Quad set up

Been asked to supply 4 stacks all facing inwards tomorrow..550 people their idea is to keep overall noise down with lower levels close to everyone. So I assume no delays but what about anything else ..polarity? 

Edited by mattd - 25 May 2024 at 10:33pm

mattd wrote: Been asked to supply 4 stacks all facing inwards tomorrow..550 people their idea is to keep overall noise down with lower levels close to everyone. So I assume no delays but what about anything else ..polarity?  Any advise before tomorrow much appreciated. I'd still be keen know for next time anyways if tomorrow passes. Delay stacks wouldn't really work in here BTW Any ideas welcome :)

I guess he meens that you only have subs in the stacks closest to the stage, and no subs in the stacks away from the scene.

Edited by FOO - 26 May 2024 at 1:36pm

and don't try to make your dancefloor too big - there's a limit to how much variation in arrival time there can be before the your brain just hears a pair of trainers in a tumble dryer.

Not entirely on topic but one of the nicest sounding systems I've heard was many years ago at Glade festival, there was a Quad Opus system with four identical stacks of (if I remember correctly) 2x HB121 and 1xAT2000.

Conanski wrote: Keep everything in the same polarity, but if you are running in stereo switch the channels around on the back side... see diagram below, this gives you 4 distinct stereo zones around the dance floor. R  --  L L  --  R

The above method is what I used when I provided a small system for an open-air party in the garden of a friend's house in the countryside some time ago.

I got the 4 stereo zones and a bass "sweet spot" in the middle area of the dancefloor as expected, bearing in mind that "everything was in the same polarity".

The "dancefloor" was about an 6m x 6m square on the lawn. I used a bass bin with a pole mounted top box in each corner.

Once everything was set up and running at a good level, I thought I would take a walk around to see how far the sound was travelling, and if we were likely to get complaints.

I was really surprised how quickly the level of bass dropped off when outside of the dancefloor in all directions.

ie. The bass "sweet spot" on the dancefloor, caused by the bass bins running in phase but pointing in opposite directions, was one effect of the Quad set-up.

But another effect of the Quad set-up was a cancellation at bass frequencies related to the distance that the bass bins were apart, occuring outside of the dancefloor.

So the Quad set-up seems rather useful to me for small open air events.

I take the point "Snowflake" mentioned that this method will not work when the distances between the speakers get much bigger in order to cover a bigger crowd.

I note that the half wavelength of sound at 50 Hz is about 3.5m.

If somebody here feels like computer modelling what is happening here I would be interested in seeing some plots.

Edited by APC321 - 27 May 2024 at 3:12pm