.. hmmm
http://www.tonetubby.com/faq.htm
Scott is right I believe about the ribbons. The Founteks are now a aluminum/plastic film laminate, which appears to be much more durable and possibly better damped , but lose some livelyness. It is essential to not cross the ribbons too low, but with the TT that should be no problem..
After my experience with The Aurum Cantus, I would recommend these which are on sale:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=276-410
They have the G1 also of course.
I have had no problems with reliability.
If they prove to be a good match to the TT tone, and in other ways, then Lynn could create an evolved version with RAAL ribbons, which are no doubt an upgrade.
My experience with a wide range open baffle mid has worked well for me and I recommend it.. There is a lot of appeal in having no crossovers in the critical range. I still think an open baffle might be the first thing to try- you can pick up a pair of solid core doors at a construction supply place with pretty veneer for less than $100 each, or get used ones for almost nothing... slap in the TT's and ribbons, and start experimenting.
To create dipole treble, you could use more of the same tweeter faced to the rear....or use something like the AC 2si at $60? Would it still be crossed over high enough to not be overstressed? Being about 3db less efficient, has about exactly the right output, without any padding.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=276-400
The TT, Brown Soun headquarters are about 20 min. from my house, I should get on the bike and head that way sometime.
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...
Anyone have a look at the spex file for the 8 inch? Might be The condo-sized wideband OB driver...
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.
www.abrown.com --->Sales
one and the same. They also have hempcones for retrofit into certain JBL bass units. 2115 is one, I believe.
SunRa said:
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.
jeff mai said:
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.)
Lynn Olson said:
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.
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 .
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 .
Lynn Olson said:
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?
Cappy said:
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?
jeff mai said:
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.