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DriveRack PX Questions

ManikMekanikManikMekanik Posts: 7
edited June 2013 in Configuration Wizard
I have a mixed setup of subs, one JBL PRX 618 S XLF, one JBL 718S, and one JBL M-PRO 255, and two JBL 615M's for main tops. I just bought a DriveRack PX. Can I use all 3 Subs with the PX? I already did one gig without the M-Pro but would like to use it also at an outdoor gig coming up.

Also, the manual says to set the pink noise to performance levels, I have a db meter, should I go by the meter? And how loud should I shoot for and not be too loud?



  • Has anyone read this?? :?
  • DraDra Posts: 3,777
    There are no problems connecting any number of amp / speakers to an output (within reason). Using different subs can be an issue from a pure sound standpoint. This is less of a problem if all are of the same size and basic design.
    However, you have 2) 18" front loaded cabs and you are trying to add a dual 15" sub that is not front loaded. It is either a manifold, horn, semi-horn, or possibly a band pass box. That is bad news in most cases. The PX has no delay feature, but in your case that would not help sense there are only 2 outputs. You could manually delay (through placement) the 18 cabs behind the M-pro. How far would be trial & error? And to add to the confusion, it will be frequency dependent. In other words, 70hz may benefit, but 65hz may be hurt.

    Performance level is relative. Pink noise can melt a horn driver if using too much power. Just imagine conversation levels (how loud you have to talk to be heard while performing) and use that as a reference.

  • Yes the JBL M-PRO 255 is a Dual fifteen inch band-pass type cabinet, 500 watt/2000w Peak, forgive my ignorance (that's why I'masking).

    So it would be much simpler to leave the JBL M-PRO 255 out of the equation, rather than experimenting with a delay or speaker placement? Would it make my low end sound muddy or un-defined and not punchy? I could also run it from a seperate send with a seperate eq, than from the same send to my powered subs and have more control of it that way, just trying to get the most out of what I have.

    The bands I run sound for usually range in loudness from 100 to 115 db, I was just trying to find a reference point with the pink noise, I know the bands stage volume also contributes to the overall volume, would 95db be too much/little?
    I'm not familiar at all with "pinking" a room. Thanks for the help! :)
  • DraDra Posts: 3,777
    There has been a lot of discussion on the Auto EQ process. Too much to repeat here. Do a search and read. Even check out the former forum link above.
    I will say this. Can it help? yes Can it hurt? YES

  • I don't see a link about the Auto EQ, I will search it. I am assuming I will be better off with all front loaded subs, or all the same type to make it simpler....
  • I'm doing an outdoor gig soon, should I place my subs up on the stage or on the ground to get the best performance?
  • DraDra Posts: 3,777
    Dra wrote:
    There has been a lot of discussion on the Auto EQ process. Too much to repeat here. Do a search and read. Even check out the former forum link above.

    Ground, generally.
  • DraDra Posts: 3,777
    'Bout time. :mrgreen:
  • Thanks guy's, exactly what I thought. I will do some reading now... :)
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