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T-B W3-2141 measuring way off spec - anyone else used this driver?

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  • T-B W3-2141 measuring way off spec - anyone else used this driver?

    Has anyone else worked with the T-B W3-2141?

    Collaborating on a project and pulling some early data, and they seem to measure drastically different from published.
    This is taped to the baffle not flush-mounted, so I'd expect a little diffraction but not the 10dB peak at ~2900Hz and the dip at 4k. Impedance changes shape like spec, but at ~3200 vs ~1600

    Update: T/S parameters for the two drivers I've been measuring.

    Loudspeaker parameters:

    Fs = 124.79 Hz
    Re = 7.10 ohm[dc]
    Le = 55.99 uH
    L2 = 340.99 uH
    R2 = 4.47 ohm
    Qt = 0.47
    Qes = 0.65
    Qms = 1.75
    Mms = 1.82 grams
    Rms = 0.814988 kg/s
    Cms = 0.895738 mm/N
    Vas = 1.15 liters
    Sd= 30.19 cm^2
    Bl = 3.956203 Tm
    ETA = 0.33 %
    Lp(2.83V/1m) = 87.83 dB

    Added Mass - Constant Bl Method:
    Driver unbaffled
    Added mass = 3.20 grams
    Membrane Diameter= 6.20 cm

    Loudspeaker parameters:

    Fs = 126.60 Hz
    Re = 7.10 ohm[dc]
    Le = 55.29 uH
    L2 = 317.53 uH
    R2 = 4.68 ohm
    Qt = 0.43
    Qes = 0.60
    Qms = 1.52
    Mms = 2.31 grams
    Rms = 1.213469 kg/s
    Cms = 0.683138 mm/N
    Vas = 0.87 liters
    Sd= 30.19 cm^2
    Bl = 4.662416 Tm
    ETA = 0.28 %
    Lp(2.83V/1m) = 87.15 dB

    Added Mass - Constant Bl Method:
    Driver unbaffled
    Added mass = 3.20 grams
    Membrane Diameter= 6.20 cm

    Really disappointing results.

    C
    Last edited by cjd; 02-21-2021, 06:43 PM.
    diVine Audio

  • #2
    I suppose you've already let them run in a little?

    Did you already try it flush mounted?

    You could always just measure the drivers out of the box purely to see if there is a difference?

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    • #3
      Manufactures specs are advertising.

      Comment


      • #4
        Originally posted by DeZZar View Post
        I suppose you've already let them run in a little?

        Did you already try it flush mounted?

        You could always just measure the drivers out of the box purely to see if there is a difference?
        This is my usual process, and I've never had anything measure this far off spec. Fs is usually higher and other little stuff. I even went back to re-measure stuff I've already done just to validate nothing went weird with my measurement rig.

        I always do a few cycles just to see how things change for a driver. These have a little burn-in time on them, but they're now getting more. Also getting around to setting up a proper test baffle again where I'll flush-mount anything by making a new insert. Maybe this is something to do with the treated surround and it'll change more with break-in than I've seen before.

        Waiting to do final cabinet work till I've settled on a driver for sure, as I have a few options still right now... that kinda goes away once I recess for flush-mounting.

        Originally posted by tvrgeek View Post
        Manufactures specs are advertising.
        Yeah, and T-B is typically a little optimistic. I've used drivers from them before. But this seems wildly optimistic, or an indication of a problem in manufacturing which they haven't caught. Not sure yet, but that's why I stopped in to ask.
        diVine Audio

        Comment


        • #5
          I know you're (primarily) looking at FR, but did you T/S parm your drivers (just curious)?

          cjr

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          • #6
            Originally posted by Chris Roemer View Post
            I know you're (primarily) looking at FR, but did you T/S parm your drivers (just curious)?

            cjr
            Nope. I have to reread the manual, don't remember a thing about doing that other than I hated it. Re sure looks to be higher than spec though...
            diVine Audio

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            • #7
              Do yourself a favor and get a DATS / WooferTester for TS parameters.

              Comment


              • #8
                I'm guessing from the responses no one else really has experience with this driver.

                Originally posted by tvrgeek View Post
                Do yourself a favor and get a DATS / WooferTester for TS parameters.
                I hate having to fiddle with adding mass or sorting box volume accurately... Not sure I vhave a way to do mass at the moment, either misplace or tossed when we moved a few years ago. Though I can still get free air data which would be useful in this instance. What's the latest DATS do which I don't already have tools to do?

