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?