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Double Stack ESS AMT-1 with Wings--Possible Kit for Heritage


Chris A

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13 hours ago, Chris A said:

I would put the AMT-1 assembly and bass bin where you expect to place them when listening to them, then place a lot of absorbing material around the full path from the loudspeaker and the microphone, as thick as you can make it and 3 feet wide.

 

Chris

My current listening space is treated with ultra touch and roxul panels, so I should be good there. I do not however have the dsp yet. I was hoping to do some measurements with the heils alone but I may have to wait until it arrives.

 

19 minutes ago, DizRotus said:

It’s unclear to me.  Are the units available from Amazon and/or Simply Speakers for ~$177 new units made by Heil AMT, NOS,or something else?  I thought Heil AMT was out of business.  Are the $177 units worthy of experimentation and use?

 

Fortunately, I live close to Claude @ClaudeJ1 so I can hear these in person, although the last thing I need is to hear something that makes me unhappy with my current “last speakers.”  

 

Claude, How would/could these be incorporated into a MEH?

ESS is still in business. You can order the heils from them directly.

 

http://esslabsusa.com/heil-amt/

 

 

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21 minutes ago, DizRotus said:

It’s unclear to me.  Are the units available from Amazon and/or Simply Speakers for ~$177 new units made by Heil AMT, NOS,or something else?  I thought Heil AMT was out of business.  Are the $177 units worthy of experimentation and use?

 

Fortunately, I live close to Claude @ClaudeJ1 so I can hear these in person, although the last thing I need is to hear something that makes me unhappy with my current “last speakers.”  

 

Claude, How would/could these be incorporated into a MEH?

I ordered mine for $155 per from the link that Chris provided on page 1

4 minutes ago, Thaddeus Smith said:

 

Not yet - I got an automatic "your order confirmed" email just over a week ago, and no news since. Not going with the minidsp.. Going to be using a Yamaha sp2060 instead.

Where did you pick up the SP2060?  

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39 minutes ago, No.4 said:

I was hoping to do some measurements with the heils alone but I may have to wait until it arrives.

You can do some simple first order filters with the AMT-1 assemblies at the crossover frequency that you intend to use to hear the difference, with the knowledge that there will be EQ required to get the total loudspeakers within a ±2-3 dB flatness.  I believe that the AMT-1s have a very flat input impedance of 3.7 ohms, and the La Scala bass bins have an approximate Zin of 10-11 ohms at 400 Hz, so you can design the values of a passive first order base on those values (or you can use the existing La Scala passive crossover for the bass bins only).  That would get you down to a single capacitor and resistor (attenuator) for each loudspeaker to get close enough for first order approximation (pun intended).

 

Chris

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3 hours ago, DizRotus said:

Claude, How would/could these be incorporated into a MEH?

Yes, Claude, how would you do that?  🤔

 

BTW: I have a good idea of how to do it (first rate) and I've been working on those design details a bit, but it requires a special horn throat...and it's currently on my list of things to do after the current items on the things-to-do list are realized.

 

Chris

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1 hour ago, DizRotus said:

I thought Heil AMT was out of business. 

"The reports of [their] death are greatly exaggerated" Mark Twain

ESS has been in business since the late 1960s (with a hiatus in the early/mid-1990s, IIRC).   I don't believe that they are going out of business anytime soon.  Just remember that Nelson Pass got his start in the industry with ESS in the early 1970s, a couple of weeks before Oskar Heil showed up.

 

Chris

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3 hours ago, Thaddeus Smith said:

Not going with the minidsp.. Going to be using a Yamaha sp2060 instead.

If you look over in the "I finally got around to triamping my K-horns" thread, you'll see that both Greg Oshiro and I used a Yamaha SP2060 (probably the same DSP crossover, in fact).  I've got a somewhat esoteric converter coming from China that handles the digital-only conversions from USB (on the laptop) to AES/EBU on the Yamaha.  I looked for a HDMI-->AES/EBU converter but none were found in my searches. 

 

USB of course has the problem of suppressed clock jitter issues, so the converter box that's coming has an input buffer and an accurate clock (a DAC clock, in fact) to accurately convert to the digital output AES/EBU without jitter issues--and the price of the converter box reflects the addition of those resources--even from China.  If it works out as I think it will, I'll post the identification of that converter, the source where I ordered from, and the price, etc.  It's a lot less expensive than a RME HDSPe AES‑32 card that requires a desktop PC internal slot that etc6849 (Ellery) uses for his surround-sound array.

 

The advantage of the converter is that it avoids having to go through a DAC-->ADC-->DAC that you get with most DSP crossovers--keeping everything in the digital domain from the source (i.e., a computer or digital disc player in my case) until you get to the output of the DSP crossover.  I'm about to find if this is audible to eliminate that extra D-->A-->D sequence.

 

Chris

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Been waiting seems like forever for today to get here:

 

Not totally finished, but ready to begin testing.  Still need to trim the rod length for that finished look and need to add black clay to smooth out the driver to waveguide transition.

