Tweeter Diffraction Felt Rings

Discussion in 'Speakers' started by NeedForSpeed, Sep 28, 2014.

  1. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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    I have used the Pioneer HPM 100 for many years, Yes we all know the issues, Bright, Lousy imaging, Weigh a ton and a half, Cabinet to small, Etc.
    With a few tweaks here and there(900 tweeter/Mid range, Recap, EQ), They have sounded very nice for a few years. I recently redid the veneer, And while they were apart, I was reading an article written by a guy who designs for Morel drivers, And was on the diffraction subject, And the use of felt around the driver, And even installed on the baffle surrounding the tweeter, And in some cases the mid-range driver.
    I was not prepared to cover my freshly smoothed painted baffles, But thought I would give a spare set of original 100 tweeters the treatment, These drivers are a night and day change from the later HPM line of drivers, In a bad way.
    I went to my nearest craft shop and bought some black self stick felt, They had different thickness's, The article stated no more than a 1/4" and no less than 1/8".
    Installed the covered tweeters(Just the mounting plate, Of course!), And fired everything up. First impression was, Damn, Forgot to wire up the tweeters, They really were tamed down, Did a bit of tweaking on the L-Pads, And boosted the EQ a few steps at a time, And have to say, That tweak really worked, For my application anyway.
    Most of the inherent harshness was cut with adjustments stated above, But the felt gives the speaker more focus is the way to put it I guess. I'm rethinking the felt baffle, Maybe it really would bring these to another level, Stay tuned.
     
  2. cgutz

    cgutz AK Member

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    I have Jensen 24 speakers that years ago the foam ring around the dome tweeter crumbled. It was red color to set off the yellow midrange foam and blue surrounds. I therefore thought it cosmetic. Then I read about felt rings and tweeter diffraction. Put rings around the tweeters and you are correct, audible taming of some of the harshness.

    http://www.audiokarma.org/forums/showthread.php?t=421679
     
  3. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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    Thats what I tried, A shocking difference. did not think it was an issue.
     
  4. doctorolds

    doctorolds AK Subscriber Subscriber

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    What thickness of felt did you use, and have you tried any other thickness?
     
  5. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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    There about 3/8's thick, And mounted them of the mounting plates which on HPM 100's are fairly wide. I did a little A/B test last night, Right side with the tweeter treated, Left side not treated, And it is a big change. Still playing around with the fine tuning, But there staying for awhile.
     
  6. born2tech

    born2tech Active Member

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    cool, im glad you posted this, i will try that , also i have a number of old pc mouse pads and have thought about using them, some are thicker than others, anybody try that before?
     
  7. spkrdtr

    spkrdtr spkrfixer Subscriber

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  8. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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  9. rvatfhunter

    rvatfhunter AK Subscriber Subscriber

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    Never hurts to try something, but mousepads are neoprene, which is not noted for absorbing sound.
     
  10. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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    Right, Wool felt seems to work best.
     
  11. NeedForSpeed

    NeedForSpeed Rock'n And Roll'n Night And Day Subscriber

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    I see the results don't lie, Thanks for the testing, I fashoned mine after the madisound rings I saw on there website, Now thinking mine may not be thick enough, What do you think about stacking 2 per driver, That may be close enough. Thanks, Robert
     

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