Speaker Cone Moving?

Discussion in 'Amps and Cabs [BG]' started by jazzbassnerd, Jan 25, 2004.

  1. jazzbassnerd


    Aug 26, 2002
    I was in Guitar center trying a Mesa Boogie Walkabout head though and SWR Goliath Jr III cabinet. When I play any note(especially low e) i could see the cone moving about and inch. It would then vibrate with the string and such. Is this bad for the speaker or is it doing exactly what it was designed to do? Sorry for my un-knowledge of speakers. I also heard a slight distortion, very mild overdrive type sound. The head does hve preamp tubes and I had the gain up about half way, is the tubes what caused this or was a pushing something to hard? Thanks

  2. Petebass


    Dec 22, 2002
    QLD Australia
    Well speakers are supposed to move. But as you saw they can be made to move too far and distort (or worse). There are 2 ways to do this. One is to drive the speaker too hard. Adding bass at the EQ section counts as driving the speaker too hard. The other way to do it is to feed the cab frequencies that are lower than what the cabinet is tuned to (I'm assuming it was a ported cab). The E string has a fundamental of 41Hz. Chances are that particular cab was tuned higher than that.

    Guitarists actually like a bit of speaker break-up. Generally speaking bass players and PA operators want it clean at the speaker.

    If your situation is driving your speaker to it's excursion limits (X-max), then get a second speaker cab.
  3. kaboom133


    Oct 19, 2001
    Latrobe PA
    I hope this isn't highjacking, or anything, but i have a question about the speaker moving like that. I seem to remember seeing the avatar 212 cab was tuned to 50 hz. If the low E string is 41 hz ( I think I'm understanding this) would that mean the speaker would move and distort a little when the low E is played?
  4. Petebass


    Dec 22, 2002
    QLD Australia
    Correct but it's not as simple as that.

    First of all, distortion at low frequencies is harder to hear than mid or high frequencies, especially at band volume. So in a lot of instances you won't even notice until one day you push that little bit harder and the speakers goes "Farrrtttt".

    A lot of commercial available cabs have this characteristic. But cab farts are like human ones in that you tend to ingnor tham and hope no-one noticed. Most guys will upgrade and/or buy a second cab but they'll never admit that the cab they've been raving about has been distorting at times.

    Believe it or not, mand speakers actually hit X-max at a power input which is way below their RMS rating. Speaker manufacturers base their power ratings on the strength of the adhesives and ability to disapate thermal energy (heat). What they don't tell you is that the speaker has hit it's excursion limit long before the glue starts to let go. So i guess they rate their speakers more for X-Mech (physical damage) than X-max(excursion before distortion, but even that is stretching it. In a way that's good because it means speakers don't break down the second we push a bit hard, but it means we buy 700w speakers expecting them to be clean for the entire 700w. The Eminence Delft 12Lf is a 700w speaker that's distorting at 150w. The Selenium 15SW1P is an 800w driver that can take 800w - speakers like that arent common unfortunatelly. They're also not cheap and if you're buying Avatar, chances are price is a big deal to you at that time.
  5. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay

    Damn, nothing left for me to say.

  6. Petebass


    Dec 22, 2002
    QLD Australia

    But, But, But, he asked and I answered and I'm sorry...... I'll shut up now. You guys just chat amongst yourselves or something......