Sooo.. I looked a little closer and the impedance rise starting at 20hz to about 500-600 on my graph looks pretty bad due to the scale. It measures about an ohm over that distance. The factory graph has a similar rise, but only about a half ohm.
My Fs is about 950 or so. The original rs28f had an fs of around 570, but the rst is specd at 710, so I’m not as appalled that it’s a bit high. I was thinking the specd rst fs was 500-600 as well.
Curiosity got the best of me and I used a small butane torch to melt the glue (which worked great by the way) and I backed the cover off about 1/8 to 3/16 of an inch. Pretty much the foam was touching the motor but not compressed. Here is the result:
I remelted it and put it back where it was.
Im gonna run them with a positive attitude I guess. Supposedly Dayton has fixed the issue on new production so no need to rob grandmas jar lids. The tweeter is efficient, large, has copper in the motor, and I’ve never heard anything bad about their sound or in general, other than this fs issue and that they aren’t the originals.
I have no reason to think at this point that they won’t kick ass in this build. To me it’s kinda like when the GTO was re-released in the 2000s and everyone bitched that it was heavy and didn’t look like the old GTO. True statements, but it was still a sweet car!
Fundamental is 95dB just above 1kHz. Go down to the blue line (second order HD) below it. Move to 1.4kHz, and you are at 33dB or so.
Mind you- I usually measure at a meter to 95dB, and see the HD then. You have to get a reasonable reading above the noise of the room you are measuring in.
Here is distortion at 1m, 90-95db or so. Bottom chart is room noise, which is mostly the laptop fan.
Still not bad on the tweeter. The distortion that picks up around 5k is second order and still almost -50db. It should also be noted the tweeter was swept full range with no cap. It never buzzed or complained.
I'm a little surprised/disappointed by the third order distortion on the woofer. That said, I'm not worried about it as others have commented positively about it's sound.
This is where I’m leaving it for the night. I’ll play with it more tomorrow. It would have been nice to been able to cross a little lower and also to keep the z phase within 30deg, but all came at the expense of the fr sum and/or phase alignment. I think this is pretty reasonable though. I was able to get flat power response through the crossover region but at the expense of an on-axis bump.
12 parts, 1400hz LR4/LR6. 4th electrical both ways (not needed for fr on the woofer but for phase alignment and the knee shape). 1st order on the half woofer.
I haven’t gotten much time to listen but I’ve had a little. The upper bass is a little hot and I’m trying to deal with that with stuffing changes so I don’t have to tear back into the crossovers.
Anywho, just wanted to share some initial impressions of the RST28F. Take it for what it’s worth coming from a guy who likes the silkie.. . Also I have never heard the original 28F.
General first impressions: Not lush/soft/warm, but also not harsh. A one word description: Articulate. One phrase: matter of fact. They really nail every note cleanly and to the point. “Micro information” in the recording is present. Cymbals actually sound like cymbals. Aggressive acoustic guitar attack is rip-your-face-off, in a good way. They start to come apart though at really loud volumes with more complex material though. Not in the form of breakup, buzzing, or agony, but they start to sound mushed together and lose their articulation. Details worth mentioning here though are I have them crossed at about 1400 using only a 2nd order electrical and the tweeter inductor is a laminated core, as it was what I had. Both could be contributing factors in the high output issues. Maybe not.
Pros: efficient, price is ok, can cross lowish, smooth response in Visaton guide, Power handling seems plenty fine. Very articulate and accurate sound without being harsh.
Cons: Gets congested with complex materials at (relatively unreasonably) high volumes - maybe, see above crossover notes). Not warm or intimate if that’s what your after. Questionable QC considering the first generation issues.
My initial verdict: it’s decent, based on some very specific reasons. It’s clean and articulate. It fills a very specific position in the market. There are lots of tweeters that can handle crossing low, but not many maybe with this level of efficiency and at this price. I’d have no problem using it again if I needed something efficient.
