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.
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.