RD-0194 rattles

VSAT88
VSAT88 Posts: 1,056
edited January 2018 in Vintage Speakers
Hi yall. I have had several RD-0194 tweeters I ordered in the last few months that play fine but rattle at a certain frequency. It can be heard quite well when the piano is being played in classical music like Beethoven. I know the obvious answer is to not play Beethoven but I cannot seem to help myself. Seriously, has anyone else ran into this ? Is there a fix ? I am not the only one who mentioned this after I brought it up. xschopp had this to say,

"I posted a reply somewhere here, and another member confirmed my suspicions that the factory RD0194 plastic faceplates have a design flaw at the 4 baffle mount hole interfaces. They are too shallow and can be remedied by adding washers to make up for the difference in seating depth. This will prevent the plastic faceplate from distorting while torquing down to baffle." in this thread .http://forum.polkaudio.com/discussion/168239/a-real-sl-2000-hack-replace-stock-burnt-voice-coils-with-silk-diaphragm-dome/p7

If this is so I wonder what washers to use ? Where should I put them ? would this take the tweeter out of factory spec in some way ??
Where in Alabama ?
«13

Comments

  • F1nut
    F1nut Posts: 46,266
    #10 stainless steel washers, one at each corner.
    Political Correctness'.........defined

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  • Does this apply to the RD0198's also? The plastic surrounding the mount screw holes is shallower that the perimeter of the faceplate.

    I'm "TL-ing" a pair of M5jr+ that had SL-2000's as stock. After a lengthy burn-in of the new XO's and 198's they still seemed way too bright. I tried substituting old SL-2500's and they had the same problem. I reverted one of them to the stock XO and SL-2000 and did a side-by-side. Sure enough, the stock speaker had MUCH better bass/treble balance.

    Finally, I noticed both the SL-2500's and the RD0198's weren't seating the same as the SL-2000 and figured it must be an air leakage problem killing the bass. I took out the stock tweeter gasket and cut two pieces of Armaflex to shape and stuck them to the back of the SL-2500's. I couldn't believe what a crazy huge difference that made. The SL-2500's almost sound too muffled in them now.

    I was going to try the same trick with the RD0198's but glad I read this first. It sounds like maybe I should try washers and the stock gaskets with the 198's? I didn't realize the tweeter faceplate actually contributed to the sound of the tweeter.
  • pitdogg2
    pitdogg2 Posts: 19,455
    plastic bezel flexes more and pulls at the voice coil is my understanding.
  • pitdogg2 wrote: »
    plastic bezel flexes more and pulls at the voice coil is my understanding.

    Interesting... since Armaflex starts out thick I did notice the bezel flexing a bit at mount points as I was tightening it down. I went fairly slow, though not as slow as when Armaflexing MW's (usually do that over a couple of days). Could be that the Armaflex is still settling (this was just over the weekend).

    I guess I'll give the current setup some time and see how the sound evolves, then get some washers for the 198's to see if that does the job without getting them all sticky.
  • audioluvr
    audioluvr Posts: 3,706
    Is this happening on all the RDO series? Not sure why but I haven't noticed any of these symptoms though I was careful to tighten them down incrementally. Are you installing these washers, between the cab and faceplate?
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  • On3s&Z3r0s
    On3s&Z3r0s Posts: 1,011
    edited January 2018
    I've used the RD0194's and 198's before in 2B's and subsequent 2BTL builds (have some in 2BTL's currently). I never noticed it before, but then there's really no comparison between the 2B bass and M5jr bass, so not sure if I would have noticed a little extra brightness or subtle rattle in the upper mid range on the bigger speakers. I could see very slight differences in the tweeter cutout and condition of the gasket making a difference too. In the M5jr, the SL-2000 seems to fit entirely within the tweeter cutout and sit flush on the raw MDF of the baffle. In my case both the SL-2500 and the RD0198 seem to leave just a little lip of plastic riding on top of the surface of the baffle. Plus, the stock gaskets were not minty. Also, I use different mounting hardware depending on the tweeter. SL-2000's get a round or pan head screw that is flat on the underside of the screw head. SL-2500 / RD0198 use an oval or flat head screw that tapers in a V between the head and threads.

    Good question about where the washers go... I was going to try tweeter, washers, gasket, cabinet.
  • pitdogg2
    pitdogg2 Posts: 19,455
    The new tweeters bezel is a softer thinner plastic. The washer goes behind the bezel to take up the space of the thinner bezel and not allow the bezel to be pulled to the cabinet.
    I'm sure it make no difference but I myself would put the washer next to the cabinet gasket on top of it.

    The older tweeters you could torque down pretty good and didn't run into this problem. thicker bezel, stiffer plastic....
  • VSAT88
    VSAT88 Posts: 1,056
    So, I want to make sure I am reading this right. #10 stainless washers on the cab, then the gasket then the tweeter at the holes marked in red, right ? Lead on Pitt , Jess. qmfl5ggtp4r5.jpg
    Where in Alabama ?
  • Viking64
    Viking64 Posts: 5,607
    I think the purpose of the washer would be to make that little rise at the screw hole flush with the outer edge of the tweeter. Then, both surfaces, meaning the washer and the outer edge of the tweeter, would meet the gasket evenly.

