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  • vented vs MLTL enclosure

    Hi All

    I am simulating enclosure for a pair of driver from my friend.

    I use Jeff's woofer design 5 to simulate,I got pretty satisfy graph(attachment 1.)

    But I am still curious if it is ML-TL enclosure how deep can this system go

    here is T/S parameters that I measured using DATS earlyer

    * f(s)= 54.51 Hz
    * R(e)= 7.49 Ohms
    * Z(max)= 79.91 Ohms
    * Q(ms)= 6.463
    * Q(es)= 0.668
    * Q(ts)= 0.606
    * V(as)= 22.860 liters (0.807 cubic feet)
    * L(e)= 0.87 mH
    * n(0)= 0.53 %
    * SPL= 89.33 1W/1m
    * M(ms)= 8.67 grams
    * C(ms)= 0.98 mm/N
    * BL= 5.77
    the Xmax is 6mm

    Thanks!
    Keith
    Attached Files

  • #2
    Re: vented vs MLTL enclosure

    Whats the driver and the Sd?
    John H

    Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

    Comment


    • #3
      Re: vented vs MLTL enclosure

      The driver is Aurum Cantus AC-130 Signature different from we can get in PE.I'll post the picture later.Sd =81cm^2
      Last edited by lct0221; 08-04-2013, 07:37 AM.

      Comment


      • #4
        Re: vented vs MLTL enclosure

        the calculated mms, cms, and bl don't match. looks like something is off. do you have any published parameters?

        Aurum Cantus special
        Fs 54.51 Hz
        Re 7.49 Ohm
        Qms 6.46
        Qes 0.67
        Effective Qts 0.605
        Sd 81.0 cm2
        Vas 22.0 l
        Xmax peak 6.00 mm
        Rms 0.189 kg/s
        (Le) 0.87 mH

        Mms 3.57 g
        Cms 2.387 mm/N
        Bl 3.70 Tm
        John H

        Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

        Comment


        • #5
          Re: vented vs MLTL enclosure

          John

          I do have published parameters,but the sheet look totally like a different driver

          datas from the sheet shows
          BL (Flux*Length)= 6.9886 TM
          Cms(Compliance)=1482.7120 uM/N
          Mms(Total Mass)= 8.7272 Gram

          Why are this three so important in simulating box?

          Do I need to measure again ?

          Keith

          Comment


          • #6
            Re: vented vs MLTL enclosure

            Generally we want to confirm that your driver is close to the published parameters to
            1. Confirm the driver is not defective
            2. Confirm your measurement technique is correct.

            New drivers need a bit of break in to get close to the published parameters. You can always check the second driver for confirmation.

            Best to confirm the driver specs before spending time on a simulation.
            John H

            Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

            Comment


            • #7
              Re: vented vs MLTL enclosure

              I did some exploratory modeling for an ML-TL using your T/S measurements. I did not, however, check the apparent validity of Bl and Vas, and I also estimated an Sd of 95 cm2 based on other AC drivers of the same size. It also wasn't clear to me if there would be one or two of these drivers in the same box, but as it turned out, neither version could possibly survive an input of 150 watts as in your posted graph; Xmax would be exceeded at all frequencies below about 120 Hz. I didn't want to post something that was disappointing, especially if I possibly made a mistake, but now that John Hollander has chimed in, maybe my info will be useful.
              Paul

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              • #8
                Re: vented vs MLTL enclosure

                Be advised that Aurum Cantus woofers are notorious for not corresponding to manufacturers specs. That said, your driver's AC130 siblings make some very nice music - just not in the same way as would be expected from the specs.

                Tell us where we can find a sheet or the driver. Sounds like an interesting one.

                Comment


                • #9
                  Re: vented vs MLTL enclosure

                  Originally posted by jhollander View Post
                  Generally we want to confirm that your driver is close to the published parameters to
                  1. Confirm the driver is not defective
                  2. Confirm your measurement technique is correct.

                  New drivers need a bit of break in to get close to the published parameters. You can always check the second driver for confirmation.

                  Best to confirm the driver specs before spending time on a simulation.
                  That would be bad advice in this case, as the AC130 will never measure close to the advertised specs. However, they do measure very consistenly and most of his numbers are very close to those of the AC130f-1, close enough that I would tend to trust them (the Fs, Qes, Qms, Vas values anyway).

                  Jeff
                  Click here for Jeff Bagby's Loudspeaker Design Software

                  Comment


                  • #10
                    Re: vented vs MLTL enclosure

                    Originally posted by Jeff B. View Post
                    That would be bad advice in this case, as the AC130 will never measure close to the advertised specs. However, they do measure very consistenly and most of his numbers are very close to those of the AC130f-1, close enough that I would tend to trust them (the Fs, Qes, Qms, Vas values anyway).

