Another ESS AMT-1a pyramid rebuild thread

decooney said:
Okay, kind of what I was pondering to a degree but not with the confidence and time needed to do it correctly. I like the idea of working to emulate what essNeff and others have sorted out with their electronic crossovers. I have studied Ralph's setup a bit however I'd prefer going with fewer / more efficient woofer drivers - probably easier said than done and probably why not too many have claimed to actually master a good 3-way with a passive crossover with the big Heil yet. After I gave up failing multiple times, for my current DEC-AMT28 build I was fortunate enough to work up a very basic design and a friend of a colleague (now retired, not available any more) helped me update an re-design and build my current crossovers with testing inside an Anechoic chamber. I feel lucky for that, and it was expensive to do. It would be interesting to speak with Ralph to see if a more simplified 3-way driver layout could be applied based on his prior testing results and such. Thanks.
Click to expand...

I would figure that the critical part of the Fifth Row crossover would be the low-pass for the Midrange and the High-Pass for the Heil. Wouldn't the same settings he used for his woofers, when corrected for the impedence of different woofers, apply?
 
I have my AMT set up in series with a 5 ohm resistor (~8.2 ohms) to an 8 ohm L-pad. The input to the L-pad has a 4 ohm resistor preceeded by a 6.8 mfd Audlyn cap. Based on a 12 ohm load, this equates to about 1,950 Hz. This is just the point where Jonnie Mitchell looses the "dark cloud" in her voice. Without the 4 ohms, there was a "disconnect" in the response between the Heil and the 10".

And I'm loving it! I may even try 5 ohms, but may loose too much volume.

 
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My experience so far is that Active to Passive doesn't necessarily correlate. Active is much easier to get right.
The DCX 2496 can room correct with it's mic., a nice option.
 
toddalin said:
I have my AMT set up in series with a 5 ohm resistor (~8.2 ohms) to an 8 ohm L-pad. The input to the L-pad has a 4 ohm resistor preceeded by a 6.8 mfd Audlyn cap. Based on a 12 ohm load, this equates to about 1,950 Hz. This is just the point where Jonnie Mitchell looses the "dark cloud" in her voice. Without the 4 ohms, there was a "disconnect" in the response between the Heil and the 10".

And I'm loving it! I may even try 5 ohms, but may loose too much volume.

Click to expand...


On my current 2.5 way AMT crossover configuration, once my colleague was able to help me to get the L-pad an other resistors out of the circuit, only then did my custom speakers truly open up and the heils really began to sing and blend with the woofer(s) and bring in midrange like I'd never heard before. In fact, I'd go as far as saying they sound nothing like my original AMT Monitors or 1Cs did with the original factory crossovers. This perhaps is the reason some folks are into active crossovers with AMTs more than ever, but again, that involves more variation in amps and and more interconnects I'd prefer not to deal with. Tried this a while back with the ESS Eclipse crossover. Sounded nice but still introduced something else in signal path between my tube preamp and tube amplifier thus degrading the sound back down again. Still looking for the most minimalistic 3-way passive crossover possible and not damage the heil or my amplifiers in the process. I guess that's what keeps us going, puzzle is never quite solved 101% :)
 
At this point, relative to the rest of the system, the Heil is padded way down and I could remove the L-pad just retaining the noted resistors. But, I still intend to redo the woofer porting and expect to loose a bit of volume, so the L-pad may still prove necessary. If the end results reveal that the L-pad needs to run wide open, it will be removed.
 
This compares the JBL L200/300 with the 2241/2251/Heil AMT crossed over as I noted above. As I noted, the Heil removes the "dark cloud" in her voice.

I'm still working on the crossovers (very close) and have yet to address the lack of any padding in the 18" cabinet, and to reduce their tuning frequency a bit. Hear you can hear them when compared to the L200/300. I've been trying to get that dark cloud off Joni's voice for years. This seems to do it.

These are "pure direct" with no room correction, subs, or eq.

 
toddalin said:
This compares the JBL L200/300 with the 2241/2251/Heil AMT crossed over as I noted above. As I noted, the Heil removes the "dark cloud" in her voice.

I'm still working on the crossovers (very close) and have yet to address the lack of any padding in the 18" cabinet, and to reduce their tuning frequency a bit. Hear you can hear them when compared to the L200/300. I've been trying to get that dark cloud off Joni's voice for years. This seems to do it.

These are "pure direct" with no room correction, subs, or eq.

Click to expand...

Even from the camcorder/phone microphone through my small computer speakers, the Heils are special.
But the internet makes your LED TV look like one of those old projection jobs.
 
toddalin said:
This compares the JBL L200/300 with the 2241/2251/Heil AMT crossed over as I noted above. As I noted, the Heil removes the "dark cloud" in her voice.

I'm still working on the crossovers (very close) and have yet to address the lack of any padding in the 18" cabinet, and to reduce their tuning frequency a bit. Hear you can hear them when compared to the L200/300. I've been trying to get that dark cloud off Joni's voice for years. This seems to do it.

These are "pure direct" with no room correction, subs, or eq.

Click to expand...


Nice video. It's truly great to see others trying/testing. Great job, inspiring! Keep up the great work, maybe you'll solve it for us. :)

By the way, I can hear the differences with good headphones on to get an idea. While the ESS amts are brighter and more forward, the JBL L200/300 has a deeper sound stage and further set back. I wonder if part of that is related to them sitting on the floor. I find this older method of floor speakers sitting on the floor makes them sound a bit muffled, even with JBLs. I noticed this on my older ESS AMT Monitors when I had them sitting on the floor, or sound bouncing off carpet. If you take an old pair of any of the large ESS/AMTs and get them off the floor a bit and bring the in-between center of the heil/woofer at ear level, they do sound different once again, kinda like you have it now. Maybe try the same with the jbl set. Would be interested to see what you think then. I can really hear that mid on your ESS in your test. Cool.

Have you ever tried putting your JBLs on a stand, up in the air, maybe with some blocks under the JBL to get it up in the air to the exact same level as the ESS Heil, re-test, compare again?
 
If you look close, you can see that the L200 cabinets are raised ~4" and that volume was added to the interior. I've not tried to raise them further.

The 2241s (and L200s) obviously suffer from floor bounce and no attempt is made to correct it here. The 2235s in the L200s go lower, but are tubbier. The 2241s may even sound better if I turn the cabinets over and put the ports at the top. But they are a bit heavy to lift by myself.
 
Finished my room remodel!

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Porkloin said:
After going through the thread, it's apparent that you're too deeply (spiritually) into the thing to get rid of it. Which turntable is better?
Click to expand...

Loaded question. The Thorens is much quieter now that I added a base (on spikes, atop my new Massif rack). Still need to do same to the XA, but the XA has a barely discernible motor hum. I also have a better cartridge on the Thorens, and it's easier to change from 33 to 45. Eventually, I'd like to have MM on one and MC on the other.
 
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