                Edit: actually should probably use taped weight here anyway to avoid staining. Hopefully that doesn't damage the cone...
                diVine Audio

                Comment


                • #9
                  Chris, you've been away too long that people don't know you. 😀

                  ​​​​​​I once upon a time had a Woofer Tester (version 2 I think). I lent/gave it to someone, becuase I wasnt really ever going to use it. I don't remember who I gave it to. You'd be the most likely candidate. Maybe it was JonW?? You might dig through your boxes and see if it is in one. Don't know how useful it'd be to you, becuase I thought it took impedance real easy but still did the added mass method to get the full t/s. I don't really remember.
                  - Ryan

                  CJD Ochocinco ND140/BC25SC06 MTM & TM
                  CJD Khanspires - A Dayton RS28/RS150/RS225 WMTMW
                  CJD Khancenter - A Dayton RS28/RS150/RS180 WTMW Center
                  CJD In-Khan-Neatos - A Dayton RS180/RS150/RS28 In/On Wall MTW

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                  • #10
                    Hi Chris, good to see you posting again. I haven't used that TB W3, but I have used several other of their drivers. None of them have measured very closely to the manufacturer's spec. Some have sounded fantastic though. Some just meh. Based on your measurements I'd move on and pick a different driver.

                    PS. are you still road racing/auto-crossing that little coupe?
                    Craig

                    The lowest possible F3 box alignment is not always the best alignment.

                    Designing and building speaker projects are like playing with adult Lego Blocks for me.

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                    • #11
                      You don't know me, but we spoke at an Iowa DIY years ago. I'm building 3 of your RS150 MTMs, after picking up enough RS150S-8s. I hope they sound as good as your 3 way design at the DIY event. Build thread later this year when it warms up.

                      Comment


                      • #12
                        Originally posted by ---k--- View Post
                        Chris, you've been away too long that people don't know you. 😀

                        ​​​​​​I once upon a time had a Woofer Tester (version 2 I think). I lent/gave it to someone, becuase I wasnt really ever going to use it. I don't remember who I gave it to. You'd be the most likely candidate. Maybe it was JonW?? You might dig through your boxes and see if it is in one. Don't know how useful it'd be to you, becuase I thought it took impedance real easy but still did the added mass method to get the full t/s. I don't really remember.
                        Unfortunately I don't have your woofer tester! That would have been helpful just to triple check some of the data. Oh well. I'll get around to added mass - doesn't take much for these little drivers.
                        As for being away too long, maybe. I've also been away and forgotten some details, so don't object to the reminders.

                        Originally posted by PWR RYD View Post
                        Hi Chris, good to see you posting again. I haven't used that TB W3, but I have used several other of their drivers. None of them have measured very closely to the manufacturer's spec. Some have sounded fantastic though. Some just meh. Based on your measurements I'd move on and pick a different driver.

                        PS. are you still road racing/auto-crossing that little coupe?
                        Yeah, not entirely my choice in driver though. We'll see how this goes. I think they'd do fine as reasonably wideband mids even. Might be able to beat them into usable shape full-range, we'll see. Sometimes that's half the fun?
                        Also yeah, still racing a BRZ, though I'm on my second one. Codriver crashed the first one! Also not so much 2020, probably not 2021; I need to hide away till we're all vaccinated and stuff, so a lot more sim racing this year.

                        Originally posted by djg View Post
                        You don't know me, but we spoke at an Iowa DIY years ago. I'm building 3 of your RS150 MTMs, after picking up enough RS150S-8s. I hope they sound as good as your 3 way design at the DIY event. Build thread later this year when it warms up.
                        Did I do a version with the S-8? Ha. I don't recall that. I still have mine, and they still sound good. Different from the Nebbiolo in a lot of ways. I've actually tucked mine away lately. I should get them out! Anyhow, have fun with the build and I hope you enjoy.
                        diVine Audio

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                        • #13
                          Good to see you pop in, Chris!
                          Wolf
                          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                          "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
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                          "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                          *InDIYana event website*

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                          • #14
                            This is a gated measurement of a W3 2141 in a ~2.5l enclosure. I purchased the driver about 18months ago from PE.
                            Attached Files

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                            • #15
                              ...And the baffle dimensions are about 13.5 x 16cm.

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