Scan-Speak D2104/7120 - Can someone explain this?

[Mr Sinister]

Hello all,
I bought these tweeters about a year ago and still haven't used them or tested them (I don't have test gear yet). Since then, I've been learning a lot about speaker design and noticed something I never see on a dome tweeter. It has not one, but two impedance humps. I'm curious as to what's causing the second one. I find it difficult to believe that Scan-Speak would leave some kind of gross internal resonance in the design. Especially since it carries the Revelator name. Whatever the cause, it's obviously part of the design. But still, I'm kind of left scratching my head..

[chrisn]

Maybe it's the double vent they use?

[Mr Sinister]

Yeah.. that would explain it. Good catch.

Edit: That is cool

[a4eaudio]

There is a similar (but maybe a little less extreme) double hump on the manufacturer's spec sheet, so that also suggests that it is a result of the design and not a defective tweeter.

[Mr Sinister]

There is a similar (but maybe a little less extreme) double hump on the manufacturer's spec sheet, so that also suggests that it is a result of the design and not a defective tweeter.

Right.. which was why I posted the graphs and said "Whatever the cause, it's obviously part of the design" :p

It did make me look through their catalogue though and it turns out their old classic 3/4 inch domes are dual chamber as well, and have the corresponding impedance humps.

[a4eaudio]

Oops...I didn't even click on the first thumbnail since it was tiny on my phone and I saw a sketchy green banner and person's face.

[Mr Sinister]

Lol.. all good