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

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@hallcon83

 

When both of the sides of the horns are glued together the top and bottom can be built. Basically the heil and both sides are put together on top of a piece of plywood and the shape of the top is traced out. The shape was then cut out with a jigsaw leaving some material towards the edges. Then the top and bottom was screwed to the sides ensuring everything was square. The screws will allow the tops and bottom to be removed from the sides until final glueing. Once all put together I ran the tops and bottom through the router using a flush cut bit. I used the the vertical sides as the guide to run the bearing along. This produced a good edge, but still required some sanding and filling. The point where the sides come together did still have some round over due to the router bit. I just used a file to get points sharp. There is some bonds and filler underneath to get a good surface for the veneer.

 

Hopefully that helps.

 

I found the photo below as I was routing the tops. You can see a little better how rough the edges were before final sanding and filling.

 

 

F9C82EDE-550D-4AD8-9F78-63222B77C95A.jpeg

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-  Hi No.4 , Thank You, that's very kind I really appreciate the help, I've built a few things  , but just beginning to try do any actual real quality wood working. Have the Table saw, Jigsaw, and Router , but haven't learned to use the Router yet, need to build a table for it still, your description and pictures are very helpful! 

 

- This is a Great Thread , can't wait to see someone - ( Hint Hint, to our fearless Leader - Chris ) to try the double stacked AMT's in a MEH Horn !!!

 

-   I apologize for moving off topic for a moment, but I'm part of a Group buy of the New Patented Purify 6.5 in. woofers over on diyaudio , the new woofers are from a new research focused company in Denmark founded and staffed by a distinguished group of Hi-Fi industry heavyweights , it's a collaboration between eight of some of the sharpest designers in Commercial audio - Purifi's initial offering is the PTT6.5W04-01A , 6.5 inch woofer, a design that reduces distortion by tens of db's while remaining linear to extreme excursion levels.This promises to allow bass depth with low midrange distortion that is normally the providence of large speakers using 12 and 15 inch woofers in jumbo multi-cubic foot boxes to be had from a 1/2 cubic foot /liter enclosure 2 - way system.  The new woofer is the result of approximately four years of research and the new 6.5 inch drivers have far less distortion than any other single driver being made today -- that adds up to some real fun for diy guys!

 -  That was all to say - or ASK if it's okay I would like to post a link to This thread over there to inspire the guys - the Mid-Woofers just came in and everyone is looking for the best Tweeter option to complete the speaker designs, and I think that for some people your work on the Stacked AMT's could really be an answer to that design. - ?????  --- 

 

Thank you, Dean  

 

---  PS. If you get a chance head over to Purifi Audio - the new 6.5 woofer is wild!  

------ ( I wish I could post a link.) ----  Iv'e been following a lot of threads here over the years - And some day I really hope to have a pair of maybe Cornwall's, or La Scala Klipsch speakers..... but I'm new to posting here on the Klipsch Forum and I found out the hard way that I shouldn't post a link for a while - LOL

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I had a quick question for Rudy81  (or any one else) , do you know the dimensions across the front of the wave guide when using seven inch wings? - Thanks, Dean

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2 hours ago, hallcon83 said:

I had a quick question for Rudy81  (or any one else) , do you know the dimensions across the front of the wave guide when using seven inch wings? - Thanks, Dean

 

My wing stack has the following dimensions: 13.5"Hx15.5"Wx14.5"D. Construction is primarily 18mm Baltic Birch.

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On 5/14/2020 at 2:04 PM, 13stoploss said:

ESS' most popular speaker is the AMT-1(A-D), the pyramid shaped successors to the AMT-1; the A-D models feature a 12" front-facing driver and 12" rear-facing passive radiator. While passive crossover changes fluctuated over the years, the woofer generally crossed over to the AMT at 800hz. The speaker itself is 6 ohm with a 91db efficiency, even though ESS has only ever used 4 ohm drivers in all its AMT lineup. Frequency extension ranges from 38-23,000.

Have had one of these I refurbished with new woofers, passives, and AMT diaphragms. The new ones didn't sound different from the old ones.

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This thread is really interesting! I found it from the Purifi thread on Diyaudio.

 

I use Heil AMT in open baffles crossed over with a 15" woofer, so a lower crossover frequency would be great. I wonder how big the contribution is of reducing acoustic shortcircuit by the Wings. E.g. what if you would make panels on the side of the AMT perpende iculary? And could it be beneficial to add a panel on top of the AMT, from left to right, pointing straight up? Furthermore, it could be an Idea to cover the magnet structure more. I heard this causes unflatness around 5-7 kHz...

This calls for some experiments...

 

Fedde

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6 hours ago, Fedde said:

This thread is really interesting! I found it from the Purifi thread on Diyaudio.

 

I use Heil AMT in open baffles crossed over with a 15" woofer, so a lower crossover frequency would be great. I wonder how big the contribution is of reducing acoustic shortcircuit by the Wings. E.g. what if you would make panels on the side of the AMT perpende iculary? And could it be beneficial to add a panel on top of the AMT, from left to right, pointing straight up? Furthermore, it could be an Idea to cover the magnet structure more. I heard this causes unflatness around 5-7 kHz...

