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In the Forum: Horn-Loaded Speakers
In the Thread: Tweeter for Vitavox S2. High-sensitively ribbons?
Post Subject: "Big" tweeterPosted by Paul S on: 11/5/2006
That's one big tweeter, Romy, and, typically, it was made that big only because they intended for it to go low. I keep wondering about the effects of the extra mass, if nothing else, but also about dispersion and window blind effects at increasing frequency with the large ribbons. These can make the vertical listening axis weird, too, in ways that are hard to predict. I am not surprised that any true HF tweeter - a single tweeter - would do best on axis, and this of course is the idea behind the array. I did not mention it earlier, but the Arum Cantus G2Si ribbon itself is extremly thin and it is also pleated. I have no idea what this "really" means, but it does seem like it would affect directivity, if nothing else. The G2Si does have OK horizontal dispersion - for a HF tweeter -, but not much in the way of vertical dispersion, and this is likely due to the "V tipped on its side with flat top and bottom" shape of the magnet assembly in which the ribbon is suspended. In any case, I have found that at higher frequencies anything the sound wave touches profoundly affects the sound, including its character and presentation. I would not be at all surprised if just messing with that foam you mention changed things a lot.
Good luck with NF SET versus 2nd order HF crossover. It has to help that you have a dedicated HF channel. I can tell you the 2A3s don't do any better with 2nd order HF than they do with bass through low pass, and I can also report that the non-SET SET ML2 just blasts right through that crossover and it does make HF.
You said that NF SET makes the best highs, but is this not like the suspicious "clarity" you spoke of in your remarks about the Cogent, when you put it in terms of OTL? That remark made some dominos fall for me, and I mentally re-visited some disturbing sessions with OTL. I had to admit that SET was similar in that some of its greatest strenths are its limitations, if that is not too confusing. And some of that SET clarity seems to come from a particular lack of traction or power in HF, just as much of the "immediacy" comes from tipped up below HF and no LF.
I am waiting to see if any true ribbon will suit you except on axis. I went to ribbons because of laziness with the Peerless/RTRs, and because I was just plain worn out by all the NOISE from other tweeters. That noise is unbearable when riding along with otherwise-properly-proportioned HF. I have always thought this noise was one of the main reasons why horns were best off axis, and nothing different with HF, except in most cases with off axis HF you lose everything EXCEPT the noise.
Best regards,
Paul SRerurn to Romy the Cat's Site