                    Jeff
                    Good to know, we'll through out the other measurments and go with the Fs, Qes, Qms, Vas for some quicky sims.

                    Thanks

                    Paul, I'll do a quick MLTL with horn respose to see how it compares to your math cad model.
                    John H

                    Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                    Comment


                    • #11
                      Re: vented vs MLTL enclosure

                      I actually never came up with an ML-TL model of any line length that I would want to listen to; therefore, not one I would recommend for someone else. I did not try an ML-TQWT, which may work better, and I don't know how much any "errors" in the posted T/S values contributed to my unsatisfactory modeling results. I am confident, however, that it's simply not possible to subject two, much less one of these AC130S drivers to an input of 150 watts, unless one likes to hear bad-sounding noises and/or watch smoke being emitted by their speakers.
                      Paul

                      Originally posted by jhollander View Post
                      Good to know, we'll through out the other measurments and go with the Fs, Qes, Qms, Vas for some quicky sims.

                      Thanks

                      Paul, I'll do a quick MLTL with horn respose to see how it compares to your math cad model.

                      Comment


                      • #12
                        Re: vented vs MLTL enclosure

                        Well, 36 liters seems just too big. Playing with unibox maybe fb of 40, f3 of 38 in 36 liters. You would still need a hi pass at 35 to 40 Hz. 8 or 9 watts max, just under 100 Db.
                        Tried a mltl in horn response and it just doesn’t work well.

                        Looks like it would make an outstanding mid…excellent dipole mid.
                        John H

                        Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                        Comment


                        • #13
                          Re: vented vs MLTL enclosure

                          Originally posted by Paul K. View Post
                          I actually never came up with an ML-TL model of any line length that I would want to listen to; therefore, not one I would recommend for someone else. I did not try an ML-TQWT, which may work better, and I don't know how much any "errors" in the posted T/S values contributed to my unsatisfactory modeling results. I am confident, however, that it's simply not possible to subject two, much less one of these AC130S drivers to an input of 150 watts, unless one likes to hear bad-sounding noises and/or watch smoke being emitted by their speakers.
                          Paul
                          You lost me here. Do you mean with this woofer? Because you have done a lot of MLTL designs.
                          Click here for Jeff Bagby's Loudspeaker Design Software

                          Comment


                          • #14
                            Re: vented vs MLTL enclosure

                            That's exactly what I meant, Jeff. Not all drivers work well in anything but a simple vented box and hiccups start to develop with drivers having a low or high Qts. John Hollander appears to agree with my assessment for this driver. The primary deficiency I found was a broad dip in the response over an octave wide in the 100-200 Hz range, with some "ugly" dips and peaks elsewhere. That broad dip is the so-called "ML-TL dip" that frequently appears in ML-TL designs to some extent or another, but it's really severe with some drivers, like this one (based on the OP's T/S values, at least). I don't know about John, but I'm really picky when it comes to the response shape. I've attached what I consider to be a more or less ideal response shape for an ML-TL (for an SB17, BTW). While this is not always achievable, it's what I shoot for because my gut feeling says it will sound best in a variety of acoustical environments. Others may disagree and that's okay.
                            Paul
                            Click image for larger version

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                            Originally posted by Jeff B. View Post
                            You lost me here. Do you mean with this woofer? Because you have done a lot of MLTL designs.

                            Comment


                            • #15
                              Re: vented vs MLTL enclosure

                              Originally posted by Paul K. View Post
                              That's exactly what I meant, Jeff. Not all drivers work well in anything but a simple vented box and hiccups start to develop with drivers having a low or high Qts. John Hollander appears to agree with my assessment for this driver. The primary deficiency I found was a broad dip in the response over an octave wide in the 100-200 Hz range, with some "ugly" dips and peaks elsewhere. That broad dip is the so-called "ML-TL dip" that frequently appears in ML-TL designs to some extent or another, but it's really severe with some drivers, like this one (based on the OP's T/S values, at least). I don't know about John, but I'm really picky when it comes to the response shape. I've attached what I consider to be a more or less ideal response shape for an ML-TL (for an SB17, BTW). While this is not always achievable, it's what I shoot for because my gut feeling says it will sound best in a variety of acoustical environments. Others may disagree and that's okay.
                              Paul
                              [ATTACH=CONFIG]38601[/ATTACH]
                              I think Floyd Toole may disagree with you, or at least say you are being too stringent. In most of our listening rooms the Schroeder Frequency is in the 200-240Hz range so it is unlikely that we will be able to perceive small amounts of response ripple much below this frequency.

                              But you answered my question, you meant just with this woofer.
                              Click here for Jeff Bagby's Loudspeaker Design Software

                              Comment

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