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The Betsy AMT (Read 2527 times)
Randy in Caintuck
Seasoned Member

Tube be ... or not
tube be ... it's a

Posts: 860
The Betsy AMT
09/28/17 at 22:10:00

I'm starting to feel like "Columbo" .....
"Just one more thing, sir" ..... with apologies to Peter Falk .....

The "one more thing" is the Betsy AMT (air motion transformer)

When I first started building Betsy baffles, I offered a model with a dome tweeter to supplement the high frequencies of the Betsy driver and a toggle switch to enable / disable the dome.

After quite a bit of listening, I concluded that there was something "unnatural" sounding about the top end when the dome was in the mix. I experimented with tons of various crossover points and was just never totally happy ..... so I stopped offering the version with the dome tweeter and decided that I was more than content with the "sweet" and natural sounding high frequencies of the Betsy driver "flying solo".

After receiving a boatload of very positive emails from customers, I concluded that a lot of folks agreed with my decision.
While the Betsy driver is not super-extended at the top end, it has plenty of detail and air and is easy on the ears for extended listening sessions with any decent source and amplifier.

However .....  
I continue to receive emails asking if I would be willing to build a pair of Betsy baffles with a tweeter.
Truthfully, I had decided never to do so and ignore the requests because I had concluded that the whizzer cone extended the high frequencies to a point that there was a less than musical overlap with a "real" tweeter.

Recently, something popped up that made me rethink the situation.
After confirming that the Betsy driver is available without the whizzer cone, I thought that this might change the entire situation ..... and it does.

Without the whizzer, the driver is still pretty extended and things like cymbals are still audible ..... but a lot of the "air" and harmonics are missing, so it certainly isn't reaching up as high as the Betsy with a whizzer.

I decided that if I was going to mess with this at all, the speaker would have to be a total "dipole" and the tweeter would have to radiate front and rear as the Betsy driver does. I had a pair of Dayton Audio AMT drivers on hand which met that criteria, so I made a baffle and started experimenting with crossover points for the AMT driver.

A hundred hours or so later, I am happy with the results and will bring a pair of the speakers to the Decware Fest to get some feedback from the "experienced ears" in attendance .....  

I have had a few visitors check them out and the feedback has been positive to this point. The sound is certainly "different" than the stock Betsy baffles. I can make an argument for either and I think that it will depend on the associated front end and amplifier in use to determine which speaker is "better".

If they don't fly, not a biggie ..... I'm perfectly happy to have my home system built around my stock Betsy baffles ..... but this will be an option for those who insist on having "real tweeters" in their speakers.

Just one more thing ..... photos .....

Larger photo here.

The speaker in the photo is rift sawn red oak plywood with red oak veneered edging .....

Looking forward to seeing everyone in East Peoria,
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CEC TL5N belt drive CD transport
Cambridge Audio Azur 851N DAC / Streamer
U-Turn Audio Orbit Plus turntable
Decware SE84UFO amplifier
Caintuck Audio Betsy Open Baffles
Caintuck Audio Lii 15 Open Baffles
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Steve Deckert

If the 1st watt
sucks why continue?

Posts: 4846
Re: The Betsy AMT
Reply #1 - 09/30/17 at 02:45:52
Dipole tweeter...  nice...
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Posts: 429
Re: The Betsy AMT
Reply #2 - 10/01/17 at 13:23:41
great idea randy!

can't wait to hear them this week!
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CSP3 25yr, CAD 120s MKII, Sunfire Signature600, Sota Star Sapphire, SME309, Hana SL, JC3+, Schiit bifrost multibit, CXC, MG1.6QR w/ ext xo & mye stands, OB Augies. herbies iso, VH audio flavor diy pwr cords, Beden 8402 & Dueland IC's,
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