Has anyone used or heard these? What did you think of them?
Heard a pair in Jeff’s Spirit Winds with the Rev 9900, a phenomenal 2way.
Heard several in commercial offerings at AXPONA, but the Polymer Audio Research 4ways showed and sounded fantastic.
Expensive, but a good driver they do make.
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Thanks Ben.
The spirit winds were simply amazing. So were the vapour audio ones at Axpona.
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Thank you Ani.
How was the bass extension and how clean, punchy and dynamic was it?
Ben, could you offer a comparison to Purifi?
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I have Purifi drivers. Very interested to know as well.
Not sure I can compare them honestly. They are very different drivers.
AT are large VC, inside magnet, poly-blended cones. Shorting rings? Shorter xmax and higher sensitivity follow.
Purifi are longer throw, lower sensitivity, blended paper cones, with weird surrounds.
They will measure different as they are very different. Ejvind Skaaning, Bruno Putzeys, and Lars Risbo however do know what they are doing.
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If you can get past the fugly appearance of the Purifi they are hands down the best performing woofers on the market today. It is likely a case of 90% though, as in some other drivers probably offer 90% of the performance at less than 90% of the cost, although I believe AT drivers to priced even more than Purifi. I can’t do US to Canadian dollars conversion in my head.
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I have the 6.5” Purifi midrange drivers. They are incredible. Using them with a 2” soft dome mid, Bliesma T25B tweeters and four RSS210HO-8 subwoofers. End game system ( so far) 
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Which 2” dome mid?
That never stops you from getting AT drivers too… Different flavors for different seasons!!!
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Tang Band 50-1426SE. Crossovers are at 200hz, 1300hz and 3600hz. I was shooting for 1000 hz and 4000hz but ended up were they worked.
When Kerry and I were working with Salk before he retired, we independently heard the Song Beat 3s, which used an AT midrange, and we both noted something special about the midrange. I had a similar experience with the Spirit Winds.
Salk had some speakers using Purifi drivers and I’ve also used them myself, and while they all measure phenomenally and sound excellent, I haven’t heard anything in them that makes me want to pay the premium over, say, a Satori driver or an Illuminator if you need the extra excursion.
AT drivers are also not cheap, but every time I hear them, they sound magical. I will say, though, that I’ve never heard anything larger than the 7”, so I have no experience with their larger, true bass drivers.
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Thanks for your input Dan.
The main advantage with AT drivers, from my view of loudspeaker system design, is being able order customized drivers in small quantities. Other companies don’t even want to work with you unless you can order hundreds of units at a time. This makes them particular interesting to builders looking to enter niche markets, where exclusivity is part of the appeal for their potential customers.
This is kind of anti-thesis to DIYers, who, like the open source software community, tend to value transparency, collaboration and open participation over proprietary trade secrets or patent monopolies.
However, suppose you like an existing product but want a a higher voltage sensitivity variant. Shorter voice coils can be requested (lower moving mass and sensitivity), different cones for unique aesthetics (you supply the cone to AT), different former materials e.g. titanium, or more magnet strength (higher β)…
So the standard 15 H 52 12 06 SDKM, which is a 4.5” diameter cone midrange can be instead ordered as a 15 I 52 06 09 SDTM-LR
I - larger (130mm) diameter ferrite magnet
06 09 - air gap height 6mm, voice coil height 9mm → shorter voice coil, underhung geometry for more linear BL(x), +/- 1.5mm instead of +/- 3mm x-max (for a pure mid playing > ~300Hz, 3mm excursion will never be reached)
T- titanium voice coil former (stiffer than alu but lower electrical conductivity)
LR- top and bottom plates machined with curves/round-overs
Whether you accept the advantages or disadvantages depends on your required application. One could also argue that a smaller voice coil eg. 1.5” or smaller, and a neodymium motor would further raise the voltage sensitivity even higher, but they don’t offer that.
In the end you will get a unique product, without having to manually assemble your own transducer using parts from magnet, cone, voice coil, basket suppliers, etc.
But if you’re NOT looking to sell your creations, you can buy transducers from one of the many other manufacturers, off the shelf…
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Yeah, I do like the fact you can design the driver to your liking. That was the main reason I was looking into them.
I’ll have to look into the AT for dedicated midrange use. Not enough high end dedicated mids out there. Actually, not enough dedicated mids at any price point out there.
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I did some googling yesterday. Anyone selling AT mids for retail?