 

Now on to work on the other channel. Then, set up xovers, then run some sweeps to show what the whole speaker will do and on to the best part.....listening challenge!

 

FontSM.jpg

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Some close ups so you can see how I put it all together. Details on little tweaks to follow.

 

Build note: I added very thin black tape insulation to the top end of the waveguide.  I did not want the top to vibrate and possibly cause problems, so the tape should prevent any vibration. Decided to place the barrier strip on the side to keep the wires away from the back of the drivers and out of view from the center of the room.  Wiring is somewhat temporary for now. Placed the entire platform on vibration isolation pucks to again prevent vibrations from bass bin affecting the AMTs.  Not sure if that is even necessary, but doing the best I can to optimize what the AMTs can do.

 

Suggestions are welcome!

 

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For those of you who have taken the leap and ordered AMTs, but are now wondering if this is worth it.....the answer is an unequivocal yes!  Press on.

 

I created the no-name crossovers at 1khz, two way and mimicked a 24dB/oct L/R crossover.  Set up a L/R crossover on one channel and used the graphic function to mimic the slope on another channel.  Took two EQ slots on the Xilica,  one is a -30dB shelf and then used one EQ to shape the slope.  Below is an example.

 

After setting up both channels and I just couldn't stand it, so decided to jump right into listening. Did not EQ, did not set timing, just set the xover and turned them on.  This is most definitely going to work for me. Even without tweaking and optimizing the HF/LF timing and EQ....it sounds really, really good to my ears.  I still get blown away by the expansiveness and accuracy of the sound stage.  Vocals sound excellent, so mid-range is not a problem.  If I do have any issues at the crossover region, I will simply use a gentler slope on my bass bins to fill any missing parts....but I don't think that will be necessary. When I run sweeps, we will see how it looks technically.

 

I am very happy with this project thus far.  Seems to me it can only get better and I like the way it sounds right now. 

 

Current plan onward is to fine tune the system. First, add the clay and finish the wing structure properly.  Then set the timing and EQ at 1kHz as a baseline for normal use as a starting point.  Then, I will start experimenting with lower crossover points until I find the sweetspot for my HF/LF combination. 

 

Sensei, @Chris A, you will have to venture north for a listen some time. Lunch will be on me.

 

XoverSM.jpg

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On 1/12/2020 at 3:16 PM, Rudy81 said:

Sensei, @Chris A, you will have to venture north for a listen some time. Lunch will be on me.

My son and daughter-in-law live up your way (in Allen), and they just had our first grandchild this summer, so I might take you up on that.

 

Chris

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11 minutes ago, Chris A said:

My son and daughter-in-law live up your way (in Allen), and they just had our first grandchild this summer, so I might take you up on that. 

 

I've got a few things to do in the short term however--like getting Khorn clones dialed in properly and getting ready for the SWAG thing in April with test rig, Khorn clones (they have full range directivity to demonstrate some subjective aspects of phase flattening), setting up REW/DSP crossover demos, and perhaps even a demastering demo.  Teaching adjunct on the side  taught me to bring many examples...ready to go if someone asks the right questions.

 

Chris

 

You would be welcome any time.  What is this SWAG thing?  If it is a public venue, e-mail me info please. 

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I spent a good portion of the day updating and cleaning up my neglected laptop for this project. It was originally purchased to exclusively run REW, but I have not needed it for a while. Anyways, it is fresh, and now has the MiniDSP 2x4 HD software downloaded and ready to go. When I will actually receive my DSP unit is a whole other question. 

 

I did a little reading on the MiniDSP site that answered many of my questions and made this project a little less intimidating. the user manual https://www.minidsp.com/images/documents/miniDSP 2x4 HD User Manual.pdf 

is very straightforward. If you are thinking about this project but having reservations read through this manual. then read this https://www.minidsp.com/applications/digital-crossovers/minidsp-2x4hd-application/283-2x4-hd-twoway  I am very excited about the potential of this project and the doorway into active crossovers. I don't want to get ahead of myself, but, I can already see this opening up unlimited potential for future projects that would normally have been limited by passive crossovers. 

 

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3 minutes ago, No.4 said:

I spent a good portion of the day updating and cleaning up my neglected laptop for this project. It was originally purchased to exclusively run REW, but I have not needed it for a while. Anyways, it is fresh, and now has the MiniDSP 2x4 HD software downloaded and ready to go. When I will actually receive my DSP unit is a whole other question. 

 

I did a little reading on the MiniDSP site that answered many of my questions and made this project a little less intimidating. the user manual https://www.minidsp.com/images/documents/miniDSP 2x4 HD User Manual.pdf 

is very straightforward. If you are thinking about this project but having reservations read through this manual. then read this https://www.minidsp.com/applications/digital-crossovers/minidsp-2x4hd-application/283-2x4-hd-twoway  I am very excited about the potential of this project and the doorway into active crossovers. I don't want to get ahead of myself, but, I can already see this opening up unlimited potential for future projects that would normally have been limited by passive crossovers. 

 

 

I have been down this road and can tell you that it is a very worthwhile journey.  The amount of flexibility you get when active, is amazing. 

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