Moved!
Hello, paulfx.....
What a coincidence! Only last week I started restoring my set of Amt-1's. Then out of curiosity I decided to hook up the big ND-Heils. I had moved to a new location almost 3 years ago, and these were still boxed up sitting under the house.
I picked up some Eclipse 10-inch wooofers for the Amt-1's, and they work quite well in the standard version of the system. Running the big Heils full range on top with only a 20 mfd cap in line, and a coil for the woofer, I was treated to sound even better than I remembered it. Had a few friends audition them, and all had positive comments -- "great detail"..."no listening fatigue"..."smooth...." (must have proper placement and listener position). I'll do a more complete review when time allows.
Glad to see you're getting closer on your project as well.
Hello, paulfx.....
What a coincidence! Only last week I started restoring my set of Amt-1's. Then out of curiosity I decided to hook up the big ND-Heils. I had moved to a new location almost 3 years ago, and these were still boxed up sitting under the house.
I picked up some Eclipse 10-inch wooofers for the Amt-1's, and they work quite well in the standard version of the system. Running the big Heils full range on top with only a 20 mfd cap in line, and a coil for the woofer, I was treated to sound even better than I remembered it. Had a few friends audition them, and all had positive comments -- "great detail"..."no listening fatigue"..."smooth...." (must have proper placement and listener position). I'll do a more complete review when time allows.
Glad to see you're getting closer on your project as well.
No--I think the reference was to the DIY Heil I posted over 10 years ago at: DIY Heil
I also wrote the original DIY Heil article for Audio Amateur back in 1975 (it appeared in the 2/77 issue). The link to the original article is here: http://www.audiodevelopers.com/misc/AA_article/ . Notice the "Update", which describes the etched diaphragm. Hard to believe this is almost 40 years ago.
I haven't made any Heils in the last 10 years, but now that I'm retired I intend to finish off the cylindrical Heils that I started a couple of years ago. There is a "mini" version and a larger one that uses 4 of the Aurum Cantus diaphragms wrapped around a 2" cylindrical magnet structure. It's a pretty interesting project. In order to curve the diaphragm I had to make a fixture that I could heat with a blowtorch to soften the plastic frame. I'll write a build article on it when I get back to it.
Bernt, aka Bandsei,
I am not at your level! In your AMT there is nothing between the pleats and the listener.
In every land, there is some aspect of art where the bar is high but the natives are not aware. For example, here in North Carolina USA excellent furniture is assumed, and can be found in garage sales. In Denmark are superb speakers everywhere? When you travel, do you notice how bad speaker systems are everywhere else? By the way, are you in an audio-related business? Pardon my questions, but I'm curious about your audio zeitgeist.
Thanks,
Paul
I am not at your level! In your AMT there is nothing between the pleats and the listener.
In every land, there is some aspect of art where the bar is high but the natives are not aware. For example, here in North Carolina USA excellent furniture is assumed, and can be found in garage sales. In Denmark are superb speakers everywhere? When you travel, do you notice how bad speaker systems are everywhere else? By the way, are you in an audio-related business? Pardon my questions, but I'm curious about your audio zeitgeist.
Thanks,
Paul
I was another Dane that inspired me to make the magnetsystem like I do,see the start of my Tread: Diy AMT.
I notice when systems are bad sounding.I have not noticed big difference betweene Denmark and the Places in Europe I have visited.
I am an electrician .
I like the challenge.To build alike or better,and cheaper than manufactores.
Bernt
I notice when systems are bad sounding.I have not noticed big difference betweene Denmark and the Places in Europe I have visited.
I am an electrician .
I like the challenge.To build alike or better,and cheaper than manufactores.
Bernt
Update
I had to repair one of the big diaphragms in the setup. (still had my aluminum solder and flux kit from years ago). Actually need to make new diaphragms, as the two are now not perfectly matched. But instead, decided to try adding "supertweeters" using the elements salvaged from ancient Amt bookshelf speakers.
I used 3/16 inch round steel stock cut into 3 inch bars, 2 magnets and 2 corner braces for each. They are about 5-6 ohms DCR, and I'm using a 1 mfd cap in line. Magnetic gap is 1/2 inch, and even though the diaphragm thickness is not much over 1/8 inch, output is acceptable. Oh, and I re-foamed my JBL (2215) subwoofer to help out on the bass.
I had to repair one of the big diaphragms in the setup. (still had my aluminum solder and flux kit from years ago). Actually need to make new diaphragms, as the two are now not perfectly matched. But instead, decided to try adding "supertweeters" using the elements salvaged from ancient Amt bookshelf speakers.
I used 3/16 inch round steel stock cut into 3 inch bars, 2 magnets and 2 corner braces for each. They are about 5-6 ohms DCR, and I'm using a 1 mfd cap in line. Magnetic gap is 1/2 inch, and even though the diaphragm thickness is not much over 1/8 inch, output is acceptable. Oh, and I re-foamed my JBL (2215) subwoofer to help out on the bass.
Well, the 2 smaller units I improvised did not work out as "supertweeters." Their response had more output in the upper midrange/high frequencies, and less in the top end than my large Neil Davis AMTs. They may work well in a small two-way system crossed over about 2K, as they sound very good by themselves subbed in for the larger Heils.
However, I was able to get better sound out of the larger units by pointing the cabinets inward toward the center of the listening area, and then angling them upward slightly, 5-10 degrees or so.
On axis, the response is slightly lower in the 1500 hz region with a rising response up to 15K. moving sideways off axis, the response flattens out nicely, so there is a good overall polar sound field. This was near-field room frequency measurements made with a Heath RTA. The crossover is simply a coil and cap, allowing a large overlap in the midrange, with a nominal crossover point in the 1K -1.5K region.
Placement and listener position is important (almost critical) but I am very pleased with the sound these things produce. At this point I don't see the need to add a "supertweeter." And power handling / output level is great.
However, I was able to get better sound out of the larger units by pointing the cabinets inward toward the center of the listening area, and then angling them upward slightly, 5-10 degrees or so.
On axis, the response is slightly lower in the 1500 hz region with a rising response up to 15K. moving sideways off axis, the response flattens out nicely, so there is a good overall polar sound field. This was near-field room frequency measurements made with a Heath RTA. The crossover is simply a coil and cap, allowing a large overlap in the midrange, with a nominal crossover point in the 1K -1.5K region.
Placement and listener position is important (almost critical) but I am very pleased with the sound these things produce. At this point I don't see the need to add a "supertweeter." And power handling / output level is great.
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