I posted this in my recent update to my Elsinore Speaker build thread, but I felt it warranted it's own post:
The speakers have been assembled for a long time, but I've not done any finishing work on them because I've been have a very, very difficult time getting them to sound good.
I simply could not get the highs to sound right. Even got what sounded like distortion coming through them semi-regularly. I tried everything, from changing amps, upgrading amps, getting a tube preamp, getting a tubed source, getting a BPT 2.5 balanced power conditioner, having a few Felix power conditioner built, and getting Jensen Iso-Max XLR-RCA converters to replace my Cardas XLR-RCA converters (for my DCX, which is XLR only, to/from my other equipment which is all RCA based). Nothing really helped.
Finally, I focused on the tweeter, the Peerless HDS. Maybe they were damaged. Called Madisound, they felt it was very unlikely they were damaged, as those are very robust tweeters. But they commented that they were very, very, very transparent, leaning to analytical and dry sounding. Basically said that they sound almost exactly like the Scan-Speak Revelator 9700's.
I asked if I should upgrade to something like the Scan-Speak 6600 Illuminator, to get good transparency with better sweetness and musicality (even if it cost $220 per tweeter!!) But they said no, a better match for the Peerless HDS mid-woofers I have would be the new SB Acoustics SB29 Ring Radiator tweeter. How often does a company direct you away from the $220 item and advise you get the $50 one instead? Props to Madisound!
I was skeptical that a $50 tweeter would solve my problem and maintain the level of performance I wanted. But I figured for $100 total, I couldn't really lose (and I could resell them if they didn't). They were a perfect size to be a drop in replacement for the HDS tweeters. After a bit of unscrewing and swapping, they were firmly seated in my elsinores.
Right out of the box they sounded far better than the HDS ever did, even after months of tweaking the DCX active crossover. Smooth, musical, detailed, transparent, and very well integrated. I dropped the crossover from 2.3khz to 1.6khz and it just got better and better. It was the HDS tweeters that were causing the poor sound all along.
I've had them in for several days and they are breaking in more and more, and the overall sound continues to improve. I've heard a lot of different tweeters and this is probably the best dome tweeter I've ever heard. It's got a flat response from below 1khz all the way out past 20khz, its off axis performance is excellent, it's detail is exceptional, and it's tonality is beautiful. At $50, it's a screaming bargain. Here's a pic of the tweeter. It looks like the center is pushed in because there is a small pole in the center, under the tweeter dome, that the tweeter attaches to. This is a "dimple" approach to the ring-radiator application, as opposed to the "nipple" approach that Scan Speak and Vifa use.

One other thing to note - the guys that started SB Acoustics were all senior engineers from Scan-Speak, most of whom were responsible for designing the Revelator and Illuminator lines for them. They formed SB Acoustics after Tymphany bought out Scan Speak and Vifa and Peerless. This is their first offering to the market. My opinion is that they are deliberately putting out a tweeter this good and this inexpensive as a way to thumb their nose at Scan Speak and "show off" to the industry how good they are at building speaker drivers.
All I know for sure is that I'm finally getting world class sound in my home again. Thanks again to Madisound for steering me correctly to this gem of a tweeter.