Hi Mige,
Your measurements looks very interesting.
How do you attach the waveguides to the AMT? And would something like Neo PDR3 work?
Any pics would be much appreciated
Would mounting something like this back to back reasonable?
Your measurements looks very interesting.
How do you attach the waveguides to the AMT? And would something like Neo PDR3 work?
Any pics would be much appreciated
Would mounting something like this back to back reasonable?
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
plug your AMT , electrostat or NEO8 magnetostat (or any other planar speaker suitable for dipole operation) put a bottom and a top plate and you are ready for lift off
Michael
I knew that would come up sooner or later.mige0 said:An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
plug your AMT , electrostat or NEO8 magnetostat (or any other planar speaker suitable for dipole operation) put a bottom and a top plate and you are ready for lift off
Michael
Hello Mikael,
as I told you using such quasicylindrical waves horn result in some diffraction at the horizontal edges of the mouth.
Eventually in order to reduce the effect of those diffraction you may use the idea expressed by Thend (a French audiophile having a strong education in acoustics):
http://thend.chez-alice.fr/Audio/Media/transparent.gif
(the horn is seen in transparency)
http://thend.chez-alice.fr/Audio/2_voies_de_course.html
The idea is taken from the Northrop Grumman Stealth bomber,
http://en.wikipedia.org/wiki/B-2_Spirit
Best regards rfom Paris, France
Jean-Michel Le Cléac'h
as I told you using such quasicylindrical waves horn result in some diffraction at the horizontal edges of the mouth.
Eventually in order to reduce the effect of those diffraction you may use the idea expressed by Thend (a French audiophile having a strong education in acoustics):
http://thend.chez-alice.fr/Audio/Media/transparent.gif
(the horn is seen in transparency)
http://thend.chez-alice.fr/Audio/2_voies_de_course.html
The idea is taken from the Northrop Grumman Stealth bomber,
http://en.wikipedia.org/wiki/B-2_Spirit
Best regards rfom Paris, France
Jean-Michel Le Cléac'h
mige0 said:
Hello Jean-Michel ,Jmmlc said:
That analogy is totally different from what stealth aircraft shape indends, and is misleading. Although such shape will reduce the diffraction as intended, it really more closly resembles baffle edge diffraction reduction design mthods and theory.
The stealth aircraft shape is to concentrate reflection and diffraction in a different direction so that waves will not return to the radar.
Rudolf said:
A Torus, yes, but its not OS profile. A torus is a seperable coordinate and so it will have an exact solution. In all other cases that I have looked at, when this occurs, the diffraction is minimum. This is exactly why I would look at a torus for an OB if I were to do one.
Get an old truck inner-tube and use it to make a mold!!
soongsc said:
Soongsc
Its both actually. The diffraction and reflection are reduced AND they are sent in non-return directions. Either effect alone is not nearly as effective.
Will there be substantial vertical lobing from using a 100mm source and an even larger horn? It seems like the distance between drivers would become significant. Or do people not consider that an issue?
On the other hand, using a horn might make it easier to get the acoustic centers aligned wrt the baffle.
Michael and Jean-Michel, thanks for your work!
On the other hand, using a horn might make it easier to get the acoustic centers aligned wrt the baffle.
Michael and Jean-Michel, thanks for your work!
Thanks Jean-Michel !
Yes I already was thinking about that when building my prototype.
We always will have to deal with diffraction issues whatever route we take. As for the current double hemisphere horn I'm pretty happy that there are no severe irregularities I can see or hear so far – hence I take that particular issue cool.
Quick question – what you think is the deep notch at 600Hz – not that I'm concerned – just curious if this happens in standard horn as well
I was pretty much surprised too to find out that nobody else did it any “sooner”
We see all angels to be 90 deg on that war machine.
Put together two mirrors in the same angle and look at it from different directions – seems the explanations given fall short.
Also there is no substantial diffraction for micro wave at such macro structures.
Vertical lobing is (pretty much) always there once you go with non coax / multi way speaker designs.
The AMT's – as any tall (with respect to wave length) planar speakers do not have very broad dispersion in the vertical direction.
So – as for me – I didn't give up too much with putting a “cylinder wave shape ” horn in front.
You mean to put a fat donut around the speaker?
I thought the same line but came to the conclusion that adding well defined directivity give us the extra bonus of additional gain compared to just spreading diffraction over the rounding of the torus.
At some point you end up with creating some cavity anyway - and there we have to ask how to deal with – this you are especially familiar with (honk)...
Michael
Yes I already was thinking about that when building my prototype.
We always will have to deal with diffraction issues whatever route we take. As for the current double hemisphere horn I'm pretty happy that there are no severe irregularities I can see or hear so far – hence I take that particular issue cool.
Quick question – what you think is the deep notch at 600Hz – not that I'm concerned – just curious if this happens in standard horn as well
soongsc said:
I knew that would come up sooner or later.
I was pretty much surprised too to find out that nobody else did it any “sooner”
soongsc said:
We see all angels to be 90 deg on that war machine.
Put together two mirrors in the same angle and look at it from different directions – seems the explanations given fall short.
