Anyone try Townshend Super Tweeters?

Jtgofish. Hmmmmmmm.... .5uf or 1uf cap? Are you using an inductor in series with the cap?

I've been using Tonian Supertweeters (ribbon) with Harbeth C7s for a number of months. They've added openess, air, sparkle(the good kind - like finer musical nuance) along with extended highs. Tonian matched them for my speakers specifially and sent along extra resistors to adjust the output level if needed - didn't have to. I've also, for fun, tried them with Spendor 3/5s and got the same result. I'd have to say that anyone with Harbeths, Spendors, or (based on my listening in stores only) some models of Sonus Fabers would really like these tweeters.

I can't say whether they'd be useful with speakers that claim to go to 25khz anyway but Tonian claims they have output to 40,000hz. Tonian offers a home trial but they are expensive. However, I find them indespensible.

Sirspeedy- I'm not sure it's overkill, I'm just wary of the cost-benefit.
Yr room treatment obviously addresses reflections (you mention "glare"). By adding a s-tweet you'll be adding HF sp on axis & (assuming a ~30degrees dispersion) and some reverberant sound as well (you'll effectively overcome part of the room treatment): so, you might perceive more "air" and HF harmonics will be more pronounced, even at low volumes. From yr description, you don't need a s-tweet for high volume listening.

This may be useful for cd as there typical response peters out after 10kHz or so -- the energy level falls.

TO put things plainly, the advantage of a s-tweet is that its response limit is so high up that the audible HF are well within its linear region. The disadvantage is that it won't play as low as a regular tweet... Most spkrs start dropping in room, around 10kHz or so, & a s-tweet will cover +10Khz easily (and that's audible).
Best thing would be to borrow one -- possible? Try at low AND high spl. Cheers

Gregm...What's with this 10 KHz roll off with CDs and speakers? My disc player measures flat to the top of my spectrum analyser,20 KHz, and, before equalization, my Maggie MG1.6QR only falls off in the highest 1/6 octave band (just below 20 KHz). It is true that music, whether on LP or CD, typically has rolled-off energy above about 10 KHz.

I know that my ability to hear pure sine wave signals quits around 14KHz or so, but I can still "hear" the effect of tweeters and supertweeters much higher than this. I think this is because a music signal generally has waveforms that are as steep as a sine wave at 20KHz or higher, and the ear (at least mine) senses the steepness of the waveform.

Eldartford, I don;t doubt yr disc player measures flat on a sine & yr maggies likewise. Try (if feasible) to measure response (FR + PR) on a musical signal at listening position in room & compare to what's on the storage medium -- say the cd in this case.
As to your ears, they are possibly "sensing" a combination two things. 1) that there is info beyond 14kHz (which is what you note, so I'll take yr word for it), because, 2) there is no steep/sudden barrier/filter/drop over 14kHz -- i.e. the sound continues even if yr accuity drops.

People listening to linear extended HF reproduction find the sound "softer" than when there is a sharp roll off within the audible range. Cheers