    So, you would have: 1) tweeter 2) washer 3) gasket 4) cabinet

    Although it would likely be possible to put the washer against the cabinet, it seems that application might be more prone to air-leakage as the gasket wouldn't be as flat.

    **** it. Just cram the whole shebang full of Mortite. :p
  • xschop
    xschop Posts: 2,036
    A proper thread title would be RD-0194 RESONATES....
    pitdogg2 wrote: »
    The new tweeters bezel is a softer thinner plastic. The washer goes behind the bezel to take up the space of the thinner bezel and not allow the bezel to be pulled to the cabinet.
    I'm sure it make no difference but I myself would put the washer next to the cabinet gasket on top of it.

    The older tweeters you could torque down pretty good and didn't run into this problem. thicker bezel, stiffer plastic....

    Even after the 4 corner shims I would still get a rattle/resonance, yet less often, in those frequences, that you are describing VSAT.

    I put them away and went with another tweeter in my CRS+

    Having dissected a pair 194's, I thought they could benefit from a very thin gasket material between the plastic coil housing and plastic bezel as well as some of your favorite butyl mat on the back-side of the thin plastic bezel frame. If the newer cheaper plastic bezels are of a lower molecular weight plastic, then indeed they would resonate more. I find it interesting that the TL mod attenuates/contours the 198's @5-6khz zone that corresponds to the 194's "rattle".



  • lightman1
    lightman1 Posts: 10,673
    Check for snakes....might have a diamond back in there.....
  • verb
    verb Posts: 9,925
    Thanks @VSAT88 for bringing this up. I have not installed my new tweets yet, but will certainly use your learnings! #10 washer it is! And yes, shout out to @F1nut also!
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  • F1nut
    F1nut Posts: 46,266
    edited January 2018
    VSAT88 wrote: »
    So, I want to make sure I am reading this right. #10 stainless washers on the cab, then the gasket then the tweeter at the holes marked in red, right ? Lead on Pitt , Jess. qmfl5ggtp4r5.jpg

    Bingo

    Epoxy them in place, makes life easier.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • VSAT88
    VSAT88 Posts: 1,056
    xschop wrote: »
    A proper thread title would be RD-0194 RESONATES....
    pitdogg2 wrote: »
    The new tweeters bezel is a softer thinner plastic. The washer goes behind the bezel to take up the space of the thinner bezel and not allow the bezel to be pulled to the cabinet.
    I'm sure it make no difference but I myself would put the washer next to the cabinet gasket on top of it.

    The older tweeters you could torque down pretty good and didn't run into this problem. thicker bezel, stiffer plastic....

    Even after the 4 corner shims I would still get a rattle/resonance, yet less often, in those frequences, that you are describing VSAT.

    I put them away and went with another tweeter in my CRS+

    Having dissected a pair 194's, I thought they could benefit from a very thin gasket material between the plastic coil housing and plastic bezel as well as some of your favorite butyl mat on the back-side of the thin plastic bezel frame. If the newer cheaper plastic bezels are of a lower molecular weight plastic, then indeed they would resonate more. I find it interesting that the TL mod attenuates/contours the 198's @5-6khz zone that corresponds to the 194's "rattle".



    "The plot thickens". Now that I read these posts I recall thatyx4nkcw7rq48.jpg
    I have also had trouble with the plastic breaking on the diaphragm where the terminal is. I thought I was simply being heavy handed however with more looking at the RD and with checking out the SL tweeter closely it seems not. There is nothing behind that part of the plastic on the RD-0194 it kind of hangs there in space with the only support being the plastic itself. After a break I started placing something between the terminal and the bezel to keep this from happening again. I am beginning to wonder. I have called Polk tech support and they have sent me out two replacements in the past. One due to a rattle, one due to the plastic on the terminal breaking. Now I am wondering what all I am going to need to do to continue to use these tweeters. I like the sound but from what I am gathering the build quality especially for Polk Audio standards is not up to par.
    Where in Alabama ?
  • RandyCroissant
    RandyCroissant Posts: 459
    edited January 2018
    I had a similar issue with a RDO-198 one of the terminals easily snapped off. Some super goo fixed it, but in my opinion they seem cheaply made.
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  • xschop wrote: »
    I find it interesting that the TL mod attenuates/contours the 198's @5-6khz zone that corresponds to the 194's "rattle".

    In some applications it does... in the M5jr's I've definitely heard the "rattle" probably at about that frequency and an overall increase in brightness that makes the whole speaker sound unbalanced in favor of the treble end with the 198's. I'm kind of an unreliable witness as I haven't been able to get as scientific about this as others. But, my experience is definitely consistent with the symptoms described.

