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Measuring Mark Audio Alpair-10 gen-2

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  • Measuring Mark Audio Alpair-10 gen-2

    Building a pair of MLTLs for a customer.
    Asked for the permission to measure drivers and throw data in the public domain.
    Madisound link.
    http://www.madisoundspeakerstore.com...l-range-gen-2/
    So here it goes.
    2 drivers.

    Driver 1
    Completed: Fri Mar 09 16:00:00 2012
    Drive level 100.000 % [ 3.576 mA]
    Sine,LoZP(LV/LA)->Vas,18 pts
    ;------------------------------------------------------------------
    Re = 7.3741 ohms
    Fs = 39.4239 Hz
    Zmax = 60.9430 ohms
    Qes = 0.4893
    Qms = 3.5545
    Qts = 0.4301
    Le = 0.4012 mH (at 1 kHz)
    Diam = 98.0000 mm ( 3.8583 in )
    Sd = 7542.9636 mm^2( 11.6916 in^2)
    Vas = 15.7365 L ( 0.5557 ft^3)
    BL = 5.5901 N/A
    Mms = 8.3707 g
    Cms = 1946.9703 uM/N
    Kms = 513.6185 N/M
    Rms = 0.5833 R mechanical
    Efficiency = 0.1852 %
    Sensitivity= 84.6937 dB @1W/1m
    Sensitivity= 85.0475 dB @2.83Vrms/1m
    Krm = 10.514E-03 ohms Freq dependent resistance
    Erm = 566.234E-03 Rem=Krm*(2*pi*f)^Erm
    Kxm = 41.167E-03 Henries Freq dependent reactance
    Exm = 488.083E-03 Xem=Kxm*(2*pi*f)^Exm
    ;------------------------------------------------------------------
    Ftest = 21.414 Hz
    Ftest/Fms = 0.5432
    Test Mass used = 20.0000 g (Equal to 4.0 nickels)
    Test Mass (Ft=Fms*0.90) = 1.963 g (Add -18.037g for Ft=35.482)
    Test Mass (Ft=Fms*0.75) = 6.511 g (Add -13.489g for Ft=29.568)

    Driver2
    Completed: Fri Mar 09 16:22:06 2012
    Drive level 100.000 % [ 3.576 mA]
    Sine,LoZP(LV/LA)->Vas,18 pts
    ;------------------------------------------------------------------
    Re = 7.9401 ohms
    Fs = 40.0990 Hz
    Zmax = 58.7799 ohms
    Qes = 0.5684
    Qms = 3.6394
    Qts = 0.4916
    Le = 0.4033 mH (at 1 kHz)
    Diam = 98.0000 mm ( 3.8583 in )
    Sd = 7542.9636 mm^2( 11.6916 in^2)
    Vas = 15.9564 L ( 0.5635 ft^3)
    BL = 5.2996 N/A
    Mms = 7.9797 g
    Cms = 1974.1788 uM/N
    Kms = 506.5397 N/M
    Rms = 0.5524 R mechanical
    Efficiency = 0.1701 %
    Sensitivity= 84.3244 dB @1W/1m
    Sensitivity= 84.3571 dB @2.83Vrms/1m
    Krm = 8.610E-03 ohms Freq dependent resistance
    Erm = 581.825E-03 Rem=Krm*(2*pi*f)^Erm
    Kxm = 33.450E-03 Henries Freq dependent reactance
    Exm = 503.476E-03 Xem=Kxm*(2*pi*f)^Exm
    ;------------------------------------------------------------------
    Ftest = 21.414 Hz
    Ftest/Fms = 0.5340
    Test Mass used = 20.0000 g (Equal to 4.0 nickels)
    Test Mass (Ft=Fms*0.90) = 1.872 g (Add -18.128g for Ft=36.089)
    Test Mass (Ft=Fms*0.75) = 6.206 g (Add -13.794g for Ft=30.074)

    Both drivers were played for an hour or so then let seat and cool off.
    S&L woofer tester was calibrated prior to TS measurements.
    DC resistance was checked with DMM and matched S&L DCR.

