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The new RST28F-4 tweeters???

PWRRYDPWRRYD
in Announcements
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.
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Comments

  • KornbreadKornbread
    I've got 4 of them laying around from the last sale.  Now you got me worried. 
  • jhollanderjhollander
    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, btw forum has decided I don't get emails
  • jr@macjr@mac
    Yep, saw that too in my quad. RIP RS28.
    I have a signature.
  • jr@macjr@mac
    It's 2019, no need for 90's Morel level of poor tweeter chamber design. 
    rjj45
    I have a signature.
  • PWRRYDPWRRYD
    I've never broken in a tweeter before.  I'll run some sine sweeps through them and see if it makes any improvement.
  • dcibeldcibel
    edited March 2019
    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.
    I'm not deaf, I'm just not listening. https://discord.gg/h5SuNKDJfx
  • PWRRYDPWRRYD
    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?



  • PWRRYDPWRRYD
    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.
  • Tom_STom_S
    Mine don't look too bad - seems I got lucky.
  • jr@macjr@mac
    I love how PE calls these PoI tweets an upgrade over the Usher originals.
    I have a signature.
  • GowaGowa
    I'm happy that I went with the SB SB26STAC-C000-4 over the Dayton now.
    rjj45
  • dcibeldcibel
    PWRRYD, send yours back, they no good.




    I'm not deaf, I'm just not listening. https://discord.gg/h5SuNKDJfx
  • dynamodynamo
    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.
  • PWRRYDPWRRYD
    I'll be calling PE customer service first thing tomorrow morning.
  • dcibeldcibel
    edited March 2019
    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.
    I'm not deaf, I'm just not listening. https://discord.gg/h5SuNKDJfx
  • jr@macjr@mac
    Come on...
    I have a signature.
  • PWRRYDPWRRYD
    PE gave me a RA number to return them and then will send me a new pair.
  • Tom_STom_S
    I hope you end up getting a good pair in the end. Maybe this will cause them to pay a little attention to QC.
  • GowaGowa
    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.
  • jhollanderjhollander
    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, btw forum has decided I don't get emails
  • JasonPJasonP
    Gowa said:
    I'm happy that I went with the SB SB26STAC-C000-4 over the Dayton now.
    Now if you had gone with the SB26ADC-C000-4 :)

    Mitchell_Cote
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • GowaGowa
    Ya, it's strange that tweeter is not used more.
  • PWRRYDPWRRYD
    I received the replacement pair today.  I think they just sent me back the same exact pair I returned.  The two impedance curves lay directly over the first pair.

    Funny thing is I just received an email inviting me to write a review about these tweeters.
  • GowaGowa
     :o 
  • Tom_STom_S
    PWRRYD said:
    I received the replacement pair today.  I think they just sent me back the same exact pair I returned.  The two impedance curves lay directly over the first pair.

    Funny thing is I just received an email inviting me to write a review about these tweeters.
    Well, they asked for your opinion... :#
    Gowa
  • WolfWolf
    Wow- that's a lot of nerve returning the same bad units. I'd call them again.

    InDIYana Event Website

  • Ed_PerkinsEd_Perkins
    edited March 2019
    Maybe they were shooting for an April 1st delivery  :p
  • D1PP1ND1PP1N
    Ive not been happy with PE customer service from my experience a few years ago. Hope they take care of it. 
  • PWRRYDPWRRYD
    I sent a very professional email to tech@parts-expess.com complete with my invoice numbers and screen shots of the DATS impedance measurements of both pairs.  That was only mid afternoon today.  Hopefully they will respond soon. 
  • kennykkennyk
    PWRRYD said:
    Funny thing is I just received an email inviting me to write a review about these tweeters.
    They asked to rate speakers that are on backorder. 🤣
    ............. could you hum a few bars.
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