Funky Town Sound System

[Levi]

Hi everyone,

It has been long overdue that I have not posted our results from building our own sound system using Bill Fitzmaurice designs. Currently we are running 12x Tuba 60s in conjunction with 6x Omni Top 12s for our main sound system that only is present at Burning Man. We originally built this system in 2011 and added more to it in 2013 to what it is today. We constantly get amazing reviews from sound engineers to people just enjoying our parties that we throw throughout the week. The best recurring review I always receive is that our sound system is one of the cleanest sounding systems on the playa. Thanks to Bill for these amazing plans. 5/5 stars from Funky Town!

Levi

[Ryan Sober]

Why are you running your tops rotated 90 degrees? You're nuking your horizontal dispersion.

Also, the staggered layout of the tops is probably causing some phase cancellation oddities.

And, of course, the subs being split is causing some nulls in the listening area.

This is a beautiful setup. But it would sound better if it were set up properly.

[Bill Fitzmaurice]

it would sound better if it were set up properly.

+100.

[Tom Smit]

Nice system! It must thump pretty good!




Read the sticky.... http://billfitzmaurice.info/forum/viewt ... f=10&t=398

[Chris_Allen]

I know a lot of use would winge about the arrangement but in this context, aestectic is a huge part of the experience and from that perspective, this setup is very successful - looks great.

[Bill Fitzmaurice]

It may look great but having the tops like that is at the very top of the list of how not to place speakers, while having the subs as they are is a close #2.

[Grant Bunter]

Agreed, it looks great!

Agreed, it could sound better still with proper placement.

Levi,
When you all built the system, did you ever ask about the best way to deploy the cabs?
Do you understand what has been said about the nulls and cancellations due to the way the cabs have been set up?

If no, let me give you an example:
For T39's (whose HP is 40Hz with as many subs as you have), the minimum amount of separation if you split the subs is 56 feet. Otherwise you get frequency cancellation up to around 50Hz, due to the interaction of the 2 sets of cabs.

But you have T60's, HP 25Hz presumably.
Yet, the way you currently have them split/setup is still causing (ballpark) frequency cancellation to around say 50Hz.
What does that mean? You built T60's for nought.
You could have got the same result as you currently have by building T39's.

So, you have 2 choices to stop the frequency cancellations which are occurring;
Either separate the two stacks (a lot) more, or stack all the T60's together.

Sadly, aesthetics and the physics of sound rarely arrive at a reasonable result that works for both considerations...

[Boyd]

I'd look at doing something like this:

https://scontent-syd1-1.xx.fbcdn.net/v/ ... e=58834BA4

But stack the tops vertically on the outermost 2 high subs rather than fly them. This gets the tops working together as they were designed to - as a coherent line source, and the subs working together as they do best - as a single mono group. If you have enough amp channels, I'd consider powering the lowermost tops separately, so you can power shade them (turn them down a bit, as they'll be aiming at a closer audience), and if the width of the sub array causes the subs to drop off too much out to the sides (Dispersion is inversely proportional to the width of the array!), then deploy the subs in a staircase style arc (centre ones a little closer to the audience, outer cabs incrementally further back) to create a beam-forming array, which will widen the bass dispersion.

http://www.electrovoice.com/downloadfile.php?i=8913

This kinda stuff can make the difference between a system that sounds awesome, and, well, just another poorly set up system.

[Boyd]

(Dispersion is inversely proportional to the width of the array!)

Note that this applies all the more so to tops. As you've set up, the tops will only have about 10-20 deg coverage per box, The increased distance between sources, and the loss of line array behaviour will cause all kinds of unwanted inter-box interactions.

The preferred vertical j-array works together as a single line source, the horns couple together and act as a larger horn, the horizontal coverage is maintained, and the vertical coverage is controllable via the j-array vertical arc angles, to optimise vertical coverage, and SPL over distance.

A system that looks AND sounds good, is always better than a system that only looks good.

[Bill Fitzmaurice]

I'd look at doing something like this:
https://scontent-syd1-1.xx.fbcdn.net/v/ ... e=58834BA4

+1. That's the right way.

[Ryan Sober]

I'd look at doing something like this:

https://scontent-syd1-1.xx.fbcdn.net/v/ ... e=58834BA4

I love the fact that the subs and tops form a giant smily face... as if to say, yeah, we know this sounds incredible.

[Levi]

Wow, thank you everyone for the comments. This helps us out a ton since we only have one time a year when we can test the whole system together (long story).

I originally put the OmniTop-12s in a vertical arrangement, but after doing experiments with the arrangement I found that the horizontal arrangement, with angling, added a better mix on the dance floor. This was recommended by a tech from Funktion One that camped near us a couple years ago that recommended turning the Omni's on their side because of their height. , and after trying it I agreed. I'll try the other way again next year.

Stacking the subs was an esthetics move in the beginning, but we realized that raising the Omni's and angling them at 0, 30, and -30 degree angles really helped with filling dead spots on the dance floor.

@Grant Bunter
Thank you for the recommended in separation dimensions. I've been experimenting with separation over the years and this year I set the width at 48' which was a large improvement over 38'. There is definitely cancelation at about 100' from center, but then fills again around 110'.

Is there any way to stack the subs to keep these esthetics (guessing not)? The original plan was to put the subs under our DJ booth, but we built the booth for the T36s and not the T60 s so they will not fit.

Thanks again everyone!

[Bill Fitzmaurice]

This was recommended by a tech from Funktion One... recommended turning the Omni's on their side because of their height.

Funktion One doesn't make line arrays, so it's understandable that someone working for them would have no idea how a line array works. They're supposed to be high.
Required reading:
http://www.gtaust.com/filter/05/07.shtml
http://www.prosoundweb.com/article/in_s ... wer_alley/

[Levi]

Thank you Bill. I will take all the recommendations into consideration and make proper adjustments for next year Thanks!

[Grant Bunter]

@Grant Bunter
Thank you for the recommended in separation dimensions. I've been experimenting with separation over the years and this year I set the width at 48' which was a large improvement over 38'. There is definitely cancelation at about 100' from center, but then fills again around 110'.

Please note that the 56 feet separation I mentioned is for 40Hz and above and cancellations.

Obviously T60's go lower, so require even more separation.

The rule of thumb for separation is, split the cabs by at least two wavelengths at the required frequency.
So as a minimum;
40Hz = 56'/ nearly 19 yards
30Hz = 74'/ nearly 25 yards
25Hz = 90'/ 30 yards

That will most likely not be aesthetically appealing at all. So best to get back to the drawing board and work out an aesthetically appealing single stack, with sufficient split in the mains to allow stereo imaging...