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Sub Virgins

Discussion in 'Live Sound [BG]' started by nanookofnj, May 19, 2011.

  1. nanookofnj


    Oct 21, 2010
    We've been running our own sound for the last 5 years at venues we play that don't have built in PA's. Our PA is two powered Mackie SRM450's as mains on poles to which we run a signal from a Yamaha 2x500 powered mixer and also run a powered signal to 2 12" monitor wedges.

    Currently running as a 5 piece. 4 vocals, drums, keys, bass, guitar, and pedal steel.

    We just picked up a new 1000W powered 18 Mackie sub to compliment the SRMs in hopes it would allow us to mic the bass drum and run bass thru the board as well. It has a built in Xover, so thinking it should be pretty much plug and play.

    Is there anything we need to watch out for or to take into consideration when setting up with the new sub? Thanks in advance.
  2. Don't plug a powered out from your mixer into it. :D

    Entirely your choice on using the full / high pass outs from the sub, but I would suggest daisy chaining your high packs out from the sub.
  3. +1, mixer>subs>tops.
  4. marklaforest


    Feb 5, 2010
    Good call on the mackie. Best sub in that price range by a long shot for a working band. Anyways, one thing that really helps with a sub is to run it out of an AUX send from your mixing board. Then you can send specific things to it and leave other things out of it.

    You'll wanna send bass, kick, toms and such through the sub. But leave vocals and guitars out. This will make the sub kick a lot more ass, and also leave much more power in the mains for vocals and guitars. Make sure you also send your bass and drums through the mains too though.
  5. chetorch

    chetorch Guest

    Apr 13, 2011
    interesting, is there a particular reason for this? I actually do the reverse of that and feed a signal from the high pass to the sub.
  6. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Yeah, we have all powered mains and subs and, since we run a mono mix, we just daisy chain the mains off the sub using its built-in crossover. It's also possible to use a separate crossover. I have occasionally used a dbx Driverack 260 for that purpose.
  7. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    By going to the sub first, it strips everything below 100 hz or so from the signal, so your mains are not getting the low-frequency content. They're no good below about 80 hz anyway, so you don't want the low frequencies going to them. Having the sub frequencies in your mains robs them of power that would otherwise be used for amplifying the frequencies they were designed for.
  8. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    I can't really see doing that as it needlessly burns a monitor mix AND makes makes the overall mix more difficult to manage - more knobs to touch. These is an active crossover in play and it is all that is necessary to optomize what is going to the tops and what is going to the subs.
  9. This.
  10. jaywa


    May 5, 2008
    Iowa City, IA
    Excellent suggestion. No reason for guitars to be running through the subs, especially considering 9 out of 10 gui****s run WAY too much low end on their tone the way it is.
  11. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    If you use the crossover in the sub, it will automatically do what you're saying. The only instruments that produce frequencies below 100 hz are the bass, kick and toms. It will also pass the high frequency components of those instruments to the mains, again without unnecessarily burdening the mains with frequencies they're not designed to reproduce.
  12. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Not that excellent. See above. If you use a crossover, the guitars won't be in the subs anyway (well, their E string at 80 hz and up might be in there a little bit). By the time you get on their A string at 110 hz, they're not in the sub at all. You could also use a crossover set at 80 hz, with a steep slope like 24 db per octave (fourth order). That'll keep the scurvy bastriches out of the subs.
  13. jaywa


    May 5, 2008
    Iowa City, IA
    What I like about the separate-send idea is that it gives you extra control over just the low end of the mix. For example, if you start a show with a sparsely populated room and by the end of the first set you have 200 bodies in there sucking up bass, you can pump up the sub(s) and restore the bottom to the mix rather than having to crank up the whole mix (and risk the top end getting too shrill).

    But, as already noted, that takes away a send that could be used for effects or monitors. So as with virtually everything P.A., it's a question of tradeoffs. And, with the OP's band running sound from the stage, a separate level for the subs is one more variable they probably don't need and may not want to deal with.
  14. Phat Ham

    Phat Ham

    Feb 13, 2000
    You'll still get bleed into all the mics. Yes you can high pass them but on most boards the attenuation is only 12 dB/octave or even 6 dB/octave and on the cheaper boards the high pass is preset pretty low at 80 Hz or 100 Hz. Like others said it uses up an aux and you may need another crossover channel or two.

    To the OP I wouldn't worry about this too much. If your mixer has high pass filters on the channels I would engage them on everything but kick, bass, and floor tom (and maybe keys if you have them).
  15. Wow you my friend are really ahead of your time here and will be chastised I'm sure. I read about this years ago in a Mix magazine or whatever. A very well know FOH person was interviewed and he suggested it. As soon as I had the gear I started doing it and man did it clean things up. I can't argue with the crossover cutting stuff, I know that is how they are supposed to work but using the Aux trick for bass, kick and other low end hungry items really cleans it up (keep the gtrs away). Also another beni is that if you feel you need more real bottom you can crank up the aux to the sub w/o having to crank up the whole system. Inversly if there is to much woof start by backing off the sub. It is even better to put in a decent graphic dedicated to that aux for fine tuning.
  16. nutdog

    nutdog when I'm a good dog they sometimes throw me a bone Supporting Member

    Feb 19, 2009
    in the dog house
    Wouldn't this require a separate crossover or hi-pass for the mains? How does it leave more power in the mains if you are also sending the drums and bass to the mains?

    We use this same set up with JBL mains and Mackie sub. We go mixer>sub>hi pass to mains. Like you say, plug and play.
  17. We have always ran our sub off of an AUX send at my church. I remember for a little while we had everything running to the sub and speakers and we would get nasty feedback some times.

    I've EQ'd everything below 100Hz out of the mains so that they aren't being pushed too hard.
  18. Jazzdogg

    Jazzdogg Less barking, more wagging!

    Jul 29, 2006
    San Diego, CA
    I use a MixWiz 16:2 utilizing aux-fed-subs, with two separate mono output signals: one high-passed to the mains, and one low-passed to the subs. I like being able to change the level of the mains and subs separately using only two faders.

    Using this method, I could not feed a single ouput into a sub's built-in crossover and thence to the mains; I'm currently routing the two signals into a rack-mounted crossover on their way to separate amps for mains and subs.
  19. The internal crossover on those subs is 120Hz IIRC; it's a little high, but it lets you push the system a bit harder before the tops start complaining.
  20. jaywa


    May 5, 2008
    Iowa City, IA
    My church does this too. I think it's so they can kill the bottom end when the old folks start getting restless :D

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