Announcement

Collapse
No announcement yet.

Easy ZMA and T/S Parameters Using The LIMP Module in ARTA - An Illustrated Guide

Collapse
This is a sticky topic.
X
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    Setup>Measurement>Averaging>Linear>Max Averages 1 will do a single burst. At work so cannot confirm 100% this is correct, will double-check when I get home.

    Great thread, by the way - home made jigs and free software are definitely in the spirit of DIY.
    Don't listen to me - I have not sold any $150,000 speakers.

    Comment


    • #32
      Originally posted by johnnyrichards View Post
      Setup>Measurement>Averaging>Linear>Max Averages 1 will do a single burst. At work so cannot confirm 100% this is correct, will double-check when I get home.

      Great thread, by the way - home made jigs and free software are definitely in the spirit of DIY.
      Good memory for an old man! Yep, that's the setting! Thanks Johnny.
      Some people are addicted to Vicodin. I'm addicted to speaker building.

      The Chorales - Usher 8945A/Vifa XT25TG Build
      ESP Project 101 Lateral MOSFET Amplifier
      LM4780 Parallel Chipamp
      Sonata Soundbar Project
      The Renditions - Active/Passive Towers

      Comment


      • #33
        Thanks Hong
        I've got to explore the pink noise option.

        I think I hear a difference - wow, it's amazing!" Ethan Winer: audio myths
        "As God is my witness I'll never be without a good pair of speakers!" Scarlett O'Hara

        High value, high quality RS150/TB28-537SH bookshelf - TARGAS NLA!
        SB13/Vifa BC25SC06 MTM DCR Galeons-SB13-MTM
        My Voxel min sub Yet-another-Voxel-build

        Tangband W6-sub

        Comment


        • #34
          Great write up Hong! How important is it to have an Intel chip? I run an AMD in my computer but the wife's laptop is an I3.
          See my projects on Instagram and Facebook

          Comment


          • #35
            Originally posted by Derekj View Post
            Great write up Hong! How important is it to have an Intel chip? I run an AMD in my computer but the wife's laptop is an I3.
            ARTA is pretty much cpu independent so no worries.
            Don't listen to me - I have not sold any $150,000 speakers.

            Comment


            • #36
              Originally posted by johnnyrichards
              ARTA is pretty much cpu independent so no worries.
              Thanks JR!
              See my projects on Instagram and Facebook

              Comment


              • #37
                So I built my jig and installed the software. Following the instructions I hooked a driver up to my jig and tried an impedance measurement. This is what I got, any ideas? I have a Creative x-fi titanium card. I tried to google the volume settings in windows for Limp but couldn't find anything.

                See my projects on Instagram and Facebook

                Comment


                • #38
                  Great guide! Thank you!

                  The following are all minor comments from my preferences.

                  Resistors are typically cheap and if you are already placing an order with one of the "other" electronics suppliers, you might want to specifically get a higher tolerance and specifically non-inductive resistor. For example, VIshay CPF3100R00BEE36 is about a dollar and is 0.1% 3W metal film (non-inductive), silicone coated and has a low temperature coefficient. So it should be darn near 100 Ohms darn near all the time. On the other hand you could get a 100 Ohm wirewound that has some impedance that impacts the measurement (but I haven't run a tolerance study --- an RS180-4 is about 0.45mH though). Some wirewounds have a special winding to make them non-inductive, but metal film resistors are typically the lowest inductance resistor flavor, and some piece of mind is never a bad thing.

                  If portability is key, one might consider flying cables to 3.5mm/RCA plugs and/or Pomona Mini-Grabber's (alas $$$) on the speaker side --- you can beat the size of the DATS-V2 this way and you can typically avoid the alligators inevitably snapping off the terminals if the grabbers can hook thru/onto the speaker's terminals. And you don't have to have a project box, just some creative soldering and heatshrinking should do it.

                  I was under the impression that the "reference" orientation for impedance testing was with the axis of the driver parallel to the ground, e.g. driver vertical, such that gravity was not acting in-line with the coil. It may not make much of a difference for most drivers (?), and the stated orientation in the tutorial is far easier for the added mass method and most importantly it's generally much harder to keep the driver stable when vertical and without a fixture.

                  This should be obvious, but in case it isn't to some newbies, but the testing should be done in a quiet location. Speakers are microphones after all.

                  Finally (and also obvious as above) it is often a good idea to repeat the same measurement (same serial number and test process) and understand the observed vs. expected variation.
                  --Derek

                  Comment


                  • #39
                    Originally posted by Derekj View Post
                    So I built my jig and installed the software. Following the instructions I hooked a driver up to my jig and tried an impedance measurement. This is what I got, any ideas? I have a Creative x-fi titanium card. I tried to google the volume settings in windows for Limp but couldn't find anything.
                    @Derekj,

                    Assuming that it is a full duplex card, I would check to make sure that the drivers are loaded correctly, and that they show up when you select "Audio Devices" under the "Setup" menu. Also, was the calibration successful? Check out section 4.2 of the LIMP manual, "Soundcard" Setup for more details. Good luck and let us know if you're able to resolve this issue.

                    http://artalabs.hr/download/LIMP-user-manual.pdf
                    Some people are addicted to Vicodin. I'm addicted to speaker building.

