At $350 USD each I won't be stacking - it would be one per side.
ESS Great Heil Air-Motion Transformer | Parts-Express.com
No, I wouldn't think so. I had to go through hell to get my AMT1s. I got 2 pairs, one were totally smashed by the moron shipping them (flat rate box and no packing.... dumb doesn't begin to describe it) and the others were impeccably crated. However! The loose baggie of screws made its way into one of the magnetic gaps and the type of phragms available didn't match so I needed 2 phragms.
After all that, these danged horns better work well! I'm pretty optimistic, they seem intuitively to be an excellent adaptation for these drivers.
Well, I think that the obvious choices would be to either go with a 6.5" or 8" dipole mid and use this as a 1200+ tweet, with a substantial box woofer on the bottom (say below 300-400) or to do a directivity matched 2 way- for the forward plane, and accept the monopole-dipole transition at the crossover. I'll try it a few ways when I get it running. Sadly I run many projects in parallel so this may take a while, though the majority of fabrication is done- I have 7 of the compound cut edge rounds done.
Ahhhhh - one of the age old questions of how low to go with the AMT1 - The results of horn loading is going to change this game a bit (perhaps) so I'll hold off on this topic. I'm sure you have your own ideas about the many issues involved and it's my intention to try and help out and maybe learn a couple of things.
I have considered going this way before but could not find a mid to mate with the AMT1 that I liked - but that gets us into the x'over topic and we just came out of that door.
I'll shut up and leave ya alone and chip in when (and if) I can contribute something constructive.
I guess I am late comming to this thread ... I have a 3 pack of amt1b's. I am using 2 in a mid room position where they work fantastic for music especially. I am thinking of making a center channel incorporated into the stereo cabinet sometime out of the amt.
I also have been toying with the idea of putting in my own magnet cage with super strong neodymium magnets ... That ofcourse is a whole other can of worms.
Cool.
Srinath.
I also have been toying with the idea of putting in my own magnet cage with super strong neodymium magnets ... That ofcourse is a whole other can of worms.
Cool.
Srinath.
Got me thinking
Hey badman,
Your pic got me thinking and that is always dangerous ...
If you put the heil 90 degrees to the way it is in that horn and move it forward you will be reflecting both the front and back waves into the front. The horn of course has to be made of metal but its relatively easy to bend sheet metal into a horn. Then back it with wood I guess.
The dipole actually creates more trouble than it helps IMHO. The tempest which has the smaller heil in a monopole is a easy speaker to toss in anywhere. The dipole amt1b I have just reflects and smears and just makes a mess in my house atleast.
Cool.
Srinath.
Hey badman,
Your pic got me thinking and that is always dangerous ...
If you put the heil 90 degrees to the way it is in that horn and move it forward you will be reflecting both the front and back waves into the front. The horn of course has to be made of metal but its relatively easy to bend sheet metal into a horn. Then back it with wood I guess.
The dipole actually creates more trouble than it helps IMHO. The tempest which has the smaller heil in a monopole is a easy speaker to toss in anywhere. The dipole amt1b I have just reflects and smears and just makes a mess in my house atleast.
Cool.
Srinath.
Hi:
Can you draw a diagram? I'm not sure what you're saying with the orientation. If need be, I can damp the backwave, which may well be better suited to my purpose, but it sounds like you're talking about creating a heil horn with a dual entrance of dissimilar pathlengths.
I'm going to try kerfing the sideboards and wrapping them into place today. The 1/2" panels acting as spacers are only glued in place, and that only by press-fit gluing (which isn't as bad as it sounds, especially if you gapfill with glue after wards). But the 3/4" wrapped side panels ought to substantially increase the strength of the assembly. I'm not decided on whether to use the top deflectors- the dipole cancellation upwards may be the better solution for me.
Can you draw a diagram? I'm not sure what you're saying with the orientation. If need be, I can damp the backwave, which may well be better suited to my purpose, but it sounds like you're talking about creating a heil horn with a dual entrance of dissimilar pathlengths.
I'm going to try kerfing the sideboards and wrapping them into place today. The 1/2" panels acting as spacers are only glued in place, and that only by press-fit gluing (which isn't as bad as it sounds, especially if you gapfill with glue after wards). But the 3/4" wrapped side panels ought to substantially increase the strength of the assembly. I'm not decided on whether to use the top deflectors- the dipole cancellation upwards may be the better solution for me.
