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when is a subwoofer needed?

Discussion in 'Live Sound [BG]' started by hgregs, Mar 4, 2013.

  1. hgregs


    Sep 25, 2008
    ct/ny border
    so my band is not entirely sold on the concept of getting a powered sub. i feel like i'm arguing with a brick wall. they all agree that improving the sound is important, but not at all sold on needing a sub.

    our PA has done a spectacular job so far: 2x qsc hpr12s as mains, and k12/k10s as monitors. we have 2 drummers, bass, keys, 2 guitars, 3 singers.

    we had 140+ people at our last gig, and our soundguy said our mains just couldn't handle it. that we need a sub. i immediately started shopping and trying to get band support to buy a ksub. i was immediately met w/ "do we really need it?"

    to their defense, we've played this specific room before. we've played all our indoor gigs without a sub. this was the biggest in terms of # of ppl, but at the end of the day, we're still doing smallish bars.

    they also argued that: isn't there enough bass coming out of my amp? to which i replied - my amp (dually/1500w power amp) has more than enough headroom. but we're supposed to keep a moderate stage volume. plus we need to get keys and kick lows out of the fullrange mains to let them do their job.

    anyway - can you guys help me? tell me some rules of thumb (# of ppl) or something about when a sub is required. something i can point them to read. anything. or tell me i'm wrong so i'm not fighting this fight in vein.

  2. Steve Dallman

    Steve Dallman Supporting Member

    My PA uses rather small cabinets...four single 10's and horn. They've performed well, even for outdoor gigs. I use two small subs, single 15's. I drove the subs from an Aux send, and only put bass and kick into them. It worked fine.

    Then our guitar player bought some powered QSC's, a new mixer and one sub. The sub is a stand for one of the mains, and carries the kick. At outdoor gigs, we do put the bass and guitar into the mains, so the sub carries the low bass.

    Most of the time, only vocals and kick are in the PA and the sub is only for kick. We trigger the kick and use a nice, consistent kick sample that sounds great in the PA without the feedback and instrument bleed problems with a kick mic.
  3. lokikallas

    lokikallas Supporting Member

    Aug 15, 2010
    los angeles
    Kick and keys. That's all that needs to be said. It's not just for bass, as you say, your amp can handle that, but the kick shouldn't be wasting watts in the mains. Keys can destroy mains very easily. You sound guy was right. You may not need anything crazy, but a little sub can go a long way to clean up the mains by running them more efficiently.
  4. tbirdsp


    Sep 18, 2012
    Omaha, NE
    I agree that it's mainly for the kick drum. Personally I'd use at least the one 15" powered sub I have for anything above a coffee-house gig.

    We play a small bar near my house and I run kick, snare, bass, guitar and keys through the mains.

    It really baffles me that many musicians seem to think it sounds OK without a sub. I've heard a few bands that can pull it off, but they are in the extreme minority.
  5. RedMoses

    RedMoses Supporting Member

    Jul 4, 2012
    Your Bass amp is meant for you and your band memebers to hear you, the PA Sub is meant for everyone else in the crowd to feel you. If you get a sub, your PA wont have to work its ass off so hard to support the Bass, leaving it running more efficiently and able get the crowd to hear the rest of the band without it being pushed to its limits. At some point and most likely soon as your gig sizes grow your PA will give out because its been working so hard and then you will sound like a Junior Varsity band that has a weak PA instead of a seasoned band of Pro's providing hours of solid entertainment worth every penny spent.
  6. +1 on that

    Sorry, I can't offer any source of info or rules of thumb you can point to and I'm not an expert by any means, but I can commiserate some.

    Your situation is different, but it makes my laugh a little at my own band dynamics and the subwoofer battles I've been in. There is an aspect that feels familiar in that I was pushing for a sub in my old band, and the rest rest of the guys felt that it was would only be benefiting me. It sounds like you might have a little of that going on.

    With my new band, they've always hired pa when no house sound was available. It looks like we're going to be getting some smaller bar gigs too, and it'll make sense to put together a band pa. The latest battle is trying to convince them that one 15" sub can handle anything up to the point that we're hiring pa. They're unfamiliar with the idea, so it seems wrong to them. I googled and search high and low but couldn't find anything to put in front of them.

    Like lokikallas was saying, one benefit is to the mains, and so the overall sound. It doesn't have to be loud, nightclub thumping sub bass. A buddy of mine has a 3 piece band that always impresses me. They play a lot of small bars and do exceedingly well at playing at levels that allow conversation. I think a lot of people would say "What the hell are you doing micing drums in this small of a venue?" But they run guitar, bass and kick through the pa at very low levels. They have a single 12" sub, and they just get this killer, rich sound. It's not louder, just better.
  7. tbirdsp


    Sep 18, 2012
    Omaha, NE
    You are right on the money with this:D


    You can see the sub with one main on a pole next to me, other main is in the upper left on a stand.

