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Thread: Adding cone excursion?

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    Adding cone excursion?

    I have a pair of old school 8" JL IB woofers that need surrounds. If I were to find surrounds that offer more throw, am I risking anything? I understand that tinsel leads and coil coming out of the magnet at high excursion need to be checked, but is there any other reason not to try this modification? I would think that spider will still be the ultimate limiter of how far the cone will travel. I could obviously get some other woofers that have more excursion, but sure as hell it would be cheaper to get a pair of new surrounds, whether OE or aftermarket.

    Thanks.
    Last edited by Mless5; 02-10-2020 at 01:29 PM.

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    DIYMA Janitor SkizeR's Avatar
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    Re: Adding cone excursion?

    Surrounds dont give you more xmax. Coil and magnetic gap do

    Sent from my SM-G975U using Tapatalk

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    Re: Adding cone excursion?

    To add - the surround is more of a guide. You've probably seen a sub pushed beyond it's limits. Just rips the surround off.

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    Re: Adding cone excursion?

    Got it, thank you for the guidance!

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    Re: Adding cone excursion?

    Quote Originally Posted by Mless5 View Post
    Got it, thank you for the guidance!
    Did you miss the humour of Theslaking's post?

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    Wave Shepherd - aka Jazzi Justin Zazzi's Avatar
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    Re: Adding cone excursion?

    Quote Originally Posted by Mless5 View Post
    I have a pair of old school 8" JL IB woofers that need surrounds. If I were to find surrounds that offer more throw, am I risking anything? I understand that tinsel leads and coil coming out of the magnet at high excursion need to be checked, but is there any other reason not to try this modification? I would think that spider will still be the ultimate limiter of how far the cone will travel. I could obviously get some other woofers that have more excursion, but sure as hell it would be cheaper to get a pair of new surrounds, whether OE or aftermarket.
    Thanks.
    If for some reason you increase the travel, you might start stressing the tinsel lead which will lead to failure. If you use a longer-travel surround, it might have a larger roll which changes the attachment point on the cone and reduces your Sd (surface area of cone). If you use a surround with a different stiffness than before then you'll get a different resonant frequency Fs, a different Qts, and a different Vas. Those are the three fundamental numbers when it comes to creating an enclosure. If you increase the throw you also risk allowing the voice coil to leave the gap completely, tilt sideways, and get stuck because it won't slide back into the gap again. If that happens then the coil gets damaged and you'll have to re-cone the entire thing.

    Overall this sounds like a bad idea. I would discourage you from trying to increase the excursion by intentionally using a longer-travel surround. I very much doubt you can "overclock" your speaker in this way.
    Measure with mics, mark with chalk, cut with torch, grind to fit, sand to finish, paint to match.
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    Re: Adding cone excursion?

    Good news is that surrounds turned out not to be an issue, it was a rattle of the plastic insert on the rear shelf that was rattling against the back windscreen some.

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