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  • TS parameters from DATS insufficient for WinISD database.

    OK. I started using DATS to get the TS parameters for an unknown driver. I get most of the TS values except figures like Xmax, BL, Pe and Sd. I can get a rough value for Sd but how do I get the value for the others for insertion into WinISD database? Do I need all these figures to do a quick check on the type of box I would need for the driver being tested? Thanks in advance.

  • #2
    Re: TS parameters from DATS insufficient for WinISD database.

    WinISD will calculate BL. Sd you can get close enough by comparison to another driver of the same nominal size. Pe and Xmax you can't get without literally destroying the driver. You can design without those, but won't know how loud it can go without finding out the hard way.
    www.billfitzmaurice.com
    www.billfitzmaurice.info/forum

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    • #3
      Re: TS parameters from DATS insufficient for WinISD database.

      I enter these values into WinISD (Pro) in this order:
      DATS: Qes
      DATS: Qms
      (WinISD then calcs Qts - do NOT enter its data from DATS)
      DATS: Fs
      DATS: Vas
      DATS: Re
      (for Dd you measure the dia. of the cone + 1/2 the surround, WinISD then calcs Sd)
      DATS: Le - make sure you're measuring at 1kHz (10kHz is for tweeters only)

      You'll have to look up specs for Xmax and Pe. DATS has no way of estimating those values as it can't "measure" them.

      WinISD will calculate all other pertinent parameters, like: Mms, Cms, Rms, BL, Vd, and TWO sensitivity levels (I BELIEVE that one is dB/1w and the other is dB/2.83v - which so almost be the same for 8Ω drivers only).

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      • #4
        Re: TS parameters from DATS insufficient for WinISD database.

        OK thanks. I got the beta version of WinISD so that may not have a calculate BL function.

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        • #5
          Re: TS parameters from DATS insufficient for WinISD database.

          Originally posted by Chris Roemer View Post
          I enter these values into WinISD (Pro) in this order:
          DATS: Qes
          DATS: Qms
          (WinISD then calcs Qts - do NOT enter its data from DATS)
          DATS: Fs
          DATS: Vas
          DATS: Re
          (for Dd you measure the dia. of the cone + 1/2 the surround, WinISD then calcs Sd)
          DATS: Le - make sure you're measuring at 1kHz (10kHz is for tweeters only)

          You'll have to look up specs for Xmax and Pe. DATS has no way of estimating those values as it can't "measure" them.

          WinISD will calculate all other pertinent parameters, like: Mms, Cms, Rms, BL, Vd, and TWO sensitivity levels (I BELIEVE that one is dB/1w and the other is dB/2.83v - which so almost be the same for 8Ω drivers only).
          Ditto. Thanks for the tips. Will try this method. I need to get the PRO version looks like.

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          • #6
            Re: TS parameters from DATS insufficient for WinISD database.

            The Pro ("alpha") version double checks all the entered parms., and if it rejects any, you're out of luck.

            The beta vers. doesn't actuall use any of the parms like BL anyhow. For what it does, you only need to enter Vas, Fs, and Qts, but it doesn't show you plots of maximum power, impedance, and such.

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            • #7
              Re: TS parameters from DATS insufficient for WinISD database.

              http://gonecatfishin.net/Winisd.htm
              Don't listen to me - I have not sold any $150,000 speakers.

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              • #8
                Re: TS parameters from DATS insufficient for WinISD database.

                I downloaded the pro version and played around with it a bit. I was actually playing around to see what sort of enclosure I would get for a Celestion 5 mark 2 mid woofer. This driver came with a ported enclosure with a 1" port. But seems like WinISD recommend this driver to be used in a sealed enclosure. I checked with an online speakerbox calculator and that suggested the same thing, sealed enclosure.

                As an exercise what value of QTC should I be using to design the enclosure volume? I used 0.9 and it suggested a 2.3ft3 sealed enclosure. When I put a 1 to it and the enclosure doubled in size.

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                • #9
                  Re: TS parameters from DATS insufficient for WinISD database.

                  Originally posted by johnnyrichards View Post
                  Thanks for the link Johnny. Will run through the tutorial and hopefully I can pick up more on this topic.

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                  • #10
                    Re: TS parameters from DATS insufficient for WinISD database.

                    . . . probably not. Smaller boxes create higher Qtc values, not the other way around.

                    If you gave someone your T/S parms, they could try to replicate what you're saying, otherwise, no way.

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                    • #11
                      Re: TS parameters from DATS insufficient for WinISD database.

                      what would be a good rule of thumb for Xmax and Pe if dealing with a unknown driver and no available specs?
                      THOMAS BROWN aka "STINKY"

                      I've got an idea - an idea so smart that my head would explode if I even began to know what I'm talking about. - Peter Griffin

                      I DON'T CARE WHAT KIND OF MUSIC YOU LISTEN TO, OR LIKE.
                      SHUT UP, PUT DOWN THE WALLS OF PRETENSION FOR 1 SECOND AND JUST LISTEN TO THE SONGS
                      - SCOTT IAN

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                      • #12
                        Re: TS parameters from DATS insufficient for WinISD database.

                        Tom, that's a toughie. The 8 and 10" Peerless India buyouts only had 4mm of Xmax and a Pe of 40 watts. Many of MCM 5-5.25"-6.5" drivers on have a 2-2.5 mm Xmax and Pe's from 20-80 watts, then some 6.5"er's have Xmax's of 7mm and Pe of 140 watts and anything in between. I've never found a good method to estimate Xmax and Pe from other parameters. A heavy magnet can mean a robust motor, and IF you can find the voice coil winding height in mm, somewhere between 1/4 and 1/3 of it may be a decent "guesstiment" of Xmax. A multiple layer voice coil winding might be an indication of the power handling compared to "similar drivers", whatever that means. There's a later version of WinISP called WinPRO (not the Alpha version) that's a bit more powerful. Google it, and download it and try it.

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                        • #13
                          Re: TS parameters from DATS insufficient for WinISD database.

                          Take a guess.

                          If you know the v.c. diameter, compare to others of the same size and average those for Pe.
                          Xmax? I know 4" drivers that can push 6-8mm OK, others, 1.5mm or less.
                          I know 10" drivers than are 3mm, some are 19mm.

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                          • #14
                            Re: TS parameters from DATS insufficient for WinISD database.

                            Don't worry about Xmax, only a handful of drivers out of the thousands made are linear to their advertised excursion.
                            Don't listen to me - I have not sold any $150,000 speakers.

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                            • #15
                              Re: TS parameters from DATS insufficient for WinISD database.

                              Chris and Johnny, OK, you win. And you're both right too. Guess, flip a coin, pin numbers on a wall and throw an old-fashioned dart at them. Try a half dozen numbers in the driver parameters chart in Alpha or PRO. Some won't graph. I guessed with-in .5mm of "spec" on the Iwai Indian made drivers this way before I got the "skinny" on them.

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