I use horn loudspeakers, where a compression dome tweeter operates from the low midrange at 1250 Hz to the highest frequencies we can hear and has much in common with the type of drivers Paul talks about here. However, with horns like mine, the speaker sensitivity is much greater than the type of speakers that utilize “normal” type drivers, such as electrostat’s, planar’s and conventional cone and dome type drivers.
Here’s something crazy. The mass of the FR30 and FR20’s tweeter and midrange diaphragms is less than the air being moved.
Compare that with the heavier mass of even the best diamond-encrusted tweeter in the world, and, at least for me, I experience a moment’s pause.
A pause for two reasons. First, I never thought about air having mass. Second, if all that’s true, what does it mean for the sound of heavier-than-air tweeter and midrange technologies? Are their outputs colored by that extra mass?
Of course, the aspen tweeters and midranges are not the only drivers that are lower in mass than the air they move. Most well designed planar or electrostatic drivers have extremely low mass diaphragms, some falling into the same category as the Chris Brunhaver-designed aspen drivers.
I wonder how much of the natural, open, and uncolored upper end of the aspen loudspeakers is due to this head-scratching fact and how much is due to other factors like crossover design, etc. Even the very best exotic metal dome tweeters and midranges sound colored to me.
After focusing the past 40 years of listening to the top end through low-mass planar and ribbon designs, I suppose I’ve answered my own question.
Still, I wonder.