On Stage – 2 cabs spread

Discussion in 'Miscellaneous [DB]' started by TwentyHz, Sep 25, 2017.

  1. Hi All –

    Next gig is in two weeks and I hope to try something like this on an outdoor stage at a fest. Anything you think I’m missing that could lead to problems/heartburn for the sound guy, e.g. bleed through into drum mics? Thanks!

    I’m newly starting to play the db out with some frequency. As I start to experience small indoor and outdoor stages, I’m trying to develop reliable autonomy in being able to hear myself via my little traveling rig as monitor. (Warwick LWA 1000 -> two 2 Eden EX112s).

    Sunday at practice I tried spreading my cabs, similarly to below, and raising them (both) up off the floor to waist height (usually I stack them). ‘Ta-Da’. I could really fine tune what I heard by moving further into and out of the field, rotating, etc. A few inches could make a big difference. I was surprised that taking one step could find me hearing speaker 1 mostly, speaker 2 mostly, both, (or with a step back, much less of either). The cab that was further seemed really valuable (perhaps due to that wavelength phenom people discuss or some room dynamics). My ‘mates could me hear me with no ill-effect, and they reported a nice rich saturated omni/non-directional experience.

    Am I missing something? Thanks.

    2cabs spread w.png
    Am I missing something?

  2. james condino

    james condino Spruce dork Supporting Member Commercial User

    Sep 30, 2007
    asheville, nc
    I think your diagram is upside down. Put the drums and bass out front and the guitar player in the back!
    agedhorse and TwentyHz like this.
  3. Hah! But getting to hide in the back is one o' my favorite things!
  4. Tom Lane

    Tom Lane Gold Supporting Member

    I think sound reinforcement folks would probably recommend placing your two cabs in the same plane, so that you could draw a straight line from one speaker grill to the other. That's to minimize the amount of destructive interference in your sound waves. Next, put them further behind your band. You might try placing both speakers at the bottom of your drawing, one on your right and the other between your drummer and yourself. If you're using a mic, then two speakers seems more likely to create feedback, in which case I think I'd leave the speaker between you and the drummer but maybe move it just a bit behind the drummer while you move yourself back further toward the bottom of the drawing, and set a small monitor at shoulder height over your right shoulder.

  5. Thanks, Tom. very helpful. So far, I'm going straight pickup when playing out... if I get bold maybe I'll add trying just a smidge.

    2cabs 3.png
  6. Tom Lane

    Tom Lane Gold Supporting Member

    So that's about right. The speaker between you and the drummer might be a bit out of his ear shot so you could consider moving both back a bit further, or angling the plane between the speakers to point more at your drummer.

    I'm not a professional sound reinforcement tech but I worked as one for a couple of years many years ago. Maybe someone with better education will chime in.
    TwentyHz likes this.
  7. Thanks... I used this advice on the last couple of gigs and it helped... My quick temporary solution was to do a quick mod on a twin-conga stand to hold one of my little Edens at around belly height, angled up.
  8. I would stand on the other side of the drums, more forward so the fiddle slightly to the band as well as the audience and loose a cab.
  9. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Paging @agedhorse ......

    (That guy is stinking handy to have around, I tell ya....)

    He did/does theater sound and has designed bass amps/cabs for some of the best in the business..... currently Mesa. He should be able to shed some light on this....in his sleep.....with one hand tied behind his back. :D
  10. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator Gold Supporting Member

    Oct 19, 2000
    Louisville, KY
    I've never had any luck spreading cabs out like this. They always sound better stacked ( much to my chagrin).
  11. The reason that stacked enclosures give you more punch, all other things being equal, is because a stack of speakers couple to help produce a long sound wave.

    The fundamental of your open E string is a sine wave 32 feet long. You’re not going to project a 32 foot long sine wave out of two separate Eden 12s in tiny boxes placed 10 feet apart and set off axis at waist height.

