The One and Only Full Range AMT

[c2cthomas]

Originally Posted by RayCtech

listening is great as long as proper equipment are used.

Uh-oh - nooooowwwww I'm in trouble

SWMBO is not going to be happy with me nailing up several layers of sheet rock and MDF onto "her ceiling" - let alone adding to the "electronics stuff".

Congrat's on the response curves - they look pretty nice for "in-room" measurements

[Charcoal]

measurement looks like some wave guide adding efficience in region of lowmids will be usefull?

[RayCtech]

Originally Posted by Charcoal

measurement looks like some wave guide adding efficience in region of lowmids will be usefull?

A wave-guide are designed and will be used when the AMT (as a dipol) will be used as a midrange / tweeter and crossed over at 100 - 300Hz.

The measurement was taken at 75 degrees off-axis in a reflective room, and in a horn enclosure designed for five AMTs.
The four remaining "holes" are not properly acoustically sealed and interferes and give some dB misreading (both plus and minus).
The measured results are only coarse indications of how the AMT operates in general...

StigErik:
I measured the AMT in free air without a baffle and it the drops in level from 1500Hz even if voices still are relatively "good" - much better than expected.

[Charcoal]

when they will be availble for purchase?

[RayCtech]

Originally Posted by Charcoal

when they will be availble for purchase?

Good question...

The AMT have caused much more attention than I had expected and I believe your question need to be answered at a later point of time...

[Charcoal]

I have read a lot of opinions claiming that making AVT big for fullrange causes unacceptable distirsions .. did you manage to vercome that?

Really interested in that but knowing norwegian selfcosts little bit afraid of price))

[RayCtech]

Originally Posted by Charcoal

I have read a lot of opinions claiming that making AVT big for fullrange causes unacceptable distirsions .. did you manage to vercome that?

Really interested in that but knowing norwegian selfcosts little bit afraid of price))

As I designed the AMT for this bandwidth, and used my own variation of the principles of operation and my own implementation after my own calculations and with materials after my own evaluations - I really do not know why other AMTs effectively do not work properly below 1 - 2kHz.

As I only flipped through the patent papers to verify the most basic principles of operation and was not "bothered" by how other AMTs are designed I believe I was having the needed "freedom" to realize my own goals.

The measured distortion with the current builds are perfect down to 300Hz, and from 300Hz and down to 100Hz there are a rise of 5dB, and from 100Hz and down to 20Hz there are a rise of another 10dB in distortion.
This increase in distortion are related to the physical abilities of the AMT and due to the falling SPL level.

To keep the distortion level down to the perfect level at lower frequencies - then 4 AMTs are need to cover the frequencies below 300Hz etc..

[RayCtech]

.

[Charcoal]

even using one crossed over with some array of light weight cone woofers - could be greate design.

[RayCtech]

I expect there will be questions regarding the practical usability of the AMTs.

When only on AMT are used pr. channel with an enclosure or suitable baffle and run with the full frequency spectrum, 65 to 70 dB average and 90dB peak in the listening position are possible without any kind* of distortion or noise.
This are when using a completely DC coupled system.

*meaning I cannot hear any distortion or noise