Joachim,
thanks for taking that effort too!
Your 0, 45 and 90° measurements suggest an impressively constant directivity of the "baffled" AMT from 6-13 kHz. Sadly the Mundorf AMT flyer stops at 30°. If you could measure the pure AMT too for comparison, that could shed some light on what SL really achieved with his baffle shape.
Rudolf
thanks for taking that effort too!
Your 0, 45 and 90° measurements suggest an impressively constant directivity of the "baffled" AMT from 6-13 kHz. Sadly the Mundorf AMT flyer stops at 30°. If you could measure the pure AMT too for comparison, that could shed some light on what SL really achieved with his baffle shape.
Rudolf
I measured in ca. 50cm.
4th picture red is on axis and yellow is 45° frontal.
It is hard to keep the measurement distance constant so the sensitivities may not match to the last dB.
I will repeat that measurement and hold the distance constant as much as i can.
Also 15°, 30° and 60°.
Between 3kHz and 5kHz linearity is a bit better off axis.
I do not know if i can improve that by changing the shape of the baffle.
On the other hand i will use the AMT only over 7kHz and there it looks fine.
The null in the area of interest is ca. 10dB.
That is aprox. what Kreskovsky gets in the older NAO that has the B&G magnetostat.
The new NAO has a stronger null and i asume the LX521 is better too.
I think that comes because is both cases the tweeters are rather small.
The AMT is wider so the null is not that strong.
Yes, the AMT starts to beam over 13kHz.
4th picture red is on axis and yellow is 45° frontal.
It is hard to keep the measurement distance constant so the sensitivities may not match to the last dB.
I will repeat that measurement and hold the distance constant as much as i can.
Also 15°, 30° and 60°.
Between 3kHz and 5kHz linearity is a bit better off axis.
I do not know if i can improve that by changing the shape of the baffle.
On the other hand i will use the AMT only over 7kHz and there it looks fine.
The null in the area of interest is ca. 10dB.
That is aprox. what Kreskovsky gets in the older NAO that has the B&G magnetostat.
The new NAO has a stronger null and i asume the LX521 is better too.
I think that comes because is both cases the tweeters are rather small.
The AMT is wider so the null is not that strong.
Yes, the AMT starts to beam over 13kHz.
Joachim - care to comment on the differences between the Linkwitz LX521 and the Kalasan design you recently completed and which speaker you personally prefer? I have built Linkwitz's Phoenix many years ago and can only assume the LX521 is much better. But I have not heard it (nor the Kalasan for that matter since you just designed it!). Thanks and looking forward to this thread.
gab
gab
They are very different animals.
The LX521 needs space to breath and is active so cost is considerable higher.
The Kalasan is as good a monitor as i can make it so it depends on the budged and the space you have.
Whereas the LX521 is a real enthusiast system that nedds a dedicated listening space or a tollerant family the Kalasan is much smaller and more tollerant to system and setup i think.
Coulor me blind when i do not go in detail about the sound differences.
First i designed the Kalasan so i think it is great
Second i have not heard them in the same space.
I will of cause put my version in my sytem asap.
DSP and DA converters made for my version are on the way.
The LX521 needs space to breath and is active so cost is considerable higher.
The Kalasan is as good a monitor as i can make it so it depends on the budged and the space you have.
Whereas the LX521 is a real enthusiast system that nedds a dedicated listening space or a tollerant family the Kalasan is much smaller and more tollerant to system and setup i think.
Coulor me blind when i do not go in detail about the sound differences.
First i designed the Kalasan so i think it is great
Second i have not heard them in the same space.
I will of cause put my version in my sytem asap.
DSP and DA converters made for my version are on the way.
Inglorious Bastard
Hey Joachim,
I apologize if this is the wrong place for this post. And if it's a problem feel free to have a moderator delete it.
I read the first couple posts and have thought about it for a few days. I realized I have a pair of HEIL Elite amt's gathering dust upstairs along with that symmetry crossover we talked about a few years ago. And I thought with the addition of the mid-woofer I could build a bastardized version. I intend to use the same SEAS 8" Siegfried used crossed to the Heil at 1500hz. I was going to use a 2nd order Linkwitz-Riley. But you say you used just a 1st order passive between the upper and lower mids? I'm hoping the Heil can stretch your amt model and make it a three way.
Stack that on a 12" sealed woofer enclosure for now and maybe when I have the cash add Siegfried's bass arrangement. The Symmetry is very adjustable for the crossover between the bass and the upper drivers. From the 8" frequency curves it looks like 100hz might be a good starting point.