Also there is no substantial diffraction for micro wave at such macro structures.
cuibono said:
Vertical lobing is (pretty much) always there once you go with non coax / multi way speaker designs.
The AMT's – as any tall (with respect to wave length) planar speakers do not have very broad dispersion in the vertical direction.
So – as for me – I didn't give up too much with putting a “cylinder wave shape ” horn in front.
gedlee said:
You mean to put a fat donut around the speaker?
I thought the same line but came to the conclusion that adding well defined directivity give us the extra bonus of additional gain compared to just spreading diffraction over the rounding of the torus.
At some point you end up with creating some cavity anyway - and there we have to ask how to deal with – this you are especially familiar with (honk)...
Michael
mige0 said:
Thats not quite true - the edges aren't all 90 degrees, in fact the edge angle is not relavent it's the edge orientation that matters. And there are all kinds of small features on an aircraft that diffract. Look at the cockpit edge treatment on a Stealth, and the engine cowling. All are to reduce cross section.
mige0 said:
You mean to put a donut around the speaker?
I thought the same line but came to the conclusion that adding directivity give us the extra bonus of additional gain compared to just spreading diffraction over the rounding of the torus.
At some point you end up with creating some cavity anyway - and there we have to ask how to deal with – this you are especially familiar with (honk)...
Michael
Honk is diffraction and the donut will minimize the diffraction in a dipole configuration.
dipole horn
You seem to have some nice stuff going on there with the AMT Mige0!
I did a dual horn dipole system prototype last year using the w3-871 and cardboard. The tangbands essentially ran fullrange downto a couple of hundred hertz where a small sub was introduced.
I relation to their total cheapness, they sounded nothing but amazing! Definitely think the concept is worth exploring more.
Cheers,
Jon
You seem to have some nice stuff going on there with the AMT Mige0!
I did a dual horn dipole system prototype last year using the w3-871 and cardboard. The tangbands essentially ran fullrange downto a couple of hundred hertz where a small sub was introduced.
I relation to their total cheapness, they sounded nothing but amazing! Definitely think the concept is worth exploring more.
Cheers,
Jon
Hello,
This is the point I was expecting to have one day and I agree because in my view it is also true for me because it's the same thing, it's just a different way of explain.
For my part, I explain that the return wave is canceled by one side across (not just its end) is the same as saying that the diffraction is oriented in a different direction because the waves sent by this edge are in phase in that direction, this is only a matter of directivity.
Where there is no sound there is cancellation of the phase and where the sound is deflected thes waves are in phase for a given edge.
(automatic translator)
mige0 said:An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
plug your AMT, electrostat or NEO8 magnetostat (or any other planar speaker suitable for dipole operation) put a bottom and a top plate and you are ready for lift off
Michael
Really beautiful work, Michael, and the off-axis measurements (not simulations!) are quite impressive. I'll be trying this with with my RAAL ribbons, although they are monopoles thanks to the magnet construction. Just wrap the curve all the way around, instead to the other half - in that event, the curve almost ends up looking like a cardioid pattern.
I'm passing this link on Bjorn Kolbrek, Martin Seddon, John Atwood, Gary Pimm, and Gary Dahl, since it looks like a real breakthrough for ribbon and AMT enthusiasts. All the complaints about lack of dynamic range should be addressed by this topology, since it gives an efficiency (and headroom) boost exactly where it is most needed, in the midband. The smooth control of (horizontal) directivity is just an extra bonus.
I'm getting close. There is a 20KHz peak in the driver which I would like to try and filter out acoustically, otherwise the outer contour seems quite close. I might also try the Kugelwellentrichter expansion to see how it comes out. I am also trying to look into the detail of the impulses. Starting to seem some funny things in there that I can't quite put a finger on yet.mige0 said:
Good stuff Migeo! A friend of mine has enlisted me to refurb a pair of ESS 1B's with the AE TD12M. I've never worked with the AMT so I'm always on the lookout for info.
Do you have a pic you can post of your AMT on this WG? So would the top and bottom wall of this WG be parallel? Are you not concerned with diffraction there, or are you counting on the vertical directivity of the AMT to help you? Or is there no top wall, and the bottom is just the top of the speaker box? Can you post the dimensions and/or formula you used? Given the ESS AMT has the angled faces due to the magnets, how would they mesh with this WG?
BTW not to go too OT, but I had planned on raising the crossover point for my friend's speaker, what else should I consider about the AMT? How does it's dipolar behavior effect tonal balance given a flat on axis response?
Do you have a pic you can post of your AMT on this WG? So would the top and bottom wall of this WG be parallel? Are you not concerned with diffraction there, or are you counting on the vertical directivity of the AMT to help you? Or is there no top wall, and the bottom is just the top of the speaker box? Can you post the dimensions and/or formula you used? Given the ESS AMT has the angled faces due to the magnets, how would they mesh with this WG?
BTW not to go too OT, but I had planned on raising the crossover point for my friend's speaker, what else should I consider about the AMT? How does it's dipolar behavior effect tonal balance given a flat on axis response?