Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Measurement Ideas and Input

  1. #1
    Tester Extraordinaire ErinH's Avatar
    Join Date
    Aug 2010
    Posts
    1,247

    Measurement Ideas and Input

    I've got a few ideas of things I have been wanting to test and will list them below. I am looking for input from the community on things you'd like to see done and if I have the means then I'll pursue it if enough folks are interested.

    I'm mainly concerned with doing some non-driver testing for the research side of things. However, if you are going to suggest a driver, be reasonable. I will only test drivers that are current production. I honestly do not want to spend a lot of time testing drivers that are out of production, even if there is a strong curiosity (ie: the JBL 2118's). For one reason, there's a possibility it will be toasted. I've not done this yet but there's always the potential depending on how hard I push the driver.

    Also, if you have a driver to offer up then by all means, offer it up. If there's enough folks who want to see it tested, we'll see what we can do.


    My current objectives:
    • Tweeter without and with grill cloth to see if the response changes and how much.
    • Use Klippel's SIM module to play with varying the varying LSI measurements to see how each plays in to distortion makeup.
    • Sound deadener testing on a door panel via an accelerometer. Attach the acc to the door panel, measure the response to get frequency magnitude and waterfall plots and then add CLD to the panel and remeasure to see how the resonant modes on the panel itself shift. To me, door panels are one of the highest areas of concern for vibration and localization via buzzing.
    • Break in testing (some of which has already been done). Not just with standard T/S measurements but harmonic and intermodulated distortion. I lalready have one data set on this. I may do a couple more.
    • Measure a baffle with 2 drivers mounted one way vs a push-pull type configuration with one driver flipped around the other way and polarity swapped so they play in phase and see if the resonance of the panel is indeed diminished. This would be done with an accelerometer.
    • Horn/Waveguide study.



    The following drivers have captured my attention for potential testing:
    • Alpine Type-R 10" Shallow Subwoofer. Namely how it performs in a very small box.
    • JBL GTI Mids and MS-62c mids.




    Let me hear your thoughts. I may not have the capability or time to pursue a specific idea but toss it out there.
    Last edited by ErinH; 08-03-2012 at 06:03 PM.
    Your ears: The best tools you have... and they're free, too!

  2. #2
    Tester Extraordinaire ErinH's Avatar
    Join Date
    Aug 2010
    Posts
    1,247
    Regarding the accelerometer testing, my real goal is to correlate door vibrations with what you hear. I will do this by sweeping the system and measuring the door panel movement and the frequency response to see if you can gain more insight in to how the vibration affects what you hear.

    I bought a new accelerometer last week and have been playing with it a small bit.

    Here's a very general idea.
    I sat a driver on a piece of MDF and swept it with 2v, then 5v from 20-500hz. Look at the difference measured on the MDF by the accelerometer.




    What would be interesting is to measure how mechanical issues from a driver affect resonance on a panel but that may be one of those things that doesn't really do much other than look cool. ;)
    Your ears: The best tools you have... and they're free, too!

  3. #3
    Senior Member cvjoint's Avatar
    Join Date
    Mar 2011
    Location
    Northern California
    Posts
    801
    Real Name
    George
    It would be interesting to see the results for vibration canceling LAT technology but alas they are discontinued.
    2001 Honda S2000
    Head: Pioneer P99 + Samsung Galaxy S3
    Amplifiers: 3,000w+ Zeff class G/H power
    4 way: Aurum Cantus AST2560 Air Motion Transformers, BG Neo8-s Planar transducers, Peerless XLS 10" MAC midbass woofers, Tympany LAT700 x2

  4. #4
    Founding Member
    Join Date
    Aug 2010
    Posts
    180
    Quote Originally Posted by ErinH View Post

    I bought a new accelerometer last week and have been playing with it a small bit.
    Replaced the digikey one with what? Is it lighter? What about cost? Just curious.

  5. #5
    Tester Extraordinaire ErinH's Avatar
    Join Date
    Aug 2010
    Posts
    1,247
    same model. my other one was apparently busted. when I wired it up to use it, I got nothing. It sat unused for about 2 or 3 years, I'd guess... no telling when it happened or if it arrived that way.
    Your ears: The best tools you have... and they're free, too!

  6. #6
    Big Daddy Chad's Avatar
    Join Date
    Aug 2010
    Location
    East-Central Illinois
    Posts
    1,570
    build a white-box.

  7. #7
    Tester Extraordinaire ErinH's Avatar
    Join Date
    Aug 2010
    Posts
    1,247
    whoa there, big fella. that dude is dead. gotta chill on the references.
    Your ears: The best tools you have... and they're free, too!

  8. #8
    Controller AL9000's Avatar
    Join Date
    Aug 2010
    Location
    Jupiter
    Posts
    389
    Real Name
    Alan
    What size and types of drivers can you measure? Is there a range?


  9. #9
    Founding Member
    Join Date
    Aug 2010
    Posts
    496
    Why is an accelerometer always preferred as a tool compared to a strain gauge?

    Just curious.

  10. #10
    Tester Extraordinaire ErinH's Avatar
    Join Date
    Aug 2010
    Posts
    1,247
    Because I have an accelerometer sitting in front of me and I don't have to remind myself how to wire it up. I haven't used a strain gauge since I was in my sophomore year in mechanics of materials lab. So, the answer is: money and time.
    Your ears: The best tools you have... and they're free, too!

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •