Just wondering if anyone has tried stacking Heil AMTs?
They have a strong magnetic field and I'm wondering if that could cause issues between the drivers if they are stacked one on top of the other.
Came across this cool pic of a AMT-6 speaker.
They have the Heils mounted sideways in a horizontal array. Interesting!
Cheers
Lar
They have a strong magnetic field and I'm wondering if that could cause issues between the drivers if they are stacked one on top of the other.
Came across this cool pic of a AMT-6 speaker.
They have the Heils mounted sideways in a horizontal array. Interesting!
Cheers
Lar
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Lar, there may well be a right and a wrong way to stack the Heils with reference to magnetic cancellations, but I don't think this will be as significant as acoustic considerations. Directivity is a function of acoustic size (the ka factor) ka=transducer dimension divided by wavelength (lamda). As frequency is part of the equation the directivity will vary with frequency.
Unlike a dome etc the Heil is acoustically small (fractional ka value) in the horizontal plane up to 20kHz, but in the vertical plane it becomes acoustically larger beyond 4kHz odd and has narrowing directivity. This is of a type where the extreme high frequency level tends to change between sitting down or standing up listening. By stacking Heils this is going to occur from lower frequencies and be more extreme.
In the photo of the horizontally arrayed Heils the vertical pattern will be quite broad, but I would have reservations about the horizontal pattern. It is likely to be rather "fingured" Sorry if I am telling you things you already knew, but acoustic knowledge is a very valuable asset in understanding loudspeakers. I actually own a pair of Heil tweeters and admire many of their attributes, but directivity is not one of them!
Keith
Unlike a dome etc the Heil is acoustically small (fractional ka value) in the horizontal plane up to 20kHz, but in the vertical plane it becomes acoustically larger beyond 4kHz odd and has narrowing directivity. This is of a type where the extreme high frequency level tends to change between sitting down or standing up listening. By stacking Heils this is going to occur from lower frequencies and be more extreme.
In the photo of the horizontally arrayed Heils the vertical pattern will be quite broad, but I would have reservations about the horizontal pattern. It is likely to be rather "fingured" Sorry if I am telling you things you already knew, but acoustic knowledge is a very valuable asset in understanding loudspeakers. I actually own a pair of Heil tweeters and admire many of their attributes, but directivity is not one of them!
Keith
Thanks for your response Keith!
Looking at the way the Heils are arrayed in the AMT-6s made me wonder about a similar set up where the two outside Heils are placed right side up and the inner two on their sides.
Would probably be cancellation issues though.
With di-pole cancellation as an issue I wonder about what some people have stated about improvements to the sound of the Heils made by dampening placed behind them.
Cheers
Larry
Looking at the way the Heils are arrayed in the AMT-6s made me wonder about a similar set up where the two outside Heils are placed right side up and the inner two on their sides.
Would probably be cancellation issues though.
With di-pole cancellation as an issue I wonder about what some people have stated about improvements to the sound of the Heils made by dampening placed behind them.
Cheers
Larry
Lar', My Heils are no longer in use as one of them needs a new diaphragm and I have the Linkwitz Orion dipole speakers. In the final use of the Heils I mounted them in enclosures in the belief that rear radiation was undesirable as it was going to reflect off the wall behind and comb filter with the front radiation. After reading up on acoustics and psycho acoustics I now realise I was mistaken in this belief, as what happens with binaural hearing is completely different to a microphone receiving sound from two sources such as a direct sound and a reflected version.
I think the decision monopole or dipole needs to be made in the context of the entire system design. If the only rear radiation in the system is from the tweeter the diffuse (reverberant) energy in the room is going to be rather "tizzy" (top heavy). Dipole cancellation and how they may behave with dampening behind them are two different subjects. Do you mean dampening on the wall behind the Heils or enclosing them in a box with damping materials added? When we enclose the rear we no longer have dipole operation and hence no dipole loss. www.linkwitzlab.com/ is a good read on dipoles.
In general, where tweeters are concerned "small is beautiful"
Keith
I think the decision monopole or dipole needs to be made in the context of the entire system design. If the only rear radiation in the system is from the tweeter the diffuse (reverberant) energy in the room is going to be rather "tizzy" (top heavy). Dipole cancellation and how they may behave with dampening behind them are two different subjects. Do you mean dampening on the wall behind the Heils or enclosing them in a box with damping materials added? When we enclose the rear we no longer have dipole operation and hence no dipole loss. www.linkwitzlab.com/ is a good read on dipoles.
In general, where tweeters are concerned "small is beautiful"
Keith
You forget the comb filtering effect !... The distance of the center of the sources modifies the radiation pattern and fixes the "new" high frequency cutoff !
Just how does that work?
Also the impedance, etc but I knew they were all safe from lows.
I did them 3 across, in a straight line and curved. It would be hard to keep any kind of imaging and getting good isolation can be a PIA.
The acoustic issues are not worth it. The heil's dispersion basically acts similarly to a short radial horn- narrowing vertical with increasing frequency, and Omni transitioning to directed as the walls begin to matter.
There's not really a good way to apply multiples in practice, IMO. The tall vertical format precludes success with this method.
There's not really a good way to apply multiples in practice, IMO. The tall vertical format precludes success with this method.
I have two rather large Heil AMTs and want to make a center channel for under a large OLED TV. Can't get my mind to think about a center channel after all these years thinking "stereo". I'm going to have to experiment... I have seen some people build "wings" to lengthen the cancellation path, and one guy made extensions of the front "V" that resemble a horn. Lots to ponder.
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