  8. testing1two

    testing1two Supporting Member

    Feb 25, 2009
    Southern California
    The benefits of subs cannot be overstated. Here's the rule of thumb for your bandmates: every professional PA system has subs. Period.
  9. carvinbassplyr

    carvinbassplyr Supporting Member

    Aug 10, 2007
    Waterford, MI
    Subs are not a # of people issue, they're an amount of sound pressure issue. Any system regardless of crowd or venue size can benefit from a proportional sized/mixed sub. By dedicating an amp and driver(s) to handle the low frequencies (push air) you don't have to push the full range speakers as hard to move the same amount of sound pressure. The result is more control over the bottom end of the mix and cleaner, more efficient main speakers since you can set the level and eq of the subs and mains separately (if you set it up that way). Make sure you have a good crossover though because a full range speaker+full range sub or even a full range speaker with only a low pass on the sub can equal a lot of mud.
  10. carvinbassplyr

    carvinbassplyr Supporting Member

    Aug 10, 2007
    Waterford, MI

    Yep! Honestly I don't like a ton of my bass coming from of the subs, it gets too boomy. Subs are to be felt not "heard" IMO. Mixes with subs crossed over @ 150hz and driving 80% of the bass player's tone through them sound like garbage IMO. Use the subs to give the kick a nice thump and maybe add a LITTLE bit of depth to your bass and keys. Careful though, the more bass (whether it be bass guitar, synth or keys) you pump through your subs the less clarity your kick will have because the driver is to busy moving to produce the constant bombardment from the other instruments.
  11. modulusman

    modulusman Banned

    Jan 18, 2004
    My band ALWAYS uses subs. If I was the OP I would get either a QSC KW 181 or if you can find some used QSC HPR 181 or 151. They are probably a better match for your tops.
  12. jchrisk1

    jchrisk1 Supporting Member

    Nov 15, 2009
    Northern MI
    Not trying to hijack this thread, I just have one question since we're on the topic.

    What frequency works best to run a sub?

    I borrowed a pair of subs and a crossover from a dj friend and used them, but I thought they were too club sounding. Not wanting to mess with his stuff, I left it alone and turned down a bit.
    Using mostly just kick (bass if needed) in a rock situation.
  13. carvinbassplyr

    carvinbassplyr Supporting Member

    Aug 10, 2007
    Waterford, MI
    Somewhere around the 80-90hz area IME. It depends on how much "thump" the main speakers have. Mains with larger drivers produce more low mids and vice versa so that moves the ideal x-over point around a bit, but it should still fall within (or around) that frequency area.
  14. jchrisk1

    jchrisk1 Supporting Member

    Nov 15, 2009
    Northern MI
    Thanks. That will get me in the area. Then I can go from there.
  15. carvinbassplyr

    carvinbassplyr Supporting Member

    Aug 10, 2007
    Waterford, MI
    You should be able to find a point where the subs seems to "overlap" the lows of the mains too much (will sound a little boxy/muddy), which means the x-over is set too high. Then you should find a point where there seems to be a "hole" between the response of the mains and the subs (sounds thin, without punch), which means the x-over is set too low. Once you're in the ballpark, then you just find the balance of filling in the sub without overlapping the mains too much.
  16. ggunn


    Aug 30, 2006
    Austin, TX
    A slightly different slant on things: buy it yourself. Band-owned equipment stories almost always end badly. The band should pay for damage to gear, should it occur in connection with a gig, but IMO equipment should be owned by individuals.
  17. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    all that needs to be said.

    if this band wants a full, warm, ear-pleasing sound, they need to cover that missing bottom octave that speakers on sticks just won't get. anything less is garage band or "old folks home" band :cool:
  18. lowfreq33


    Jan 27, 2010
    Endorsing Artist: Genz Benz Amplification
    You can get a passive sub for around $200, and a 2x300w amp (that you can bridge for usually 540w) for about $300. No reason not to at least have one sub.
  19. jaywa


    May 5, 2008
    Iowa City, IA
    If you've got a kick drum and an electric bass in your band... and you want to sound professional... you need a subwoofer.

    Nothing sends me out of the room faster than a midrange heavy band with no bottom end.
  20. Sub every gig. We use a small PA - Yorkville powered mains with 12's, and one sub. Taking the lows out of the main speakers hugely increases your punch. Keys, kick, toms, and bass go to our sub. If I wanted to increase our overall volume level, I'd add another sub.

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