SS 9800 XO question

[augerpro]

I have a pair of Onix Rocket 760s with the Vifa XT25. I had read JonM mention that the SS 9800 is generally a drop in replacement, as far as size and XO design. So I bought a pair. After some more reading the DIY bug got me and I put the 9800 replacement idea on the shelf. I'm now gearing up to start building my own speakers and decided I'd at least like hear those 9800s, since it will be some months beffore I actually build my first speakers.

So, ASSUMING the level will be pretty close, impedence will be close, and the Rocket XO is fairly standard (no notch filter, etc.), the only problem I can see is the XO frequency, which is 1750 Hz. This seems pretty low, even for the XT25, which explains why I started to look at other tweeters. I noticed considerable distortion at higher volumes, though I wasn't sure if it was the woofer breakup from being crossed too high or the tweeter from being crossed to low. When I seen it was crossed at 1750 I figured it's probably the tweeter. Does anyone see problem with trying the 9800s even though they are crossed at 1750 Hz?

[ThomasW]

We've used the 9800 as low as 1200Hz with one of Jon's Cauer Elliptical crossovers.

Lacking specific info about the stock XO in the 760 makes it a little difficult to answer your question.

[augerpro]

We've used the 9800 as low as 1200Hz with one of Jon's Cauer Elliptical crossovers.

Lacking specific info about the stock XO in the 760 makes it a little difficult to answer your question.

Thanks Thomas. After I started to read up on speaker design I figured it wasn''t worth the hassle to put the 9800s in the Rockets using the stock XO. But, as you know, winter is settling in here in Denver, and I thought wth I'll throw them in the Rockets just to hear them.

I'll be getting a laptop soon to complete my measurement setup. Then I'll be getting various drivers for a shootout of sorts and building some bookshelves. The winning drivers will be used in my ultimate goal of building some towers to beat my Rockets. But winter is gonna slow that progress down, so I may get bored and pull the XO out of the Rockets and analyze it, maybe even rebuild it for the 9800s if I like what I hear in my informal listening.

[Dennis H]

Heck, yeah. You've got the tweeters so plop 'em in there and see how they sound! Measurements and all that good stuff can come later.

[augerpro]

Heck, yeah. You've got the tweeters so plop 'em in there and see how they sound! Measurements and all that good stuff can come later.

:T


Thomas in your experience does the 9800 exhibit less distortion in the 1750-2500 Hz range than the XT25? I've yet to find a HD measurement for the 9800, and obviously don't have my own setup running yet.

[ThomasW]

I've never used the XT25. I helped a couple friends build designs with them, but I prefer metal domes.

This is from a post Jon made when we were dialing in my Arvo prototypes..

We selected the SS9800 because it's quite compatible electrically with the Vifa XT25 (Vifa and SS are both part of DST) with regards to impedance curve and basic frequency response (to below 1 kHz) and efficiency, but also because it's one of the lowest distortion tweeters on the market, being quite comparable to the SS2905 and Seas Excel tweeters. It's one of the most neutral tweeters I've heard, and though not as efficient as the Td120dx2 Focal, it is happier playing lower.

[augerpro]

Thanks for digging that up Thomas. I read that whole monster thread one night just because it mentioned the 9800. My brain must faded because I don't remember reading that. Funny how I can read books all day long, but if I stare at a computer screen my retention drops after the first hour.

Just one more question (sorry), do you attempt to tame the breakup in metal domes usually? It seems not alot of people do. After I do my woofer shootout I will be doing a tweeter shootout. Since I honestly don't know if I prefer soft or metal domes I figured I'd use some good examples of both. So I'll probably get pair of 9700s at that point. Just wondering if I should do something about thte breakup or leave it.

[ThomasW]

We've never used any filters on the top end of the tweeters