Splitting cabs on outdoor gig

Discussion in 'Amps and Cabs [BG]' started by denton57, Oct 12, 2021 at 10:00 PM.


  1. If memory serves correctly, by separating two identical cabinets, you would also be giving up 3db of output from your system.
     
  2. dBChad

    dBChad

    Aug 17, 2018
    Daytona Beach, FL
    It's cool that the guitarist wants to hear more bass! You seem to have found the elusive unicorn team-player guitarist!

    I would suggest tackling this similar to how FOH engineers attack low frequency sound production. If your drummer is on a riser, center your cabs side-by-side upstage center. I prefer to cluster my FOH subs in a wide, tightly-packed line under the stage. One of the promoters I run sound for usually sells advertising space on the stage skirts and puts a contract clause in preventing any visual obstruction of the stage skirting. On these events, I have to split my subs stage left and stage right. It still works, but in a much smaller area than a center cluster. I'd imagine very similar results, as I typically only feed kick drum, keys, and bass to my subs anyway.
     
  3. lfmn16

    lfmn16

    Sep 21, 2011
    charles town, wv
    That's all I need to hear ... NO, NO, NO, NO. :D
     
  4. denton57

    denton57 Supporting Member

    Nov 1, 2005
    Arkansas
    Very interesting feedback. The graphs are great, as I was thinking there might be some drops in volume at oddly close proximity to the cabs
     
  5. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    I've tried it many times with several different cabinets, it doesn't work for my ears. The further the cabs are apart the more delay you'll experience. I've tried it with cabinets as small as the old VL 108's and as large as VL 208's.
    If you have a decent P.A. IMHO that's the way to go. Just my take.
     
    SoCal80s and denton57 like this.
  6. monkeyfinger

    monkeyfinger Moderator Staff Member

    Low frequencies work best when they are coming from a single point. Individual monitor mix with some bass, high-passed at around 100 Hz, in the guitarists monitors should do the trick.
     
  7. Hounddog409

    Hounddog409

    Oct 27, 2015
    ohio
    I always split my cabs. Use a Mesa D800 with 2 1x15 cabs. One on each side of the stage.

    Key is to get them up off the floor.
     
  8. Is it doable? Sure. Will it sound good? Depends.

    The problems have nothing to do with being indoors or outdoors. They are caused by the phase cancellation caused by one cab being closer to each listener than the other cab. This is more prevalent in low frequencies because the wavelengths are longer than higher frequencies. This does not mean that it will definitely sound horrible, it may even sound passable, but the audience won't be hearing your best sound. For best sound: spend your money on subs for FOH and monitors for the band.
     
    Ric Vice likes this.
  9. JacklegBass

    JacklegBass

    Jul 4, 2004
    Not to make people's heads explode, but back in the day I would sometimes run my two Acoustic 370/301 stacks one on either side of the drummer. Despite the double whammy of reading for years here on TB how horrible 18" folded horn cabinets sound and how you should never run drivers in anything other than a vertical plane, somehow I ACTUALLY LIKED IT!!! Sounded great to me.

    Humble Pie's Greg Ridley ran four Acoustic 360/361PP cabinets, two on either side of Jerry Shirley's drum kit. All I remember is getting pummeled notwithstanding the theoretical cancellation.
     
    Last edited: Oct 13, 2021 at 6:35 PM
  10. projectapollo

    projectapollo Supporting Member

    Aug 12, 2009
    Tennessee
    I play bass. I am a home theatre enthusiast, as well. For indoors, the home theatre folks discuss the disadvantages of a single bass point source - creates uneven bass throughout the room. The answer is to place multiple subwoofers in strategic locations. I'm not sure why this principle doesn't hold for bass guitar cabinets used indoors.
     
    JacklegBass likes this.
  11. monkeyfinger

    monkeyfinger Moderator Staff Member

    In general, when you are setting up a room for audio playback, you are always in the optimal listening position. For live, this is rarely true. Listeners are scattered all over the place.
     
    Ric Vice, SoCal80s and trevcda like this.
  12. JacklegBass

    JacklegBass

    Jul 4, 2004
    I run two subs in my HT setup for this very reason. Really smooths out the response around the room. I used to run a Lexicon MC-12 processor that had a low frequency enhancement mode option in its Logic-7 software that would do a phase shift between subs. That helped smooth things some. It was cool, but I don't miss it.


    For home theater in a family room setting the opposite is true, you have to overcome room nodes in multiple positions.
     
    Last edited: Oct 13, 2021 at 6:39 PM
    projectapollo likes this.
  13. @denton57

    Having read the responses, it is clear that the definitive answer is yes, no, maybe. :laugh:

    Best wishes.
     
  14. Wasnex

    Wasnex

    Dec 25, 2011
    Maybe @DukeLeJeune will comment and clear it up...pun intended ;).
     