    FR and other acoustic info will be posted in a day or two.
    Attached Files
    http://www.diy-ny.com/

  • #2
    Re: Measuring Mark Audio Alpair-10 gen-2

    I am downloading and saving these files, thanks. I have been eyeing some 10.2's for a while. Your numbers differ quite a bit from theirs, especially the sensitivity. What are you listen impressions of them?

    Comment


    • #3
      Re: Measuring Mark Audio Alpair-10 gen-2

      MA published specs here a while ago
      http://www.diyaudio.com/forums/marka...ml#post2666992
      and these are much closer to what I got.
      My concern also is the deviation in DCR (which was rechecked with DMM) between two drivers.
      The next stage will be measuring the frequency response, distortions and looking at waterfalls. I have not listened to the drivers in the system yet.

      Also, I'll give the 40hz to x-max for a few hours and remeasure. May be for this babies, an hour is not enough.
      http://www.diy-ny.com/

      Comment


      • #4
        Re: Measuring Mark Audio Alpair-10 gen-2

        Originally posted by r-carpenter View Post

        Also, I'll give the 40hz to x-max for a few hours and remeasure. May be for this babies, an hour is not enough.
        There has been discussion over on marks forum (at diyaudio) that these drivers can't be pushed to xmax for prolonged use. The cones deform. He received some flak, from myself included, for stating an xmax that couldn't be maintained. He also has a specific break in practice and says his warranty is contingent on following his recommendations for driver use.
        https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

        Comment


        • #5
          Re: Measuring Mark Audio Alpair-10 gen-2

          Originally posted by ryanbouma View Post
          There has been discussion over on marks forum (at diyaudio) that these drivers can't be pushed to xmax for prolonged use. The cones deform. He received some flak, from myself included, for stating an xmax that couldn't be maintained. He also has a specific break in practice and says his warranty is contingent on following his recommendations for driver use.
          In other words it's a poor design?
          .

          Comment


          • #6
            Re: Measuring Mark Audio Alpair-10 gen-2

            what is the specific break in practice???
            http://www.diy-ny.com/

            Comment


            • #7
              Re: Measuring Mark Audio Alpair-10 gen-2

              Could not find specifics for the 10, buy found these on others.

              From MA:

              "Small to medium sized speakers are usually lower power designs. The power rating is given in the technical data for each audio driver. For a reliable long service life, please operate your new speakers with care. For the first 100 hours, operate them at very low volumes. After this period, gradually increase the volume to a normal listening level. If you see the cone of the speakers making large movements, immediately turn the volume down. This will protect the speaker and your human hearing from damage. Factory mechanical defects for a period of 1 year. Excessive hard use (over-driving) and other damage caused during customer use is excluded from our warranty."

              For the MA 6M:

              Running in procedure:

              This driver is designed to deliver optimum results from 300 hours to 31,000 hours of normal service life on lower power amplification.

              DONʼT USE ANY ARTIFICIALLY GENERATED SOUND!
              First 30 hours, use very low volumes. Hours 30 to 100, gradually increase volume but remain gentle. 100 to 300 hours gradually into a variety of music including some bass.
              Remain gentle, sensible use of this driver will yield pleasing acoustic results.
              Peak excursion

              The Alpair 6P has a mechanical X Max (1 way) of 5.5 mm (in flux). This feature is only designed to handle non-linear “peak-shock” loads, for example the brief roll of a drum beat. For optimum movement, loads NOT exceeding 3.00 mm is within its capability for a period not exceeding 1.5 hours. The normal driven movement should remain inside 2.6 mm. For a driver of this size, this normal load X-max is generous; Together with a well matched cabinet, a pleasing bass response can be generated

              General care

              Keep the driver away from direct sun-light as the UV will breakdown to cone structure. Very high humidity could affect the stability of the cone. Donʼt use any wet cloths or very damp materials to clean the cone. A light gentle brush with a soft duster is sufficient.
              Last edited by Steve Henry; 03-10-2012, 10:42 AM. Reason: sp
              Audiophiles listen to the equipment, not the music.

              Comment


              • #8
                Re: Measuring Mark Audio Alpair-10 gen-2

                Originally posted by mzisserson View Post
                In other words it's a poor design?
                On the contrary, it's design enables it to do what few full range drivers can do for a fraction of the price. The recommended break in procedure enables the driver to perform as designed. Jim Griffin did an ML-TL and also used it open baffle with great results.

