I’m fortunate that I’m a typically seated listener so no need to stack the Heils for me…..I bought a pair ‘just because’ when someone here alerted me to the pair sale price.
Here’s the thing about AMTs….all of em by design when they’re reasonably well made………the clarity is simply better than anything else. I attribute it to the method they use to create sound.
I haven’t for formally started a project yet but I’m experimenting with them sitting on top of some sealed quick and dirty boxes with my favorite mid of all time……the B&C 8pe21. I brought the B&C flat right to the top of the box so the distance to the Heil is 2.5”. Using MiniDSP I’ve got em crossed right now at 3k. The B&C cone is really only 6.5” so the directivity doesn’t fall off on em til 2.5 and it’s very gradual. This week I’ll be measuring em with some cardboard lenses over the ugly octagon frame and see if I can extend that without messing up response. Got some XPS pink foam too to try and do a radius edge kinda like the B&W 800 series mid.
The B&C mid will play obnoxiously loud without any stress down to 300hz in a .7q box so if this works, I think I’ll do dual oppose woofers firing out the sides like KEF…..two 8” Dayton Reference 8 ohm subs maybe.
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I have made some thing similar
Are those ESS Heil AMT drivers and magnet without the black housing?
I've been truly impressed by these old, OG Pyramid JBL clones (when you can find them) firing straight up to the ceiling. When firing straight to the ear, you do notice their sound signature is different from AMT drivers, or actually any drivers like dome tweeters, etc, but once you fire them to the ceiling, all that goes away and you get a continuous walls of ambient air and sparkle.
Too bad one came with cheapo electrolytic cap and the other with cheapo MKT cap. Only large enough film caps I had laying around were some Mundorf Silver/Oils...😆
I've been truly impressed by these old, OG Pyramid JBL clones (when you can find them) firing straight up to the ceiling. When firing straight to the ear, you do notice their sound signature is different from AMT drivers, or actually any drivers like dome tweeters, etc, but once you fire them to the ceiling, all that goes away and you get a continuous walls of ambient air and sparkle.
Too bad one came with cheapo electrolytic cap and the other with cheapo MKT cap. Only large enough film caps I had laying around were some Mundorf Silver/Oils...😆
That's what I was afraid of. That magnet alignment only works with the first few folds of the diaphragms on each side. Since the middle can't do anything (because of no motor, it's literally a huuuuge air gap), the few actual working folds are acting like separate tweeters. This will result in horizontal interference and also very low spl.
To fix it, at least run some ferromagnetic metal stripes horizontally on the front and back, touching the magnets.
I send a picture of a n AMT i build that is made with 3 diaphragms .
I am very pleased with sound and sensivity .It playes down to app 600 hz.
I am very pleased with sound and sensivity .It playes down to app 600 hz.
Hello
If you look at a factory Heil they have "fingers" that extend, from the magnet structure, across the diaphragm and only leave a couple of the folds not covered. If you look at the DIY the 'fingers" are missing. That implies less magnetic flux interacting across the diaphragm surface where the "fingers" are missing. Ideally you want uniform flux density across the entire width of the diaphragm.
That's my take FWIW
Rob 🙂
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That is right.
I have tried both and like the "open" one more. 🙂
This one like the Kitaro from Heill
And this one alike the great Heil
I have tried both and like the "open" one more. 🙂
This one like the Kitaro from Heill
And this one alike the great Heil
Hi is this model TW57 4 ohm ? Me too am looking for a nice sounding tweeter specifically to fire towards ceiling.
Thanks
That's it. I don't think it's 4 ohms though. Specs say "4 Ohms to 8 Ohms impedance," and judging by which cap comes with it and how low they play, I suspect closer to 8 Ohms when calculating cap values. Just remember this thing weights 10.5 Lb and the square part is 6.25"x6.25" so make sure you have room.
This one comes with cheapo 3.3 uF cap, and that probably plays too low for our purposes. I would try 2.2-2.7 uF.. or even less if going for supertweeter territory.
This one comes with cheapo 3.3 uF cap, and that probably plays too low for our purposes. I would try 2.2-2.7 uF.. or even less if going for supertweeter territory.
0813240948 by drjlo2, on FlickrAfter experimenting on my main rig for awhile, I've come to the temporary conclusion that triple-stacked Heil AMT's in dipole mode don't really need that extra ceiling-firing bullet tweeter. I mean, there is plenty of dipole room-bounce already, and the main system has had room correction, so the highs are already calibrated for the room. However, my experimentation was limited by the sheer size and weight of the bullets which limited the location I could place them on. I have a feeling things may improve once I can place them higher on some kind of stand, but farther away from the main AMT stack. TBA..
0812241925_HDR by drjlo2, on FlickrOn the other hand, I also discovered that my desktop bookshelf speakers also benefit greatly from the (smaller) bullet tweeters firing to the ceiling. So I believe more conventional speakers with more conventional tweeter arrangements are the ones that will benefit the most from ceiling-fire. So even though I bought the bullet tweeters to try with my main system, it's actually my second and third system that benefited greatly. Such is audio...😀
My "Twin Towers" that are open baffle above 600Hz use one rear firing tweeter for 'Air Reflection' 🙂
Dang. Some music genre sounds preferable via AMT stack and others preferable via 1.4" compression driver/horn. What I need a way to switch between the two speaker setups with a click of switch from the listening seat 🤔
1001241112_HDR by drjlo2, on Flickr
1001241112_HDR by drjlo2, on FlickrDid you have a chance to measure the drivers before and after, particularly the verttical dispersion?