Beaming in a 4x10 cabinet

[OldFartBassMan]

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?

 

[Geri O]

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.

 

[SurferJoe46]

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.

 

[seamonkey]

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.

 

[4Mal]

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.

 

[Downunderwonder]

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.

 

[Downunderwonder]

A 215 still beams but not nearly as badly as split 10's.

 

[Steve]

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]

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.

+1

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.

 

[walterw]

Really outside you have to have enough FOH to do the lifting for you

this.

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.

 

[walterw]

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?

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.

 

[roadyboy]

I am just speculating , but wouldn't 4 10's stacked vertically have a wider dispersion as in a column array design. Hopefully, someone with actual professional experience will chime in.

 

[walterw]

I am just speculating , but wouldn't 4 10's stacked vertically have a wider dispersion as in a column array design.

yep

lots of folks do just that with a pair of 2x10 cabs stacked "tallways"

 

[Windreaper]

 

[Lobster11]

lots of folks do just that with a pair of 2x10 cabs stacked "tallways"

Yup. Just one of numerous reasons why I'd take a tall stack over a 4x10 box any day.

 

[Luckydog]

Someday try a Genzler array. I expect that my pair of BA210-3 cabs stacked (creating a 4-10) would likely beam similarly, if they didn't have the array drivers. But I can move anywhere on stage I want and hear pretty much the same volume/tone.