    Look at the Dead’s Wall of Sound. The speakers were stacked in narrow columns to an enormous height. Ron Wickersham knew what he was doing.
    Jason Hollar likes this.
  12. Tom Lane

    Tom Lane Gold Supporting Member

    Can you explain the acoustical physics behind that idea? That's not what I was taught in audio engineering school but things change.
  13. That’s what I learned, theory and experience.

    There are different schools of thought. I dunno.
  14. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    Well, I've been called stinking at times and handy at times, but rarely in the same sentence ;)

    Often it doesn't work out all that well because of the combination of constructive/destructive interference between the two cabinets (if the distance is sufficiently large), and the additional reflective interference between the cabinets and the acoustic boundaries (stage floor, ceiling and walls). It can work ok, but not something a betting man would put much money on.

    The wavelength doesn't (and CAN'T) change with speaker configuration. The wavelength is absolutely related to frequency.

    A 32' wavelength can most certainly be reproduced by a pair of 12" speakers no matter where they are replaced. At what amplitude may be a challenge, and being spaced 10' apart will create some comb filtering with constructive/destructive interference resulting in peaks and dips in the frequency response at all filters based on the combination of frequency, spacing of the two speakers, and any boundary conditions.

    The Wall of Sound is a very special case, one I am very familiar with given my location and the people I have had the opportunity to work with. The columns were long for 3 separate reasons, the first was to intentionally use the inter-driver spacing to reduce the vertical dispersion while maintaining the horizontal pattern (basic line array theory), the lower the frequency the longer the length of the array required to maintain pattern control. The second reason was to decrease the energy density on stage while increasing the energy density projected into the audience. The principle behind this is based on cylindrical section analysis, and ironically is the same as what the little Bose line array sticks are based on. The third reason is purely practical. In order to transfer that many electrical watts into enough acoustic watts to achieve the necessary SPL in the audience with low powered speakers (yes, the speakers of the day were good for maybe 75-100 watts each) required a lot of speakers. This was fortunately a practical way to stack and rig for a more coherent sound. It was also a distributed mix (or initially intended to be), each columnar array contained a mix element and in most cases there were stereo element columns. There were a lot of other things that were not obvious, including additional mics on vocals that were necessary so that some off axis out of phase information could be mixed into the primary mic's mix to reduce bleed and the potential for feedback.

    In the end, it turned out to be more trouble than it was worth... but like many failed experiments, lots of really good principles were learned and developed that led to products by Meyer, Alembic, Gamble/Crest, JBL, Apogee, Harbinger, Furman, Ultrasound, McCune, etc.

    See above. It was a special case that didn't really work in a practical way, but led to many things we take for granted today. I was lucky to be working in the (pro audio) business (and in the region) not too long after the wall of sound experiment. I worked quite a bit over the years with David Grisman, John (Marmaduke) Dawson, Bruce Hornsby, Phil Lesh and Bob Weir in their various offshoot projects. Some of my favorite shows to mix were New Riders of the Purple Sage with John Dawson and various guest artists. Sadly John passed away a few years back from cancer.
    Tom Lane likes this.
  15. That’s what I said. I’m sorry your friend died.
  16. Wowzers; so looove reading the kinda stuff on the ol' TB. And bless us all - didn't we move lickety split from my 2 lil' Eden 112s to Phil & the boys' Wall o' Sound! Wait 'til I tell the fellas.

    Just to complete my newbie reporting for the sake of future readers... On the outdoor stage, I used a set-up like the pic below, where one cab sat on the stage and served as the drummer's extra monitor, and 1 cab was on the conga stand angled up towards me. All 3 of us could here me well, no mic bleed thru, no feedback etc. Audience probably didn't hear my cabs at all over the FOH, and sound guy wasn't getting them in the mics, so I guess the interference/plane issues weren't a factor for that stage at those levels.

    Tipped Cab.PNG

    Sunday, on a tiny indoor stage in a shotgun coffee house, with PA for vocals only, I stacked them as below. Success, again, aided I think by the fact that I was getting a lot of stage coupling /could really feel it up thru my feet. Very immersive and helpful for timing etc.

    Goat Cab.PNG
  17. Primary

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    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.

    Sep 24, 2021

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