I haven’t had any speaker time lately, tied up on other projects around home.. I still hadn’t resolved the mid bass hump sound. I’ll need to take some measurements on and off axis and see where the issue lies. Lots of good things going on with them, they could just benefit from a better crossover designer than I!
I raised the first woofer inductor from 2 to 2.5 and lowered the cap from 15 to 12.7, and also bumped the .5 way inductor from 3.5 to 4.3 by adding a lighter gauge .8 air core, thus also bumping the series resistance a little. Seems to make a good improvement with only time to do a quick listen. I’m much happier with them.
Joey, to answer your question I think something like this would make a great HT main. Definitely want a sub to fill out the bottom end. The RST in that little guide isn’t honky but does have a slight CD characteristic to it to some extent.
Comments
My Fs is about 950 or so. The original rs28f had an fs of around 570, but the rst is specd at 710, so I’m not as appalled that it’s a bit high. I was thinking the specd rst fs was 500-600 as well.
Curiosity got the best of me and I used a small butane torch to melt the glue (which worked great by the way) and I backed the cover off about 1/8 to 3/16 of an inch. Pretty much the foam was touching the motor but not compressed. Here is the result:
Im gonna run them with a positive attitude I guess. Supposedly Dayton has fixed the issue on new production so no need to rob grandmas jar lids. The tweeter is efficient, large, has copper in the motor, and I’ve never heard anything bad about their sound or in general, other than this fs issue and that they aren’t the originals.
InDIYana Event Website
Wolfy's Photobucket
Things are looking good so far. Here is tweeter distortion on axis at 12". THD is -55 to -60 db from 1400 and up.
Woofer distortion - same test conditions.
Black - on axis @ 18", Blue 90 deg @ 18"
Woofer at 18" thru 45 deg
Mind you- I usually measure at a meter to 95dB, and see the HD then. You have to get a reasonable reading above the noise of the room you are measuring in.
InDIYana Event Website
Wolfy's Photobucket
Here is distortion at 1m, 90-95db or so. Bottom chart is room noise, which is mostly the laptop fan.
Still not bad on the tweeter. The distortion that picks up around 5k is second order and still almost -50db. It should also be noted the tweeter was swept full range with no cap. It never buzzed or complained.
I'm a little surprised/disappointed by the third order distortion on the woofer. That said, I'm not worried about it as others have commented positively about it's sound.
Anywho, just wanted to share some initial impressions of the RST28F. Take it for what it’s worth coming from a guy who likes the silkie..
General first impressions: Not lush/soft/warm, but also not harsh. A one word description: Articulate. One phrase: matter of fact. They really nail every note cleanly and to the point. “Micro information” in the recording is present. Cymbals actually sound like cymbals. Aggressive acoustic guitar attack is rip-your-face-off, in a good way. They start to come apart though at really loud volumes with more complex material though. Not in the form of breakup, buzzing, or agony, but they start to sound mushed together and lose their articulation. Details worth mentioning here though are I have them crossed at about 1400 using only a 2nd order electrical and the tweeter inductor is a laminated core, as it was what I had. Both could be contributing factors in the high output issues. Maybe not.
Pros: efficient, price is ok, can cross lowish, smooth response in Visaton guide, Power handling seems plenty fine. Very articulate and accurate sound without being harsh.
Cons: Gets congested with complex materials at (relatively unreasonably) high volumes - maybe, see above crossover notes). Not warm or intimate if that’s what your after. Questionable QC considering the first generation issues.
My initial verdict: it’s decent, based on some very specific reasons. It’s clean and articulate. It fills a very specific position in the market. There are lots of tweeters that can handle crossing low, but not many maybe with this level of efficiency and at this price. I’d have no problem using it again if I needed something efficient.
Thanks!
Joey, to answer your question I think something like this would make a great HT main. Definitely want a sub to fill out the bottom end. The RST in that little guide isn’t honky but does have a slight CD characteristic to it to some extent.