Kevin
Hey Joachim,
I apologize if this is the wrong place for this post. And if it's a problem feel free to have a moderator delete it.
I read the first couple posts and have thought about it for a few days. I realized I have a pair of HEIL Elite amt's gathering dust upstairs along with that symmetry crossover we talked about a few years ago. And I thought with the addition of the mid-woofer I could build a bastardized version. I intend to use the same SEAS 8" Siegfried used crossed to the Heil at 1500hz. I was going to use a 2nd order Linkwitz-Riley. But you say you used just a 1st order passive between the upper and lower mids? I'm hoping the Heil can stretch your amt model and make it a three way.
Stack that on a 12" sealed woofer enclosure for now and maybe when I have the cash add Siegfried's bass arrangement. The Symmetry is very adjustable for the crossover between the bass and the upper drivers. From the 8" frequency curves it looks like 100hz might be a good starting point.
Kevin
equipment improves > many recordings disappoint
That can happen all too often. especially if you like pop (rock) music
To deal with this, possibly:
A second set of speakers, less detailed But needs space and $/€, WAF?
A less detailed amp, possibly tube. Most $/€
Tone controls or EQ Simple & cheap, tuneable & can be taken out of circuit
A friend at a holiday house had an old pair of speakers. Playing pretty ordinary sounding 50s-60s pop, it often struck me how very enjoyable it sounded.
Some of it was
But more than anything else, I think it was a moderate mid bass hump, adding a nice degree of warmth and added power.
I wish I had their measurements! Plus 1.5 dB, over 80-160 Hz??
This could be a worthwhile separate thread. But for now any thoughts guys?
That can happen all too often. especially if you like pop (rock) music
To deal with this, possibly:
A second set of speakers, less detailed But needs space and $/€, WAF?
A less detailed amp, possibly tube. Most $/€
Tone controls or EQ Simple & cheap, tuneable & can be taken out of circuit
A friend at a holiday house had an old pair of speakers. Playing pretty ordinary sounding 50s-60s pop, it often struck me how very enjoyable it sounded.
Some of it was
But more than anything else, I think it was a moderate mid bass hump, adding a nice degree of warmth and added power.
I wish I had their measurements! Plus 1.5 dB, over 80-160 Hz??
This could be a worthwhile separate thread. But for now any thoughts guys?
Darkheart,
Have you considered the force cancelation value of putting two 15" woofers in a W-frame dipole, instead of the U-frames you are planning? I am only thinking about physical size and dipole efficiency. For proper performance, a U-frame must be deep and cleverly stuffed to obtain good cardiod polar response. I have never built a U-frame, so I cannot judge the polar effect sound difference from the W-frame.
I posted the dual 12" H-frame alternative for a LX521 clone because it provides greater bass performance in the same max-limit usable height as the dual 10" with its stand. The European engineers who experimented with spring/rubberband mounted mid-bass dipole baffles posted measurements proving very little physical movement. A counterforce W-frame could have low vibrations to allow a simple mid-tweet baffle stand.
I think the polar response from an AMT tweeter without any waveguides is necessary to blend with the upper-midrange mini-baffle dipole polars.
Yes, and likely.
SL is certainly right to say that relatively small changes in it can make quite big a difference.
Yes, I have considered W-frame an H-frame, but I prefer a U-frame and probably will try some stuffing to get cardioid-like response. I think I will make a bridge over the U-frame.
I think that waveguide is necessary to blend with an 8-inch driver. It will not be a "mini-baffle".
I decided on the woofer. From another project i have 2 Tymphany Lat´s :http://www.tymphany.com/files/resources/dlat/LAT500-002.pdf
Somehow they work on the same priciple as an AMT.
Heil had a speaker, Transar, where i saw first that an AMT woofer can be made.
Unfortunately this driver is not made any more.
One can always use the LX woofer instead or other solutions, M, H, U frame and such.
I will put the Lats in a simple H frame. That is the most puristic i think.
Somehow they work on the same priciple as an AMT.
Heil had a speaker, Transar, where i saw first that an AMT woofer can be made.
Unfortunately this driver is not made any more.
One can always use the LX woofer instead or other solutions, M, H, U frame and such.
I will put the Lats in a simple H frame. That is the most puristic i think.
At the end of the 70th i heard the Transar. Dr.Heil was also there making his Cherry joke.
I think they look very modern and exiting, even today :
http://cdn.avsforum.com/1/18/183175cb_vbattach48702.jpeg
I think they look very modern and exiting, even today :
http://cdn.avsforum.com/1/18/183175cb_vbattach48702.jpeg
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