Yes it vibrates. But not from any mechanical contact.
I mean, the woofers for sure moves some air.
I mean, the woofers for sure moves some air.
OK... would you think it would benefit from a more sturdy design. Probably as the AMT sits in the baffle...
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So finally I managed to get a second membrane ready and mounted in the right speaker.
Measurement from 50 cm, 1/6 octave smoothing:
I changed the PEQ to 4800 Hz, - 4 dB.
I think I now got a good concept with the motor.
The wave guide and most of all the membrane could be improved a lot though.
Especially the folding tool need a complete overhauled.
Measurement from 50 cm, 1/6 octave smoothing:
I changed the PEQ to 4800 Hz, - 4 dB.
I think I now got a good concept with the motor.
The wave guide and most of all the membrane could be improved a lot though.
Especially the folding tool need a complete overhauled.
Looking really good! I'd love to see some measurements of CSD and impulse response. Areas that a AMT should excell in.So finally I managed to get a second membrane ready and mounted in the right speaker.
Measurement from 50 cm, 1/6 octave smoothing:
I changed the PEQ to 4800 Hz, - 4 dB.
I think I now got a good concept with the motor.
The wave guide and most of all the membrane could be improved a lot though.
Especially the folding tool need a complete overhauled.
/Anton
I've tried get a CSD, but the resolution wasn't good enough. But perhaps it was SBS.
I also think that my room isn't quiet enough to do proper impulse response measurement. Anyway, here's the impulse response from the measurements above:
I'm convinced that AMTs is the perfect transducer and the reward is so great that it is not a problem to have patience; I know that it will be excellent.
Can't help you get any, have you tried this?
Looks like it's inverted. Can you zoom in on the first 2 m?I've tried get a CSD, but the resolution wasn't good enough. But perhaps it was SBS.
I also think that my room isn't quiet enough to do proper impulse response measurement. Anyway, here's the impulse response from the measurements above:
Oh, and do you have the phase? Should be possible to get an accurate reading from below 1 kHz with some windowing.
/Anton
I will exhibit my setup at a small DIY gathering in Jönköping, Sweden, the 24th of October.
Practically, only Swedes will have the possibility though.
Practically, only Swedes will have the possibility though.
The new AMT was highly appreciated and I am now convinced that this design is the one to evolve further.
A better folding tool and a better wave guide are candidates for improvements but also the motor can be enhanced; perhaps have the front pole pieces as thin as the back pole pieces.
But then I will have to figure out how to get 64 pieces of N42 neos hold together, right now it is the front pole pieces that holds the motor together.
Thought I'd get rid of the 5 kHz hump by having non-parallel frame sides:
But that did not happen (green is the frame above):
Never mind the high distortion levels in LF; didn't optimize for that.
An externally hosted image should be here but it was not working when we last tested it.
But that did not happen (green is the frame above):
An externally hosted image should be here but it was not working when we last tested it.
Never mind the high distortion levels in LF; didn't optimize for that.
Thinking of scrapping the wave guide and instead go for the full monty, an AMT line array:
An externally hosted image should be here but it was not working when we last tested it.
Two TD15H in the bottom and a 120 cm high AMT Mk IIB in the top.
Total height will be 170 cm. Three or four AMT membranes.
Do you mean one single 120cm tall AMT? That would be something 🙂
OK - now I see - 4 units - still cool project"!
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OK - now I see - 4 units - still cool project"!
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