This calls for some experiments...

 

Fedde

 

Get tinkering and post your impressions + measurements. :)

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I realized after the AMT builds, that I should try to optimize my 2-way speakers by trying to go full dipole vs. using a ported LF cabinet.  After much research I found that an open baffle H frame with dual 18" Goldwood drivers might do the trick.  So, built a prototype and was able to confirm that  in fact, I could go fully dipole and achieve very good full range frequency response. 

 

Yesterday I hooked up the new H frames.  Today, I ran REW and got extremely good results for an full OB system. I still have some tweaking to do, but overall, this looks like a winner combination.  The H frames turned out pretty good.  These monster drivers are ridiculously inexpensive, although limited in xmax. For listening room use, that should not be a problem. 

 

This combo, I don't think, would be possible if not using an actively crossed system.  The AMT's are way more efficient than the Goldwoods, so had to tweak my amps to match SPL.

 

The symmetrical picture is of the center channel.  The picture with offset drivers is the left main speaker.  The right is the mirror image.

 

This insanity never ends.....I guess that's a good thing.

 

 

 

 

CTRCloseupsm.jpg

LeftCloseupsm.jpg

HTFrontSm.jpg

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I realized after the AMT builds, that I should try to optimize my 2-way speakers by trying to go full dipole vs. using a ported LF cabinet.  After much research I found that an open baffle H frame with dual 18" Goldwood drivers might do the trick.  So, built a prototype and was able to confirm that  in fact, I could go fully dipole and achieve very good full range frequency response. 
 
Yesterday I hooked up the new H frames.  Today, I ran REW and got extremely good results for an full OB system. I still have some tweaking to do, but overall, this looks like a winner combination.  The H frames turned out pretty good.  These monster drivers are ridiculously inexpensive, although limited in xmax. For listening room use, that should not be a problem. 
 
This combo, I don't think, would be possible if not using an actively crossed system.  The AMT's are way more efficient than the Goldwoods, so had to tweak my amps to match SPL.
 
The symmetrical picture is of the center channel.  The picture with offset drivers is the left main speaker.  The right is the mirror image.
 
This insanity never ends.....I guess that's a good thing.
 
 
 
 
CTRCloseupsm.thumb.jpg.74992148769852b9b09e34380dd6f8b3.jpg
LeftCloseupsm.thumb.jpg.b3c00dfce95d847b418b1152c6c12068.jpg
HTFrontSm.jpg.5d7442ab3e727858702285c4eb0498e1.jpg

Wow. Great job. They look really good
How well do you hear the mids and female voices and vocalist ?


Sent from my iPhone using Tapatalk

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2 minutes ago, carlthess40 said:


Wow. Great job. They look really good
How well do you hear the mids and female voices and vocalist ?


Sent from my iPhone using Tapatalk

 

Aha!  That's the all important question.  I have yet to sit down to really listen critically to that level.  Most of today was spent setting timing delay, xover and EQ.  I did listen to a few songs and overall, after a quick listen, they sounded good.  The bass was so nice, plenty of it and more transparent and quick than my ported cabs, which I liked quite a bit as well.

 

I set the xover just below 600hz, which is almost as low as the double stack can go.  Hopefully tomorrow I will get a chance to see how well the double stack AMT integrates with the H frames.  I sure do hope it works out.  I sold the bass bins already, along with the Oris horns.  Buyer wanted them, so that pushed me to this build.  I have been without music for almost two weeks. Can't wait to get back to listening.

 

I'll report back.  The SPL plots look very good at that xover point, so I am hopeful that the AMT can hold its own at that xover point.  That was, in fact, the whole purpose of working on the double stack with wings.

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12 hours ago, Rudy81 said:

I sold the bass bins already, along with the Oris horns.

 

giphy.gif

 

Hopefully the buyer helped manhandle them out of the house??

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35 minutes ago, Thaddeus Smith said:

 

giphy.gif

 

Hopefully the buyer helped manhandle them out of the house??

 

I let gravity do the work to get them downstairs.  After that, craters and freighters handled the rest.

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13 hours ago, Rudy81 said:

I set the xover just below 600hz, which is almost as low as the double stack can go. 

 

I'll report back.  The SPL plots look very good at that xover point, so I am hopeful that the AMT can hold its own at that xover point.  That was, in fact, the whole purpose of working on the double stack with wings.

I have been crossing at 400hz since I have started this project. So far so good. I don’t listen at very high SPL usually though, and my room is small. 
 

I have been experimenting with toe and the angle of the stacks. I raised the back feet of the stack/wings one inch so the stacks are angled towards the listing position. This made a huge difference in the vocal range and really focused the imaging. I reported a few pages back that the sound was more “live” while standing at the listening position. This angle has brought that “live” feel to the seated position. There is now no difference between the standing and seated position and the soundstage begins at a lower point in front of me. I am going to try a few more stack angles and toe adjustments to see if there are any further gains to be had, but I think I am close
 

I did run a few sweeps and adjusted a few PEQs before I did all of the new changes. The output of the heils has changed a little as they continue break in.

