How much speaker movement is normal?

Discussion in 'Amps and Cabs [BG]' started by Brendan, Sep 6, 2001.

  1. Brendan


    Jun 18, 2000
    Austin, TX
    Well, I've cranked up my amp, you know, for concert level volumes (and, just to see how loud it gets), you know, for a limit test. Gotta know the limits of your equiment. Now, my D-410XLT's speakers get moving, but I need to knwo how much is normal, and what is damaging to the speakers. I wouldn't gauge the movements at much more than maby .1 cm, or less than half an inch when I get on the lows (D,A). How much is normal, how much is too much? I keep it fairly quiet, so I know there's no damage yet, but you know, I'd kinda like to know...
  2. Nothing more than an inch. Well, it doesn depend on the size of the speaker, but more than an inch on 15s or smaller can damage the magnets, knock thme loose from their housings. If you have more than 1/2 and inch on an 8, it's toast.

    Rock on
  3. Brendan


    Jun 18, 2000
    Austin, TX
    Well...and that was pretty darned cranked...which, I guess means I can get that thing loud enough for some metal gigs. Thanks Eric...
  4. Luis Fabara

    Luis Fabara

    Aug 13, 2000
    Ecuador (South America)
    Audio Pro - Ecuador
    I believe it depends on the size of the Coil on the speaker rather than the size of the speaker.

    For example: a 8" Speaker with a 4" Voice coil, could handle very low frequencies at high presure levels without a problem. And its excursion would be very high.
    Coil is what gets damaged, not magnets, as far as I know.
    I could be wrong.
  5. The huge coils on Eden speakers are the reason that they get such awesome lows. The excursion you're describing is nowhere near the limit and you're in no danger of destroying the cab. Now, if you had a 2000-watt power amp bridged into it and you were slapping open low Bs all day, you might destroy the voice coil, but for now you should be fine.
  6. You would be best advised to write the manufacturer and ask them.

    To the best of my current knowledge, Eden does not publish the Xmax values for their speakers. This value is the maximum amount of one-way cone movement the speaker has while maintaining full control over the voice coil. Xmax is shorter than maximum excursion, which is that distance where the cone hits the stops or other mechanical restraints.

    JBL 2242's are rated with an Xmax of .3200" but JBL publishes a maximum excursion of 2.0 inches for these drivers. The average Xmax of all speakers I've catalogged so far is approximately .25". An educated guess based on this average would say your cones should move no more than 1/2" total.

    Ask Eden. The warranty will probably be void if the speakers are over driven, and this will be obvious when they are serviced.
  7. Brendan


    Jun 18, 2000
    Austin, TX
    Unfortunatly, I bought used, and the warranty is nonexistant, unfortunately.

    And Analogkid9...thanks for alleivating my fears on that. It does make sense that a cab designed to handle 700 watts could handle all a 300watt amp could put out.

    My bad. Just don't wanna hurt the Eden. That would be baaaaad.
  8. MikeyD


    Sep 9, 2000
    Not really true. You can certainly damage a woofer with far less than its rated power if you drive it with very low frequencies or big transients (such as slap attacks). If the frequency is low enough, even 300 watts could cause the drivers to reach their excursion limits. It is appropriate for you to be concerned about it.

    There is no single number (such as wattage) that will help you avoid mechanical damage in all cases, especially if you are driving the speakers with low bass content. The low B string and/or aggressive attacks are particularly troublesome.

    What I do, when exploring "uncharted territory" (volume/frequency) with my system, is pay a lot of attention to cone movement. The first time I hear the cone bottoming, I look at how much the speakers are moving, as well as my amp settings and what signal (note, attack) caused it. Then I make every effort to avoid repeating the condition.

    Despite my attentiveness, one of my 10" drivers developed a coil rub even though I never drove it to its claimed power handling (and never did hear it bottom). I believe it was caused by running it at fairly high power with bass content below its 60-80 Hz. practical LF response. Since that time, I have inserted a high-pass filter into the amp channel that feeds my 10s in order to prevent such damage.

    - Mike
  9. hmm.. if i turn my amp up to 90%, and strike a B-string, i almost blow out my windows, but my speakers don't seem move even 0.5cm...

    the eden CX410 is really tight.. i've never seen the speakers bounce up and down..
  10. Small cone movement on the Eden near low B does not suprise me. At the port tuning frequency, nearly all the radiation comes from the port, and almost none from the cone. Cone motion is at its minimum at the tuning frequency. Below the tuning frequency is when cone movement reaches maximum and notes played hard below this point can blow your drivers from over excursion.
  11. I think a big part of it has to do with the basses you run through it, too. I hate the sound of most neck-throughs, and since the fundamental really isn't there on your average bolt-on 5, I don't have to worry too much about super-low notes blasting the coils.