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How speaker cone movement should you see in a cab?

Discussion in 'Amps and Cabs [BG]' started by Da LadY In Red, Jul 21, 2008.


  1. So I've played the crap out of my Avatar 2x10 neo for years, and I've finally broke it. I now have the Avatar 2x12 neo as a replacement and am trying to be a little nicer to this cab.

    However, this poses a question: how much are the speaker cones in a cabinet supposed to move? Should it only vibrate a little, or is it okay for them to visibly move around a little bit? Also, should a 12 inch speaker be able to mopve around more or less than the same type of speaker in a 10 inch verson?

    Thanks for the help! I realize this is a decently difficult question to answer in all it's complexity, so a dumbed down, ballpark answer would be more than appreciated!
     
  2. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    It depends on the driver itself. My Markbass 12" moves so far you'd swear it was trying to bust through the grill, yet it's perfectly normal. A speaker will tell when it's moving too far. As long as there's no audible frapping going on, you're fine.
     
  3. Excess speaker travel is is a killer. A couple of things to look at, are the amp's damping factor and if there is a lot of sub sonic info going to the speaker. Some amps have a bass roll off or sub filter that stop the ultra lows but you will notice that your balls are not as happy!
    I have ballooned and popped a few drivers due to too much sub info into the cabinet that had so much back pressure, the speaker surrounds (foam) blew out. The foam surrounds allowed for more sub low end and would sound great at med. output but when you try to get that same thick, rolling low end at high volume..."pop" goes the driver! Hello, 4x10s or 2x10s plus 15" and crossover instead of 2x10s!

    Good luck!

    :bag:
     
  4. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Excess travel is a killer if the driver isn't designed for excess travel. The Markbass drivers are designed for it.
     
    BadExample likes this.
  5. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    ..... which means it's not "excessive" by definition :)
     
  6. the drivers xmax (in the specs for the driver) tells you how far the cone can move before doing damage. it can be anywhere from 2mm (less if it isnt meant to reproduce the lows) to 10mm, and possibly more. depends on the speaker
     
  7. pulse

    pulse

    Apr 10, 2007
    Berlin, Germany
    when I turn on my amp it gives a big click and sends a huge movement through my speaker

    is this dangerous?

    for now I turn on the solid state head with out the speaker connected and then plug it in after it has powered up since it does not make this huge swing in the speaker like this
     
  8. The 12" Deltalite II's xmax is 4.9mm. Xlim is 8.5mm. Xmax is the average of the forward and reverse travel of the cone, or a measure of either the forward or reverse travel of the cone, so you have a total of 9.8mm of movement where you will still get a clean sound out of the speaker and a total of 17mm before you reach it's physical limit. That's a LOT of travel.
     
  9. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I'm unaware of any musical instrument drivers that use foam surrounds. There are a couple of pro-sound subwoofer drivers that use foam, but they are intended for horn loaded enclosures only, if used in a direct radiator cab they have insufficient sensitivity for pro-sound usage. Foam surrounds are common in auto sound and hi-fi drivers, which also have insufficient sensitivity for pro-sound usage. If one attempts to use them for pro-sound they will blow from the power they require to reach pro-sound output levels.
    Xmax is as far as the cone will move before the onset of high levels of distortion. Going beyond that won't give any appreciable increase in volume, but will result in an appreciable increase in heat in the voice coil, potentially resulting in driver failure. Rule of thumb: if the drivers fart out turn it down.

    I doubt that the Markbass drivers have any longer throw than others. The high visibility of their yellow cones probably just appears to move more.
     
  10. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I have no doubt you're right, Bill. But let me tell you, the first time you see it, you freak right out. Well, you probably wouldn't, but I and many others have. Our guitarist thought it was blown the first time he saw its excursion.
     
  11. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    No, they definitely move more. We put this theory to the test in the store against several other cabs and funnily enough it was me who was saying the same thing as you Bill, that the orange cones just make the movement more visible. I had to swallow my pride and on this one. With grills off and my keyring torch for better luminosity on the black cones, the markbass cones clearly moved further.

    They also seemed to move sooner, indicating a softer level of "stiffness " to the suspension, which I'm sure Bill will tell us more about if we ask nicely.
     
  12. Yes, I must say, first time I saw it with my MarkBass I was concerned, too, until I saw this thread.
     
  13. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Moving further, possible, though doing so would also result in their being louder in similar cabinets. As for moving sooner, absolutely not. All drivers respond at exactly the same speed. If they appear to be moving sooner that's clearly an optical illusion, and that same illusion likely appiles to their apparantly moving further with the same output level, all other cabinet factors being equal.
     
  14. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Tick! the MB 410 is audibly "louder" than the Eden 410xlt, and they're the 2 loudest 4x10's in the store..........

    I agree, but think you misunderstood my meaning of "sooner". I meant that if you start with the volume all the way down, and bring the volume up gradually there is no noticable movement from either black or orange speakers until the SPL reaches a certain point. The SPL level at which the speaker movement becomes noticable to the naked eye is lower on the MB then other cabs.To lessen the effect of the optical illusion, we removed all grilles and shined a light on the black cone to bake it look a pale colour.

    From a T/S parameter point ov view, lets assume the MB suspension isn't as stiff as, for example, the Eden's suspension. How would that be reflected in the T/S parameters? Probably a higher X-max, and perhaps a higher QTS for the MB speaker?
     
  15. MarkMyWordsXx

    MarkMyWordsXx

    May 17, 2006
    fwiw my avatar4x10 jumps like crazy
     
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  17. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    They're PA subwoofer drivers, intended for use in a small sealed cab driven by a Linkwitz transform circuit. They're not musical instrument drivers. If SWR did use them as such without the Linkwitz transform it was a misapplication. :(
     
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Using a softer suspension accompanied by a lower tuning the increased excursion compared to a cab loaded with stiffer suspensioned drivers tuned higher would be visible. All else being equal the softer suspension driver would have a higher Qts, so it would have less sensitivity but would go lower.
     
  19. There are many drivers our there. Some are designed to be quite high excursion. You cannot make any statements about how much you see one speaker "move" in comparison to another speaker unless you know how it was designed. For example, you would never put a high excursion driver in a sealed cabinet - you need to let the air move.
     
  20. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The opposite is usually the case. With cabs of equal volume a sealed box has less sensitivity than a vented box, so for equal output the sealed box driver requires longer excursion. The ELF system uses a very long excursion driver in a small sealed box to provide the same output as a standard driver in a larger vented box. The trade-off in so doing is sensitivity, so for that same output an ELF system requires on average four times the amplifier power that a vented box does.
     

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