In your post #117 the last pic. Turning the amt assembly 90 degrees, so you're looking at the big square end of it, and moving it forward so its closer to you and the Horn shape closes into the back of it will make it a monopole with the front and back waves comming into the front side via the horn.
However, all my issues in my house are with the fact that the amt is a dipole. I am going to do anything basically to make it a monopole without stuffing the back side with a mattress. You probably are trying to do something else. So maybe I am leading you down the wrong path.
Cool.
Srinath.
However, all my issues in my house are with the fact that the amt is a dipole. I am going to do anything basically to make it a monopole without stuffing the back side with a mattress. You probably are trying to do something else. So maybe I am leading you down the wrong path.
Cool.
Srinath.
I don't have the problem with the dipole that you seem to, and I'm well beyond the point of no return on this assembly. Will update as it gets built.
The arrangement you propose is a worst-case scenario, IMO. The cancellation from the 2 sides of the dipole would make this a non-starter, unless I'm still misunderstanding.
But the waves are 180 degrees out of phase. When they encounter you have a cancellation.
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They wont really encounter each other in reality with a horn design like a T350 style horn. They will get spread with maybe a 30-45 degree dispersion angle.
Also they are not 18 degrees out, they are I believe identical just shifted by the width of 1 pleat.
Compression between pleat 1 and 2 in the front wave is a compression between pleat 2 and 3 in the back wave. Atleast I think it is. That is called a dipole if I remember.
The type that is 180 degrees out is a compression wave travelling forward and a rarefaction travelling backward. It probably is the infinity emit style ribbon where the ribbon moves toward you. They call them bipoles if I remember.
I think. I have to check to be sure. Pleats move toward each other, but alternate pleats move in opposite directions. 1 and 2 getting closer = 2 and 3 separating, and 3 and 4 together etc ...
Cool.
Srinath.
Also they are not 18 degrees out, they are I believe identical just shifted by the width of 1 pleat.
Compression between pleat 1 and 2 in the front wave is a compression between pleat 2 and 3 in the back wave. Atleast I think it is. That is called a dipole if I remember.
The type that is 180 degrees out is a compression wave travelling forward and a rarefaction travelling backward. It probably is the infinity emit style ribbon where the ribbon moves toward you. They call them bipoles if I remember.
I think. I have to check to be sure. Pleats move toward each other, but alternate pleats move in opposite directions. 1 and 2 getting closer = 2 and 3 separating, and 3 and 4 together etc ...
Cool.
Srinath.
Please knock up a diagram of what you're describing, I think we're having a communication breakdown.
However, you're wrong on the dipole operation. The AMT works such that when pleat 1 opens, pleat 2 closes, pleat three opens, and so forth. So when a positive pressure is created in front of the ribbon, the opening pleats on the back side create a rarefaction. They are indeed 180 degrees out of phase, just like a ribbon without a rear chamber, but the pressure/rarefaction are created by the bellows motion rather than an in-out motion, hence AMT.
Yea That 180 degrees is correct, it will be out 180.
The coil is in the wall of the pleat per se, not at the bottom, I keep getting that confused.
That means the left speaker needs to be built 1 way and the right its mirror image.
I will try to put a drawing up. The other thought I had was, just because it wont cancel each other doesn't mean it would sound good. Horns are not meant to have sound hit the wall @ a 30-60 degree angle, In a way horns are there to prevent sound from dispering into a wider and larger spread out field. Without that horn, you would get more response way off axis and a lot less response on axis. Anyway I'll try to get a drawing done and post it.
Cool.
Srinath.
The coil is in the wall of the pleat per se, not at the bottom, I keep getting that confused.
That means the left speaker needs to be built 1 way and the right its mirror image.
I will try to put a drawing up. The other thought I had was, just because it wont cancel each other doesn't mean it would sound good. Horns are not meant to have sound hit the wall @ a 30-60 degree angle, In a way horns are there to prevent sound from dispering into a wider and larger spread out field. Without that horn, you would get more response way off axis and a lot less response on axis. Anyway I'll try to get a drawing done and post it.
Cool.
Srinath.
Now you're talking L/R cancellation... the cancellation we're concerned with is the front vs. rear wave of the heil. I'll wait for your drawing!
Best,
b
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