                    The Chorales - Usher 8945A/Vifa XT25TG Build
                    ESP Project 101 Lateral MOSFET Amplifier
                    LM4780 Parallel Chipamp
                    Sonata Soundbar Project
                    The Renditions - Active/Passive Towers

                    Comment


                    • #40
                      Originally posted by deschu View Post
                      Great guide! Thank you!

                      The following are all minor comments from my preferences.

                      Resistors are typically cheap and if you are already placing an order with one of the "other" electronics suppliers, you might want to specifically get a higher tolerance and specifically non-inductive resistor. For example, VIshay CPF3100R00BEE36 is about a dollar and is 0.1% 3W metal film (non-inductive), silicone coated and has a low temperature coefficient. So it should be darn near 100 Ohms darn near all the time. On the other hand you could get a 100 Ohm wirewound that has some impedance that impacts the measurement (but I haven't run a tolerance study --- an RS180-4 is about 0.45mH though). Some wirewounds have a special winding to make them non-inductive, but metal film resistors are typically the lowest inductance resistor flavor, and some piece of mind is never a bad thing.

                      If portability is key, one might consider flying cables to 3.5mm/RCA plugs and/or Pomona Mini-Grabber's (alas $$$) on the speaker side --- you can beat the size of the DATS-V2 this way and you can typically avoid the alligators inevitably snapping off the terminals if the grabbers can hook thru/onto the speaker's terminals. And you don't have to have a project box, just some creative soldering and heatshrinking should do it.

                      I was under the impression that the "reference" orientation for impedance testing was with the axis of the driver parallel to the ground, e.g. driver vertical, such that gravity was not acting in-line with the coil. It may not make much of a difference for most drivers (?), and the stated orientation in the tutorial is far easier for the added mass method and most importantly it's generally much harder to keep the driver stable when vertical and without a fixture.

                      This should be obvious, but in case it isn't to some newbies, but the testing should be done in a quiet location. Speakers are microphones after all.

                      Finally (and also obvious as above) it is often a good idea to repeat the same measurement (same serial number and test process) and understand the observed vs. expected variation.
                      Derek, very valid points about the quality of the resistor. Thanks for your feedback.

                      Hong
                      Some people are addicted to Vicodin. I'm addicted to speaker building.

                      The Chorales - Usher 8945A/Vifa XT25TG Build
                      ESP Project 101 Lateral MOSFET Amplifier
                      LM4780 Parallel Chipamp
                      Sonata Soundbar Project
                      The Renditions - Active/Passive Towers

                      Comment


                      • #41
                        One common error in LIMP jigs is not properly wiring said jig, Derekj

                        Take a few minutes and go through it again. After a few head scratching moments, I ended up re-drawing the schematic in a way that made it easier for me to understand:

                        Click image for larger version

Name:	image_49087.png
Views:	2
Size:	8.7 KB
ID:	1314915

                        Then, follow Hong's excellent advice. If you have more than one soundcard installed on the system LIMP will sometimes default to the wrong input/output. Also check to make sure LIMP did not select a mic input instead of a line input.
                        Don't listen to me - I have not sold any $150,000 speakers.

                        Comment


                        • #42
                          I also recently made a simple tool for impedance/TS parameter measurement with REW. 3D printed case with 100ohm resistor and switch for calibration. Connection with sound card is with 2 aux cables and the output has 2 alligator clips.

                          http://imgur.com/a/sgR06

                          Comment


                          • #43
                            Wow, hongrn , well done! This should definitely be a sticky.
                            "The ability of any system to produce exceptional sound will be limited mainly by the capability of the speakers" Jim Salk
                            "Audio is surely a journey full of revelations as you go" JasonP

                            Comment


                            • #44
                              Originally posted by hongrn View Post

                              @Derekj,

                              Assuming that it is a full duplex card, I would check to make sure that the drivers are loaded correctly, and that they show up when you select "Audio Devices" under the "Setup" menu. Also, was the calibration successful? Check out section 4.2 of the LIMP manual, "Soundcard" Setup for more details. Good luck and let us know if you're able to resolve this issue.

                              http://artalabs.hr/download/LIMP-user-manual.pdf
                              When I run the Setup for audio devices it shows my Creative Sound card. The calibration runs successfully too. I followed the setup up procedure in the manual for setting up the card. Here are a few screenshots of the settings I used for speakers and recording. At first I was using the rca inputs on my sound card, then I tried the microphone input on the back of the sound card which is what the screenshot shows.

                              I checked the wiring for the jig as per JR's diagram and it seems ok. I checked all my connections with my meter when I put it together.

                              johnnyrichards where do you tell Limp which input you are using? Is it just in setup/audio devices?
                              See my projects on Instagram and Facebook

                              Comment


                              • #45
                                Originally posted by Derekj View Post

                                When I run the Setup for audio devices it shows my Creative Sound card. The calibration runs successfully too. I followed the setup up procedure in the manual for setting up the card. Here are a few screenshots of the settings I used for speakers and recording. At first I was using the rca inputs on my sound card, then I tried the microphone input on the back of the sound card which is what the screenshot shows.

                                I checked the wiring for the jig as per JR's diagram and it seems ok. I checked all my connections with my meter when I put it together.

                                johnnyrichards where do you tell Limp which input you are using? Is it just in setup/audio devices?


                                Yessir
                                Don't listen to me - I have not sold any $150,000 speakers.

                                Comment

                                Working...
                                X