AMT

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ed

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Re: AMT
« Reply #20 on: 17 Sep 2018, 11:38 pm »
Nick, most digital amps will not tolerate a series 1st order xover. Use a "normal" parallel network and you'll be fine. I prefer the series and I don't care for digital amps so it'a all good for me! As I said, at 800Hz (too low IMO even though it will do it) you can't use a first order network if you listen at 'loud levels" unless you like the smell of melting plastic! Heils typically do not show signs of distress......you just notice the diaphragms are melted.....they will still be playing and maybe not even distorting grossly!

Don't worry about cancellation......wings not needed or else ESS would have done it :)

My experience with the GH goes back to the beginning.........not long after they were out  I had built magnet structures and was ordering diaphragms from ESS. My structures were a clone of the real thing but the pole pieces were glued together instead of being held in a plastic housing. A buddy worked at a metal shop and we cut the pole pieces from a sheet off steel. I bought 1000 ceramic magnets for the project.
Hope this helps.
Ed

dB Cooper

Re: AMT
« Reply #21 on: 18 Sep 2018, 02:53 am »
I remember hearing the ESS AMT-1 (AFAIK the first speaker to use the Heil) on May 15, 1973. (No, my memory isn't that perfect; I heard them the night I took my amp to one of those McIntosh amp clinics; still have a scan of my test chart).

My recollection is of a very detailed sound, maybe a little sibilant and 'etched', which may be attributable to the amplification available in 1973 (not sure what it was but I seem to remember that it may have been the well-known Crown DC-300).

Salk did a 'one-off' speaker using the Heil tweeter a year or two ago, and I seem to remember Dennis Murphy saying that it took a lot of finagling to get the crossover and driver blending right. Perhaps he will see this and have some thoughts.
 

nickd

Re: AMT
« Reply #22 on: 18 Sep 2018, 12:42 pm »
Thanks Ed,
Haven’t decided what crossover route to go yet. My thought are 18 or 24db per octave digital and start at 900hz or so. I can smooth with DSP, but as you know, sometimes you need a trap or notch to make a driver really blend well. More to crossovers than a nice DSP can do sometimes.

Time alignment looks easy using the Heils that’s a huge plus and baffle machining is only needed for the woofer. Tho whole project seems like a high reward moderate effort build.

Thinking of a three way with a Rythmik servo 12” sub on the bottom the Altec 12 as a midwoofer and the large ESS Heil at ear height at 34-36”. The Altec is light and fast and has amazing tone. Might be a keeper.  :D

ed

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Re: AMT
« Reply #23 on: 18 Sep 2018, 01:39 pm »
Nick, get a Crown XLS series amp.......build one or more of these. It's not a joke and the combo of the Crown and a few of these, I only use one,  will slay pretty much anything. I have offered to give one to anyone who could find it by listening. No one has. It hides in a corner behind a cabinet 5 feet from the couch. it is impossible to locate.

Bruce measured it and you can read his results. While it makes no sense, it is superb by any standard..... it is the  "F**king Fantastic Redneck Subwoofer Mark 4:20 Inspired"  The "Mark 4:20"  can be a reference to the King James version of the Bible or Cheech and Chong, you decide!

The thing is not a joke. Follow directions EXACTLY.
Ed
ps.......doing my best to advance the state of DIY into the 20th century :)

ed

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Re: AMT
« Reply #24 on: 18 Sep 2018, 01:41 pm »

Wallacefl

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Re: AMT
« Reply #25 on: 25 Sep 2018, 11:01 pm »
I remember hearing the ESS AMT-1 (AFAIK the first speaker to use the Heil) on May 15, 1973. (No, my memory isn't that perfect; I heard them the night I took my amp to one of those McIntosh amp clinics; still have a scan of my test chart).

My recollection is of a very detailed sound, maybe a little sibilant and 'etched', which may be attributable to the amplification available in 1973 (not sure what it was but I seem to remember that it may have been the well-known Crown DC-300).

Salk did a 'one-off' speaker using the Heil tweeter a year or two ago, and I seem to remember Dennis Murphy saying that it took a lot of finagling to get the crossover and driver blending right. Perhaps he will see this and have some thoughts.
A friend did some measurements on my ESS Heil tweeter and got a similar peak at about 7K as noted by Dennis Murphy...I am on the fence about ever using them at this point but think they could possibly  be a decent midrange driver ie: replace the le-5 in the JBL 100?

dB Cooper

Re: AMT
« Reply #26 on: 25 Sep 2018, 11:07 pm »
Dennis did eventually "beat it into submission" as I believe he described it, but not a good candidate for 'cookie cutter' xovers.

Biamping/ electronic crossover/DSP solutions might work well though.

The AMT-1's I heard back in the day were driven by whatever the primo model of Mac (sponsor of the clinic) was at the time.

skalos

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Re: AMT
« Reply #27 on: 2 Oct 2018, 07:48 pm »
Here is one. 6" woofer $50. 4" woofer $45.  I'm sure they are not up to par with others listed but they are getting decent reviews.

Proof of what happens when a patent life ends, good or bad.


https://www.parts-express.com/dayton-audio-b652-air-6-1-2-2-way-bookshelf-speaker-with-amt-tweeter-pair--300-651