  15. Ric Vice

    Ric Vice Supporting Member

    Jul 2, 2005
    Olivette, Missouri
    Isn’t that always the case :) Reaching a consensus on Talkbass is like hearing cats.:roflmao:
     
    Peter Torning likes this.
  16. Bassamatic

    Bassamatic keepin' the beat since the 60's

    YES - You will get phase cancellation at some frequencies related to the distance they are separated. If they are not too far apart the frequency may be high enough you don't notice.
    NO you don't lose level by separating the speakers.
    HT - A good way to set up your home theater subs is the put the sub in your seating position and move around the room until you find the best sound, then put the sub(s) THERE. This lets you work WITH the room instead of fighting it. Using multiple subs is really aggravating the problem.
     
  17. DukeLeJeune

    DukeLeJeune rational romantic mystic cynical idealist Commercial User

    Nov 24, 2008
    Princeton, Texas
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    The bass problem in home audio/home theater rooms (i.e. "small" rooms) is that the modal density is too sparse; there are too few peaks and dips, spread too far apart. We can re-arrange the peaks and dips by moving the subwoofer or moving the listener, but we cannot eliminate them by positioning alone.

    I manufacture the "Swarm" subwoofer system for home audio and home theater, which consists of four small subs intended to be distributed asymmetrically around the room. Each generates a different room-interaction peak-and-dip pattern, and the four dissimilar peak-and-dip patterns sum to much smoother in-room bass than any one sub alone. And "smooth bass" = "fast bass", because the peaks literally take longer to fade into inaudibility, so they tend to stick out like sore thumbs. The advantage of this approach over EQing a single subwoofer is that the improved smoothness holds up throughout the room, while using EQ to smooth the bass for one location results in WORSE frequency response elsewhere in the room because the peaks and dips will be at different frequencies in different locations. A distributed multi-sub system is actually using "destructive interference" to bring down those peaks, so that they no longer stick out like sore thumbs.

    This is all because home audio and home theater rooms have dimensions which are small relative to the bass wavelengths involved, which results in relatively large, few, and far-between peaks-and-dips from any one bass source. Four bass sources in dissimilar locations = LOTS of smaller in-room peaks and dips, which is like what we'd get in a big room!

    So in prosound, we are dealing with BIG rooms, in that the room dimensions are LARGE relative to the bass wavelengths involved, so the modal density is greater and therefore we get more uniform bass energy throughout the room (though non-uniform distribution of the mids and highs can make it seem otherwise.) In a venue, the main bass region issue is, getting adequate sound pressure level! So we want to minimize "destructive interference" - it is NOT our friend in prosound! This implies clustering the bass sources as close together as we can so that their low frequency energy adds in-phase for all bass wavelengths for all listeners.

    PA systems usually have two speakers (or two arrays) for the mids and highs, spaced and aimed to give adequate coverage for the audience, which may not be the best way to present the bass energy to the room. So what you might try with two cabs is a "splayed array", cabs side-by-side (or even stacked), each aimed off to the side a bit to widen the area covered by the mids and highs.

    That being said, I am NOT a bass player, NOR have I ever set up a serious sound reinforcement system for a gig, so take the advice of a real professional in this area over mine.

    The "bass crawl" is indeed a good way of finding the best position for a subwoofer, and with multiple subs, what you would do is place the first sub like you described then set the second sub in the seating position and repeat the "bass crawl" with that first sub also playing. And so forth. Fortunately there are much simpler ways to position four subs well, and the location of no one sub is "critical" to the net results.

    Intuition would tell you that the more subs you have the more problems you have, but actually such is not the case. What you end up with is more peaks and more dips, and they are smaller and closer together. Smaller = less audible, and closer together = the ear's averaging mechanism (effective over a roughly one-third-octave-wide "critical band") can come into play and can result in perceptual smoothing greater than eyeballing the frequency response curve would predict. On the other hand, one big ubersub = deepest loudest bass for the dollar, and in that situation doing the "subwoofer crawl" is imo your best bet for optimal positioning.

    Here is a review of a distributed mult-sub sytem. Disclaimer - it happens to be mine, but to the best of my knowledge nobody else makes a dedicated multi-sub package system, so nobody else's has been reviewed. The general principles are essentially universal, and most people who use a distributed multi-sub system create their own by simply buying a bunch of subs. They can even be dissimilar.
     
    Last edited: Oct 13, 2021 at 10:48 PM
  18. monkeyfinger

    monkeyfinger Moderator Staff Member

  19. 0FE5BF2B-7A37-4EB3-A45F-9FA839B89C70.jpeg

    Ace Frehley band at sound check. I was doing the same thing back in the 80’s when I carried around two 8x10’s. What it comes down to is this and nothing else… do the guys on that side of the stage want it?
     
  20. RColie

    RColie Gold Supporting Member

    Nov 21, 2007
    Eugene, OR
    An anecdotal story...I was at an outdoor jazz concert years ago (Rippingtons, Yellow Jackets, others). I was sitting in the grass about 100 feet from the stage. The subs were underneath the mains on each side of the stage. As I walked across the grass parallel to the stage, the bass suddenly dropped out, so much so that I thought the PA had a malfunction. As I kept walking the bass came booming back in. It looks to me like I experienced what the graphs posted by @Wasnex illustrate.
     
    Wasnex likes this.
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Oct 17, 2021

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