AMT's are great designs IF you pay some attention to one thing. It is by far best for sound quality if the Diaphragm Former is made, as it usually is in any good design, from a silk material. The Former provides the physical support structure for the diaphragm material. It is meant to be as audibly transparent as possible and in fact has to be in order to do its job without resonating itself and adding its own coloration to the sound. The silk-derived Former is recognizable from its gray/whitish fibrous appearance, fairly semi-opaque or semi-translucent looking, although in some designs this might not be visible until the tweeter is disassembled.
The problem is that some companies that make cheaper ATM's (often Chinese) use Kapton for the Former material. It's visibly a red colored plastic material and is pennies to produce. But, Kapton is not Nearly as audibly transparent as any silk-derived material and will noticeably color the sound, at least up to about 10kHz or so at which point it seems to no longer be resonating...but anything below that point is trouble.
Just avoid anything that advertises using Kapton and look for those ATM's that mention silk and you should be fine. This will bump up the price range your looking in, but it will be the difference between an ATM that lives up to its promise vs one that plainly doesn't.
The problem is that some companies that make cheaper ATM's (often Chinese) use Kapton for the Former material. It's visibly a red colored plastic material and is pennies to produce. But, Kapton is not Nearly as audibly transparent as any silk-derived material and will noticeably color the sound, at least up to about 10kHz or so at which point it seems to no longer be resonating...but anything below that point is trouble.
Just avoid anything that advertises using Kapton and look for those ATM's that mention silk and you should be fine. This will bump up the price range your looking in, but it will be the difference between an ATM that lives up to its promise vs one that plainly doesn't.