Drivers need break-in after dormant periods?

Discussion in 'Home Theater Projects' started by Michael R Price, Sep 25, 2003.

  1. Michael R Price

    Michael R Price Screenwriter

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    There's some sort of consensus that speakers sound better after they are run in for at least a few hours. But I was wondering if it's possible for the drivers to become "stiffer" again over time. I've started noticing this effect, where my Kit281s will sound fine at low 'usual' volumes (all the time). But when I start to push it once in awhile, there's a weird distortion, sort of like harshness... it's just less clear and generally unpleasant. Sounds like speaker distortion to me. I think, wait a second, aren't these supposed to go to 105db?

    I'll leave the room for maybe 10 minutes, and when I get back, the sound is better, the distortion is for the most part gone and it sounds a lot more like it does at lower volume. (With the exception of being even more awesome, that is. [​IMG]) A possible explanation is that my speakers, darned AV8 woofers especially, are degraded in some way over time when they're not played loudly.

    I thought of this because I recalled some measurements (see http://www.audioasylum.com/audio/spe...es/137278.html) of some woofers that exhibited large changes in T/S parameters from a "new" state to being broken in. Perhaps those revert a little bit towards the original parameters when the driver is not used. Those changes could go away after a shorter period of heavy use relative to the initial break-in.

    Does anyone know if this is reasonable, or just total bullhockey?
     
  2. RichardHOS

    RichardHOS Second Unit

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    A deteriorating foam surround might have "set" induced stiffness. Not sure about that one.

    Heating of the voice coil produces a change in Qts and system Q, which in return changes the frequency response.

    The resin impregnated cloth spiders typically used shouldn't have any "set" induced stiffness changes that I can think of.


    Hmm... that about covers the possibilities as I see them.
     
  3. DanWiggins

    DanWiggins Second Unit

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    Heating of the voice coil, or ear overload may be the issue. I've never seen phenolic spontaneously re-flow once broken in...

    Dan Wiggins
    Adire Audio
     
  4. Michael R Price

    Michael R Price Screenwriter

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    Ok thanks. I'm still confused, but I'll figure it out eventually. For now, the sound is good. I thought it was my ear getting used to the loudness but the same thing happened when I just left the room for awhile and came back without listening. I hadn't played loud music in a couple of months.
     

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