                The Bob Brines design I heard with the smaller MA at LSAF was exceptional. I understand full range is not for everyone, but things like built in baffle step & EQ for off axis response makes it different from others.
                Audiophiles listen to the equipment, not the music.

                Comment


                • #9
                  Re: Measuring Mark Audio Alpair-10 gen-2

                  http://techtalk.parts-express.com/sh...hlight=griffin

                  http://www.diyaudio.com/forums/full-...tl-design.html

                  I will be curious to see if r-carpenter's measurements confirm Alpair's.
                  Attached Files
                  Audiophiles listen to the equipment, not the music.

                  Comment


                  • #10
                    Re: Measuring Mark Audio Alpair-10 gen-2

                    Steve, nobody is insulting Jim's or Bob's designs here.
                    I am somewhat but not awfully interested in listening to Alpair 10.2 but the name of the thread is "measuring". Mike is bringing up the point of the driver's limitation, and perhaps he's rough around about it. ;)
                    Now, from the description of break in, it sounds like I'd need to baby the 10.2 for at list a week. May be play some violin at 75db?
                    http://www.diy-ny.com/

                    Comment


                    • #11
                      Re: Measuring Mark Audio Alpair-10 gen-2

                      Originally posted by r-carpenter View Post
                      Steve, nobody is insulting Jim's or Bob's design here.
                      I am somewhat but not awfully interested in listening to Alpair 10.2 but the name of the thread is "measuring". Mike is bringing up the point of the driver's limitation, and perhaps he's rough around about it. ;)
                      Now, from the description of break in, it sounds like I'd need to baby the 10.2 for at list a week. May be play some violin at 75db?
                      Sorry - not my intention. Just wanted to make sure the break-in procedure was specified for a reason and that "poor design" was not confirmed by others. As always, YMMV.
                      Audiophiles listen to the equipment, not the music.

                      Comment


                      • #12
                        Re: Measuring Mark Audio Alpair-10 gen-2

                        The subject is NOT "oh how I like full range drivers" or "full range systems suck!". This is not about you subjective preferences or particular designs. It is NOT about benefits or disadvantages of one system over another.

                        This thread is ONLY about measuring the driver. That's all. Nothing less, nothing more.
                        This driver is like any other drivers, a tool and used properly within it's limitations, can be a benefit.;)
                        http://www.diy-ny.com/

                        Comment


                        • #13
                          Re: Measuring Mark Audio Alpair-10 gen-2

                          r-carpenter, my apologies for getting your thread off track. My intention was to make aware that the break-in procedures recommended by MA may affect independent measurements and/or designs. I eagerly await your findings and final observations.
                          Audiophiles listen to the equipment, not the music.

                          Comment


                          • #14
                            Re: Measuring Mark Audio Alpair-10 gen-2

                            Originally posted by r-carpenter View Post
                            The subject is NOT "oh how I like full range drivers" or "full range systems suck!". This is not about you subjective preferences or particular designs. It is NOT about benefits or disadvantages of one system over another.

                            This thread is ONLY about measuring the driver. That's all. Nothing less, nothing more.
                            This driver is like any other drivers, a tool and used properly within it's limitations, can be a benefit.;)
                            Sorry I guess I did get off your topic.
                            Dave

                            If you can read this, thank a teacher.
                            If you are reading it in English thank a Veteran
                            .

                            Comment


                            • #15
                              Re: Measuring Mark Audio Alpair-10 gen-2

                              Originally posted by Wushuliu
                              FYI, that link refers to the 'special edition' Alpair 10 which is not in production yet, not the 10.2 currently available.
                              Also, more measurements can be found at Bob's site.
                              yep, I see it now. Thanks.

                              Originally posted by Steve Henry View Post
                              r-carpenter, my apologies for getting your thread off track. My intention was to make aware that the break-in procedures recommended by MA may affect independent measurements and/or designs. I eagerly await your findings and final observations.
                              Thanks for pointing out how MA wants to break in the driver. I have couple of findings and will share in a minute.

                              Originally posted by dthomas View Post
                              Sorry I guess I did get off your topic.
                              no biggie. I just didn't want this to turn in to mud throwing between multiway/fullrange fans.
                              http://www.diy-ny.com/

                              Comment

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