Running dual 15 tops close to full range and then addind a sub.

Discussion in 'Live Sound [BG]' started by troy mcclure, Jan 6, 2013.


  1. troy mcclure

    troy mcclure Supporting Member

    Joined:
    Mar 5, 2007
    Location:
    Central Florida
    I have been crossing over my system at 120 to my 18 subs. A buddy of mine said " you have dual 15's in your mains..use them."
    As I run in mono, I could use the other side of my stereo crossover and bring the mains (JBL MRX 525) in at a lower frequency than 120. I was thinking 65-75.
    Will I have problems. Most gigs I can't double stack the subs but I have about 20 -25 ft between them and of course the mains sit on top. I really want to build some stands for the mains and center the subs, but most gigs the stage is to low. I have corner loaded them and it seems in a wide bar, the subs are only good on the side I corner load them.
  2. Floyd Eye

    Floyd Eye

    Joined:
    Feb 21, 2010
    Location:
    St. Louis
    Currently we are running out of a crossover into 2 18" subs, 2 2x15 (JRX) cabs and 2 12" Yamahas. Sounds real good. I don't know what crossover frequency our sound guy is using. 100 I think.
  3. Floyd Eye

    Floyd Eye

    Joined:
    Feb 21, 2010
    Location:
    St. Louis
    Incidentally we almost always put 1 sub and one of each cab on either side. Most places we play it isn't feasible to cluster the subs.
  4. walterw

    walterw Supportive Fender Gold Supporting Member

    Joined:
    Feb 20, 2009
    until you get tired of lugging those silly things around, try crossing over way lower, like 80-90Hz and see if that lets the bottom 15 actually do any work.
    huh?

    mixing top cabs is probably worse than mixing subs, especially when you put them side by side so they comb-filter!

    i suppose if they were spread out so each top cab was only covering its own area it would be OK, but they should never "overlap".
  5. Hactar

    Hactar

    Joined:
    Sep 25, 2011
    Location:
    Boulder, CO
    You'd probably be better of replacing the 2x15s with a decent set of 1x15 tops. Easier to carry around.
    There's not really any sense in having 2x15s with subs.
  6. troy mcclure

    troy mcclure Supporting Member

    Joined:
    Mar 5, 2007
    Location:
    Central Florida
    I did want something up top that could handle vocals and highs better than 15's. I actually wanted 10's or 12's. The problem is speaker marketing. Dual 15's will go pretty low and handle way more power than dual 12's or 10's in a midrange price line like the MRX series...I got a great deal as they were discontinued. JBL doesn't even make a double 12 until the SRX series which are like $1800. I looked at a bunch of different options and for the money this was the way to go. I almost went with the Carvin TRX with 2 10's but they were too small height wise.
  7. walterw

    walterw Supportive Fender Gold Supporting Member

    Joined:
    Feb 20, 2009
    a great deal on the wrong piece of gear is not a great deal at all.
    that's why they would go up on stands or poles! something like that, where you could get the horns over the crowd, with real subs to handle real sub duty, and you'd be in business, and with an easier load-out to boot.

    on top of that, with separate speaker stands for the tops your subs would be free to be center-clustered whenever possible to greatly beef them up, too.

    (oh, and 15s can do "vocals and highs" just fine! in an otherwise similar box, you get a little more volume than a 12, but with a little narrower pattern; that's something i don't mind, so i can keep my band loud in front of us on the dance floor but maybe not so loud at the bar.)
  8. Floyd Eye

    Floyd Eye

    Joined:
    Feb 21, 2010
    Location:
    St. Louis
    I'm sure you're right. We have them stacked on top of each other. Believe me, none of this was my idea, but a lot of people have said it sounded real good and from my forays out front I thought it sounded ok. I have a question though. If we are putting bass and guitar into the PA as well as drums and vocals, are you saying that we would be better off just using the 12" Yamahas ( obviously the subs as well)?
  9. troy mcclure

    troy mcclure Supporting Member

    Joined:
    Mar 5, 2007
    Location:
    Central Florida
    yes he is, the subs carry the lows and 12's will carry everything above....if I read his opinion correctly.
  10. Floyd Eye

    Floyd Eye

    Joined:
    Feb 21, 2010
    Location:
    St. Louis

    That's originally what I told our sound guy ( admittedly he is not the best I have heard and we are in fact getting more and more disappointed with him), but he was convinced that with the bass in the PA we needed the extra speakers. He brought in the JRX cabs ( I would not have bought these) and the 4000 watt poweramp to run them. I suppose I might have been blinded by the fact that my bass sounded better to me coming out of these cabs than simply coming through the 18"s.
  11. walterw

    walterw Supportive Fender Gold Supporting Member

    Joined:
    Feb 20, 2009
    it doesn't work that way; bass guitar would come through the subs and the tops, just like the other instruments with lots of lows in them (kick, toms, maybe keys). the crossover sends the lows from everything into the subs, and the mids and highs from everything into the tops. (yeah i know, "aux-fed subs"; a different topic!)

    i'm just saying that mixing different kinds of top cabs, especially side-by-side, is strictly garage band.

    whichever set of two tops is better, use those and leave the other two at home.
  12. modulusman

    modulusman

    Joined:
    Jan 18, 2004
    Location:
    montana
    The JRX 125s are the worse sounding speakers that JBL currently makes IMO. The clueless buy them because they have a JBL badge.
  13. Oddtime

    Oddtime

    Joined:
    Nov 22, 2011
    Location:
    Bay Area & The Midwest
    Troy,

    Do you have an opportunity to set-up and do some listening tests with the band and some of you favorite recorded material with the crossover set at different positions? Are you running everything through the PA? Other people have already commented on not mixing the tops...always sound advice! How are the speakers typically set-up on stage? Are you always placing them side by side?

    I just recently added the FOH main set-up to my PA gear and really put a lot of time into researching what the tops and subs would be. As the goal was to run everything through the PA 95-100% of the time and having a clear and articulate vocal up over the top was important, I went with (2) QSC KW181 Subs each with one KW122 on a pole. I felt the dispersion was better with the 12" and the distribution between the subs and the tops would work best. I did not want the tops to be tasked with providing too much in the lower frequencies. This speaker set-up is being run through a Driverack 260 and I also have a rescue DBX 1231 dual-band graphic EQ inserted before the Driverack to make any changes quickly during the show without getting into the screen and fussing about. This is not a big array that looks intimidating...however, it is a set-up that is plenty powerful and delivers a BIG sound that is tight and defined with an easy load-in and quick set-up.

    Too many of the shows I have been to had the mains (tops) working overtime and the mix was not articulate...there are/can be many reasons for this, I understand. However, when I spoke to the sound man or the band members, many of the acts had the mains set with very low crossover frequencies.

    I would offer that you absolutely re-consider your current crossover frequency and without fanning the fire too much, replacing your mains as well with smaller boxes. I promise that your sound will be dramatically changed and the mix can achieve a far better balance and sound-field.

    In addition to playing your instrument better and growing as a musician, this is a whole other world to learn, refine and grow into...doing your homework and listening carefully is paramount to a good sound!

    Best of luck!
  14. KingRazor

    KingRazor

    Joined:
    Jun 4, 2010
    Location:
    Beaverton, Oregon USA
    You're using subs. Ditch the dual 15s and get a couple of 12s. Let those subs do what they're meant to do.

    IMO, YMMV.

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