Sub-octavers & deep filters (how easily will they damage speakers?)

Discussion in 'Amps and Cabs [BG]' started by Golem II, Jul 2, 2002.

  1. Golem II

    Golem II

    Jan 4, 2002
    Macon, GA, USA
    You may have noticed a conversation earlier in which someone here asked whether it was safe to use sub-octave effect boxes and deep filters with Acme bass cabs. I think that person emailed Acme and got a reply from Andy saying that it was definitely NOT safe.

    Common sense dictates that one should not pump sound into a cab if the sound is below the cab's tuning frequency, right? Now, if the fundamental frequency of an open low B is 36 hz (not sure if that's exactly right or not,) wouldn't a low B with a sub octave-pedal put out 18 hz? This is well below the listed frequency response in any cab's spec sheet, except subwoofers like the bag end ELF systems, correct? Yet companies will build deep filters or sub-octavers into their amps (such as SWR and Ashdown, who to my knowledge don't make ANY cabs that are tuned to or are responsive at such low frequencies,) obviously knowing that people might take a 5 string bass and play it with a sub-octaver into a standard cabinet. Shouldn't this logically pose a severe threat to the speakers?

    Was Andy just trying to play it safe by warning against using deep filters and sub-octavers with Acmes? I think the impression that some people got was that Acme cabs are somehow worse at handling these devices than other cabs. If this is true, what makes Acmes so vulnerable? Or, should this warning apply to ALL cabs? In that case, how are you supposed to use these effects and NOT damage your speakers?
  2. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    I think its not a huge issue since you usually arent driving tons of power at that frequency into the cab. Besides the frequency range is really more about what it reproduces, than what is safe to pump into it.

    There are several users of cabs tuned to 50, or even 60Hz that play 5 strings, and theyre ok with it. I wouldnt be, but thats because I am some kind of mutant that would rather haul a massive 2-15" cab around than a 4-10".

    In conclusion, it can harm, but under normal playing circumstances they wont.

    Im sorry for any nonsense I have typed, its 4:49 am.

  3. BigBohn


    Sep 29, 2001
    WPB, Florida
    I believe that it would play that ultra low frequency, but at much lower decibal rate than a higher frequency.

    So, the lower the note, the less volume coming from it.
  4. I am still unclear as to whether Andy was just being overly cautious or what. Anything below 31Hz is useless for me anyways so I usually try to keep a tight reign on things when sweeping any of my synths or filters that low. I don't think you'll find many people using an octaver on their B-string (31Hz BTW.) I do push allot of juice through my two cabs. My Mesa, Eden and now my new EB-MM cabs have all done famously with my sub-heavy dub sound. Are ACME's more fragile??
  5. BlacksHole


    Mar 22, 2000
    Rockville, MD
    I'm surprised by Andy's response. Sure, lots of power/volume with really low notes is hsard on your speakers, but it seems to me that how you set your eq is at least as much of an issue. If you set a pretty steep rolloff at a particular Hz and also take into account that the speaker itself loses efficiency below a certain Hz, then I believe that Andy may have overstated his point just to be safe. It may be in part due to the idea that most people who use Acmes tend to use much higher wattage than the cabinet specs out at.
  6. Wxp4759cb


    Nov 23, 2000
    Kansas City, MO
    You could always just use a filter to cut out every thing below 30hz. Thats what I do.