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The Defiants - InDIYana 2019 Build

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  • jhollander
    replied
    Might try tightening up the gating. It looks like there's a blip at 4.2 ms and your gating is at 5.? ms.

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  • KEtheredge87
    replied
    Quick update and question Gents... XO measurement and testing is finally underway. So far I've got something that sounds passable, but will still get some attention and attempts to better the result. One odd result I am seeing and I don't quite understand is an apparent suckout on my tweeter right around 1kHz. The blue line in the OmniMic data is my good RST28F with Visaton WG148R waveguide with no crossover applied. The red line is my XO measurement for the HF section as shown in the Xsim screenshot. I've never used a waveguide before... but that missing 10 dB doesn't feel right to me.

    Anyone ever seen that before?
    Attached Files

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  • KEtheredge87
    replied
    Originally posted by jhollander View Post
    Are custom made tweeters allowed? Actually that's pretty amazing service. Lots of good stuff (and people) coming to Indy.
    Ya know John, I sure hope so! Although Ben's rules say a competitor must list the cost of all modifications that were made to the driver... I'm not quite sure how to tally this one up!

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  • jhollander
    replied
    Are custom made tweeters allowed? Actually that's pretty amazing service. Lots of good stuff (and people) coming to Indy.

    Leave a comment:


  • KEtheredge87
    replied
    Thanks johnnyrichards , I saw those other posts too. While quality control issues are never fun, there is a happy end to this little emergency. I started a post on the Facebook group that many here frequent to see if more folks had some knowledge that could help. The guys at PE noticed and contacted me to give me some details and offer a solution. They said an official post from PE is supposed to come tomorrow to explain in more detail, but the gist of the issue is this:

    The manufacturing house that makes the RST28F and RST28A tweeters started putting the wrong foam down inside the RST28F tweeters without telling PE there was a change. Unfortunately... in the engineering world, these things happen, and nobody likes it! The design of the motor does not allow us to replace that foam without damaging the motor, so there's no way to fix those incorrectly made motors. PE is having new stock sent via air freight... but they won't be available in time for InDIYana.

    Lucky for me / us... While the motor design is the same between both versions of the tweeter, only the RST28F's seem to have been incorrectly made. PE is going to assemble a good motor from the Al tweeter with a fabric dome, and send it my way. They're even going as far to closely match the impedance signature of this replacement to the ZMA file I have of my good tweeter outside of the waveguide.

    I'm glad to see PE is taking care of their customer base. Quality spills suck... there's no debating that. But I find that what a company does in the wake of a spill is infinitely more important, and Parts Express went out of their way to help me today. I don't expect any special treatment... and I didn't ask for any... but they were there all the same. Thank you very much, PE!

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  • johnnyrichards
    replied
    He was trying to share that there was a batch of the RS28 that are bad, and a lot of them made it into the wild. There is some data collected at another forum demonstrating it. PE seems to be addressing it

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  • KEtheredge87
    replied
    Originally posted by PWR RYD View Post
    My post was "unapproved"? I guess facts hurt.
    Hey Craig, not sure if the forums are playing games with us... I didn't see anything from you except the quote above. What were you trying to share with me?

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  • PWR RYD
    replied
    My post was "unapproved"? I guess facts hurt.

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  • PWR RYD
    replied
    I bought a pair thats' impedance sweep measured exactly like that Keith. So PE let me return them and they sent me a replacement pair. Awesoeme customer service department! Unfortunately the second pair measured just as defective ​​​​​​ I sent them an email with the .zma files attached. They kindly replied that they investigated and found more in their stock like that and they refunded my credit card, again great customer service from PE The next day I noticed that the RST28F-4 "in stock" changed to "due in 6-14-19". Maybe the entire last batch from their new supplier was defective?

    Leave a comment:


  • KEtheredge87
    replied
    Originally posted by Billet View Post
    Do the two tweeters actually sound different if you connect your crossover? The impedance curve reminds me of a ported woofer, maybe there is an air leak behind the dome?
    Hey Billet, That's a good question., I haven't actually built the crossover yet, so I may need to try it anyway once that's available.

    I did take some OmniMic FRD measurements just to make sure my assembly of the tweeter into the waveguide was consistent. I even used a 1/16" thick EPDM rubber gasket to make sure I sealed off the area between the tweeter's dome carrier and the waveguide. The measurements show a big difference between 500 Hz and 1200 Hz, and some small discrepancies across the higher ranges that I could have otherwise dismissed as normal part-to-part variation. I would prefer these drivers measuring nearly identical across the whole frequency range, just to make sure I don't get any strange cancellations or other oddities showing up in my crossover results from cabinet to cabinet.

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  • Billet
    replied
    Do the two tweeters actually sound different if you connect your crossover? The impedance curve reminds me of a ported woofer, maybe there is an air leak behind the dome?

    Leave a comment:


  • KEtheredge87
    replied
    Hello Everyone,

    Lots of progress to report, but not a lot of time to type it out in detail so I'll be kinda quick today.

    1) Cabinets are DONE!!!!! I've got a little bit of bling to add before the show, but for now I'm focused on XO design and measurements.
    2) Grilles are started. First time I've ever made a grille for anything, but that RST28 fabric dome is sitting in the waveguide like the Eye of Sauron. It's just BEGGING for a little kid to poke it in!
    3) Port tuning was almost spot-on vs. BassBox Pro: Model said 38.97 Hz... DATS measurements said 37.68 Hz for both cabinets. Modeled within 1.5 Hz... I'll take it!

    This next one really bummed me when I figured it out...
    4) One of my RST28F-4 tweeters was broken straight from the factory. Fs measurements / impedance sweep is all wrong. Check out that screenshot below. I've contacted PE's customer service line, but the website says they're out of stock until June.

    I already have one alternate means of replacing this one in time for InDIYana (Thanks xmax !) Just in-case something doesn't work out there... does anyone else have a spare RST28F-4 that they're willing to sell?

    5) I pressed-on after dealing with #4, and I have my XO measurements taken from my one good tweeter and cabinet assembly. Prototype XO attempt #1 has been established, and should be easy to assemble tomorrow or Tuesday once some parts arrive.

    Click image for larger version

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  • Kevin K.
    replied
    Nice looking finish! Looking forward to the next round of pics, finished cabinets I presume. Good luck!

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  • KEtheredge87
    replied
    Originally posted by chocolate_soymilk View Post
    Really enjoying your updates, and thanks for posting your process on youtube as well! I love the look of the cabinet and what you've chosen to do with the facets.I’m going to rip off I’ve been inspired by the look and plan to implement a similar style on my next build.
    Thanks! Feel free to use any ideas you like. That's half the fun of posting to this forum in my opinion. Either you're sharing a new process that worked... or steering others clear of something that did NOT work! We all learn by sharing and discussing. I got my start on these forums just the same as many others. Gotta keep the community thriving!

    Leave a comment:


  • chocolate_soymilk
    replied
    Really enjoying your updates, and thanks for posting your process on youtube as well! I love the look of the cabinet and what you've chosen to do with the facets.I’ve been inspired by the look and plan to implement a similar style (i.e. rip it off) on my next build.
    Last edited by chocolate_soymilk; 04-03-2019, 05:58 PM. Reason: Removed text that was intended to be struck through, apparently that doesn't work.

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