    Maybe the M5jr does the contour differently? Unless I messed up interpreting the schematics and parts lists, the only difference between the SL-2000 M5jr and the SL-2500 version is the deletion of the polyswitch and the bump from a 12uF to a 13.5uF cap in the tweeter section. Seems different from how the bigger speakers approach the shift to TL-class tweeters.

    Anyway, I'm glad I'm not the only person to have experienced something like this.

    BTW, what everyone's "favorite butyl mat"? Is that Dynamat? I was afraid I was making a mistake putting Armaflex on the back of the bezel. Now we're gonna Dynamat tweeters too? I love this rodeo! :smiley:
  • VSAT88
    VSAT88 Posts: 1,056
    xschop wrote: »
    I find it interesting that the TL mod attenuates/contours the 198's @5-6khz zone that corresponds to the 194's "rattle".

    In some applications it does... in the M5jr's I've definitely heard the "rattle" probably at about that frequency and an overall increase in brightness that makes the whole speaker sound unbalanced in favor of the treble end with the 198's. I'm kind of an unreliable witness as I haven't been able to get as scientific about this as others. But, my experience is definitely consistent with the symptoms described.

    Maybe the M5jr does the contour differently? Unless I messed up interpreting the schematics and parts lists, the only difference between the SL-2000 M5jr and the SL-2500 version is the deletion of the polyswitch and the bump from a 12uF to a 13.5uF cap in the tweeter section. Seems different from how the bigger speakers approach the shift to TL-class tweeters.

    Anyway, I'm glad I'm not the only person to have experienced something like this.

    BTW, what everyone's "favorite butyl mat"? Is that Dynamat? I was afraid I was making a mistake putting Armaflex on the back of the bezel. Now we're gonna Dynamat tweeters too? I love this rodeo! :smiley:

    LOL !
    Where in Alabama ?
  • VSAT88
    VSAT88 Posts: 1,056
    Does the same exact thing after putting in the stainless steel # 10 washers. No change.
    Where in Alabama ?
  • pitdogg2
    pitdogg2 Posts: 19,455
    VSAT88 wrote: »
    Does the same exact thing after putting in the stainless steel # 10 washers. No change.

    hmmm interesting maybe i'm not so quick to jump on the 198's....
  • VSAT88
    VSAT88 Posts: 1,056
    What tweeters are you using now pit ?
    Where in Alabama ?
  • VSAT88
    VSAT88 Posts: 1,056
    Check that. I have never heard SL3000's. Can't comment. RD-0194 and the SL 2500 I have heard plenty. I think I like the RD tweeters better overall but I have had trouble more than once with them as stated before. I put in a brand new RD 0194 just now and I do not hear the same sound from that speaker. The new tweeter without any "mods" is doing well now.
    Where in Alabama ?
  • pitdogg2
    pitdogg2 Posts: 19,455
    I would still put the washers under it just to be sure you're not pulling it down at the corners.
  • VSAT88
    VSAT88 Posts: 1,056
    I think this is the problem. The alignment is off and causing the VC to scrape the magnet. The images are not the best. I used some magnification but still not so hot. Notice the green extra glue in the area to the bottom right. I think that hits something and is causing the VC former to hit something else.0dn4wy4sudvx.jpg
    7qwxfdoxdvnm.jpg
    Where in Alabama ?
  • VSAT88
    VSAT88 Posts: 1,056
    pitdogg2 wrote: »
    I would still put the washers under it just to be sure you're not pulling it down at the corners.

    Done.
    zirbsnd4suul.jpg
    Where in Alabama ?
  • audioluvr
    audioluvr Posts: 3,706
    Viking64 wrote: »
    **** it. Just cram the whole shebang full of Mortite. :p

    Because you know I've already considered that...
    Cambridge Audio 851N Streamer/DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Belles 350A Reference modded with Mundorf Supreme caps
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January.

    by Dr. Sardonicus
  • Went looking and found the other thread that mentions the washers also so figured I'd link to it here... forum.polkaudio.com/discussion/178997/new-rd0-198-do-not-seat-right
  • F1nut
    F1nut Posts: 46,266
    The issue it seems is with the latest batch of RD0194's as I have not seen it mentioned until recently. I don't recall anyone having the issue with the RD0198's.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • pitdogg2
    pitdogg2 Posts: 19,455
    F1nut wrote: »
    The issue it seems is with the latest batch of RD0194's as I have not seen it mentioned until recently. I don't recall anyone having the issue with the RD0198's.

    thanks Jesse
  • VSAT88
    VSAT88 Posts: 1,056
    Went looking and found the other thread that mentions the washers also so figured I'd link to it here... forum.polkaudio.com/discussion/178997/new-rd0-198-do-not-seat-right

    No kidding. I kind of wish I had seen that thread first. That thread was after all the SL 2500 hack thread. Got it now. I am no longer having the problem however the washers we're not what fixed mine. Replaced with another RDO 194, a new one. That is the only way I could fix it. I suppose the other new one I had in there was just bad.
    Where in Alabama ?