Beaming in a 4x10 cabinet

Discussion in 'Live Sound [BG]' started by OldFartBassMan, Sep 29, 2017.

  1. OldFartBassMan


    Jun 10, 2004
    Central NJ
    Hey gents, got into a discussion with an "audiophile expert/bass player"' friend, and I'm trying to share my perceptions (which of course are more correct than his..)

    I was at an outdoor concert, where the bassist used a 4x10 cabinet. Great, punchy bass sound, even at a distance of 200 feet. BUT, it SEEMED when I walked off-axis, to the side, the bass power diminished considerably; returning back to on-axis, the bass came alive.

    I did NOT hear this with the next band, they used two 15s, (stacked vertically).

    Can anybody comment on whether a 4x10 rig would 'beam' it's output with so much directionality? My AE/BP buddy categorically claims this is impossible, I don't agree. WHAT SAY YOU?
  2. Geri O

    Geri O Endorsing Artist, Mike Lull Guitars and Basses Gold Supporting Member

    Sep 6, 2013
    Florence, MS
    First, the word "audiophile" is synonymous with the word "ignore"...

    When multiple drivers are placed close together (within a 1/2-wave, 1/4-wave, I've forgotten all the particulars), such the arrangement of the 410 cab as well as the line arrays used in modern concert sound reinforcement, the output of the drivers couples for more energy and increased directivity. This is why 410s are great on-axis, but seem to fall off as you get more off-axis. This phenomenon is used to accomplish certain goals in coverage and directivity in PA speakers.

    This is way over-simplified and hopefully, someone will come along with more details and particulars on how driver coupling works, both bad and good.
    walterw and BurningSkies like this.
  3. I'm not experiencing 4-10s any more or less beam-y that 1-15s or 2-15s either.

    In the field, I tend to push a 2-10 on top of a 1-15 though.....but that combo loses it somewhat less in the wings. I dunno.

    Open air seems to suck the life out of music anyway, especially the low freqs. I played a 400 acre open pasture... ok, maybe it was a wheat field, but you coukd really hear the lows for about a 15 degree triangle to both sides of dead-on in front on the bass combo i was pkaying.

    Funny enough, that same cone of bass (the COB) was where all the dancing was too.
  4. seamonkey


    Aug 6, 2004
    Where ears are most sensitive, right in the mid-range is where a 4x10 is worst.
    At lows, 120hz a 4x10 is fine.
    Most people hear the mids and their brains fill in the missing fundamental. When the mids comb and dip, it sounds like the lows dip also.
  5. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Really outside you have to have enough FOH to do the lifting for you, otherwise your stage volume is off the charts and getting a decent mix becomes near to impossible.
    walterw likes this.
  6. In my formative years I had no idea why I could be right next to a thundering 410 and have no clue what note I was playing from the sound getting to my ears.

    At the same time I would park myself dead in front of that same 410 and marvel at the tones of the resident bassist. One day I was on the other side of the room and there was only pillow bass.

    Still I had no idea why but I resumed the normal position thinking it was a necessity to be in front of a bass cab to get a proper bass blast because I like bass a lot and like a lot of bass.

    Then I learned some stuff about the physics of sound and all became clear. 410 810 610 all have poopiearse dispersion unless they are the .5 alignment fancypants kind.
  7. A 215 still beams but not nearly as badly as split 10's.
    BurningSkies likes this.
  8. Steve


    Aug 10, 2001
    what you are hearing is probably better though of as phase cancellation due to low end from multiple locations ( Cab plus subs on either side of the stage) hitting your ear unaligned.
    You should be able to hear that effect in most venues as you walk the room. Pretty darn annoying if you are tone or mix picky.
    bucephylus likes this.
  9. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002

    Interference calculations for typical 410 spacing will show that you get “comb” “beaming” for frequencies above 700 Hz, and really becoming important above 1kHz. Apparent “beaming” of the low frequencies is not the result of the side by side drivers. More likely to be issues with mains.
  10. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009

    out in the crowd you shouldn't be really hearing the stage cab that much anyway, that's supposed to be just for the player to hear themselves.
    DWBass likes this.
  11. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    the wider the speaker spread, the narrower the beam.

    in the most basic terms, the outside edges of a wider speaker setup start to cancel each other unless you're right in the center.
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