Please review the site Rules, Terms of Service, and Privacy Policy at your convenience. Rules, TOS, Privacy
Get familiar with the reaction system: Introducing the Reaction System

The new RST28F-4 tweeters???

I just purchased a pair of the new RST28F-4 tweeters because they are on sale and I happen to have I pair of the Visaton round waveguides I want to use them with.  Right out of the box these are no RS28 tweeters that we use to know and love...

1)  Visual inspection of them, their faceplates are not centered or clocked correctly.  The 4 attachment screws heads are not centered in their counter bores, not even close.

2)  These are the fabric dome version, not the aluminum dome version, yet they have a phase shield.  Why?

3) I did a DATS impedance sweep of them.  They aren't even close to the published curves that show a single well defined impedance peak at Fs.  Both of the tweeters that I got have a double peak Fs curve that peaks at 425 Hz and then again at 1100 Hz, but the peaks are only 5 ohms.  There is another blip at 1500 Hz.  

Anyone else measure a RST28F-4?  Does their .zma measure close to the published curve or are they more like the pair I got and measured?  I'm not going to monkey around with these (i.e. try to center the domes) because I plan to return these as defective.  Just curious if this is just bad luck on my part or if we have truly lost an old go to product.
«134

Comments

  • I've got 4 of them laying around from the last sale.  Now you got me worried. 
  • As soon as they went NLA I think we lost a go-to tweeter.  I'll reserve judgement until after I get to listen to them (I have the Al version).  I think it still takes years of reviews to get the reputation back.

    Sound like you got the ported version  :/ 
     John H, thanks to JP I did get that email
  • Hey Craig , I ran a sweep on the pair of aluminum dome I have. Lets just say they didnt overlay very well. Ill run another sweep later tonight and post what Im talking about. 
  • Yep, saw that too in my quad. RIP RS28.
    I have a signature.
  • Actually , these look better than when I first ran the sweeps. I did let both burn in for a couple hours FWIW. They were all sorts of wonky initially.
  • It's 2019, no need for 90's Morel level of poor tweeter chamber design. 
    rjj45
    I have a signature.
  • I agree 
  • Im half tempted to dissect one 
  • First blush , face plate screws took nothing to take out. No resistance at all
  • Impressed ,there is some heavy felt like , wool maybe in the rear chamber? Maybe some asian pubicles in the mix too ?  Seeing black kinky hairs . It is damped though and nicely done from what I can see. 
  • I've never broken in a tweeter before.  I'll run some sine sweeps through them and see if it makes any improvement.
  • edited March 9
    It's not bad at all, especially given the cost. The impedance bump is reflected in the frequency response, depending on your crossover point and baffle design it may help the final response or make things difficult. The generous pole vent is nice to see, however it looks like there is felt in the back, and a felt pad behind the dome, but nothing in between. Stick some cotton balls in there, couldn't hurt.
    My opinions are 100% factual
  • I don't know what I should do.  Here is the DATS impedance sweep of the pair I got:



    And of course here is a link to Dayton's spec page:

    https://www.parts-express.com/pedocs/specs/275-141--dayton-audio-rst28f-4-specification-sheet.pdf

    I hate to take a chance and screw up me being able to return them. 

    Nick, looking at the Dayton spec page they say this tweeter has ferrofluid.  I can't tell from your pics.  Do your's have ferrofluid?



  • Also Nick (or anyone else) do your's have any clear markings as to which terminal is positive or negative?  Mine only have a sloppy red Sharpie marker swipe on one terminal.
  • Whoa , those dont look right at all Craig , mine were off but not like that .... eeeash . I have a red sharpie marker that indicates + on the terminal. I do not see any film or residue on the coil that would indicate ferrofluid was applied.  Man , that sucks those sweeps are waaaaay off. 
  • Mine don't look too bad - seems I got lucky.
  • I love how PE calls these PoI tweets an upgrade over the Usher originals.
    I have a signature.
  • Note : If someone wanted to test these with some cotton in the pole piece , you will have to peal the felt pad from the top of the motor and glue it back in after the fact. 
  • I'm happy that I went with the SB SB26STAC-C000-4 over the Dayton now.
    rjj45
  • It’s been my experience with PE that they may just let you keep the defective ones instead of them having to pay shipping, so if so you might be able to dissect them to find the problem.
  • I'll be calling PE customer service first thing tomorrow morning.
  • edited March 10
    jr@mac said:
    I love how PE calls these PoI tweets an upgrade over the Usher originals.
    Yeah, those original RS28 never had any consistency issues or little bumps in the impedance...


    I remember back in the day we'd just be happy just to have a motor with copper in it at USD$30 price point.
    My opinions are 100% factual
  • Come on...
    I have a signature.
  • Whoa , those dont look right at all Craig , mine were off but not like that .... eeeash . I have a red sharpie marker that indicates + on the terminal. I do not see any film or residue on the coil that would indicate ferrofluid was applied.  Man , that sucks those sweeps are waaaaay off. 
    I stand corrected , I was for whatever reason thinking ferrofluid would be white in color. I ran my pinky finger across the coil and there is indeed fluid there. 
    dcibel
  • PE gave me a RA number to return them and then will send me a new pair.
  • I hope you end up getting a good pair in the end. Maybe this will cause them to pay a little attention to QC.
  • Tom_S said:
    I hope you end up getting a good pair in the end. Maybe this will cause them to pay a little attention to QC.
    That's where all the cost cutting is.
  • Rush to fill the void by the demise of the RS28.  Kind of sad, but understandable. How do you create something as good with a short deadline?  I still need to spend some time with them in a decent design. I think Chuck has used them so I'd like to hear want he thinks.  I finished a remote design with them and the RS180 but may not get to hear them any time soon.
     John H, thanks to JP I did get that email
Sign In or Register to comment.