 

The sound quality I am getting From this setup at this point is nothing short of incredible. I have been considering building a pair of cornscalas for our living room to put my previous horns, compression drivers and ALK networks to good use. Now I don’t know....

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2 minutes ago, No.4 said:

I have been crossing at 400hz since I have started this project. So far so good. I don’t listen at very high SPL usually though, and my room is small. 
 

I have been experimenting with toe and the angle of the stacks. I raised the back feet of the stack/wings one inch so the stacks are angled towards the listing position. This made a huge difference in the vocal range and really focused the imaging. I reported a few pages back that the sound was more “live” while standing at the listening position. This angle has brought that “live” feel to the seated position. There is now no difference between the standing and seated position and the soundstage begins at a lower point in front of me. I am going to try a few more stack angles and toe adjustments to see if there are any further gains to be had, but I think I am close
 

I did run a few sweeps and adjusted a few PEQs before I did all of the new changes. The output of the heils has changed a little as they continue break in.

 

The sound quality I am getting From this setup at this point is nothing short of incredible. I have been considering building a pair of cornscalas for our living room to put my previous horns, compression drivers and ALK networks to good use. Now I don’t know....

 

What was the original height of the Heil stack relative to your ear position when seated?  I created my bass bins, both ported and new H frames, to have the middle of the Heil stack exactly at seated ear height.  Also, in my testing, I found that a ten degree toe in gives me the best sound. YMMV.

 

 

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Just now, Rudy81 said:

 

What was the original height of the Heil stack relative to your ear position when seated?  I created my bass bins, both ported and new H frames, to have the middle of the Heil stack exactly at seated ear height.  Also, in my testing, I found that a ten degree toe in gives me the best sound. YMMV.

 

 

I was seated right around the middle point of the two heils. Maybe a little lower. The difference now is night and day. My Bass bins are pushed into the corner though, so the back wave of the heils is firing pretty close to wall. I think yours are set up further from the wall so you may be getting more of the dipole effect, not sure. I even tried removing my wall treatments behind the heils, but it did not improve the sound. Quite the opposite.

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Yes, my Heils are much further from the front wall.  They are approximately 4 feet from the front wall and a similar amount from the side walls.  The soundstage is just amazing.  The dipole is in full effect at those distance and with the treatments I have.  I have been working on timing and EQ this morning.  Here are the results for the mains.

 

1 ms. delay

No name crossover at 600hz.

 

I had a heck of a time setting the mic up properly so as to avoid some mic placement anomalies that can be seen  in the group delay.  Best results  were achieved with the mic lower relative to the stack than is necessary to see the true SPL results above 7khz.  Not sure if the mic placement is being affected by the OB configuration, but it took a while to get it correct.  The HF above 7khz is on the level with the rest of the results in actuality.  The directionality of the Heil just doesn't show the actual performance due to where the mic was located. My focus on these REW runs were to get the correct timing and set the xover where I wanted it.

 

 

 

H frame GD.jpg

H frame Spectrogram.jpg

H frame OB SPL.jpg

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3 hours ago, No.4 said:

I was seated right around the middle point of the two heils. Maybe a little lower. The difference now is night and day. My Bass bins are pushed into the corner though, so the back wave of the heils is firing pretty close to wall. I think yours are set up further from the wall so you may be getting more of the dipole effect, not sure. I even tried removing my wall treatments behind the heils, but it did not improve the sound. Quite the opposite.

 

I get the best HF sound while seated.  If I stand up in the room, I definitely lose some high frequency performance. 

 

Did some female vocal listening and thus far, no change from before the LF change.  Vocals are clear and no issues with the crossover point.  I do note a different type of bass performance with the OB H frames vs. the ported box.  Sounds very clean and fast.  I did note during the sweep runs that there is a lot LESS room interference showing up in the REW sweeps.  I am assuming that is due to the dipole cancellation at the speaker plane.  What a nice bonus! 

 

Tonight will be continued testing and some music Blu Rays. 

 

So far, the double AMT stack with an OB low end is sounding superb.  No lack of bass at all with all these 18" drivers....frankly, that surprises me. 

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Has anyone thought about taking this to the extreme ie using a stack of say 10 AMTs to create a line array?  Clearly not cheap but mYbe the result would be worth it?

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18 hours ago, Rudy81 said:

 

I get the best HF sound while seated.  If I stand up in the room, I definitely lose some high frequency performance. 

 

 

I was wondering if you would consider adding a single heil on a speaker stand behind each left and right array to give you better HF coverage at a higher floor to ceiling measurement in the room?  Then again, if you are happy with your listening position, there is no need for this. 

Also curious how your diaphragms are holding up with your lower crossover frequency?  If there is no melting of pleats together, then you are doing well.  

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