Outdoor Surround Sound System

[maxmercy]

"V-load 4 subs in a row or stack them in two columns."

I believe both will work well, as described in the stacking and placing subs sticky:

http://billfitzmaurice.net/phpBB3/viewt ... ?f=1&t=398

Quote:
Here's the same treatment applied to Tubas.


With more than 2 cabs stack them above the first two.


Or go side by side:

With side by side clusters of Tubas the space between the mouths of the cab pairs is pretty wide, limiting how high a frequency the two cab pairs will couple to. T36s would have to be crossed over at 70 Hz, or less, T30s at 80 Hz or less and T24s 100 Hz or less.
EndQuote:

Not sure what the numbers are for the coupling of THTs when you go side by side, or what shape the coupling plate would best be for THT since it doesn't have the mouth flare of the Tubas or Titans, but I bet Bill knows offhand...looks like if you could stack them in two columns you could crossover higher to the tops...

JSS

[Bard2dbone]

I don't know if this is obvious, but just in case I'll post it.

I'm guessing the screen will be retractable in some way? Will it have a rigid frame on which the screen would be pulled up into place? Or would the whole frame somehow fold down as well when it's time to put the screen away? If you're mounting your screen on a trailer that has your subs and center permanently attached to it, you might consider setting up your cabs to go behind the plane of the screen. So perhaps the screen could be high enough that the cabs are visible underneath. Or maybe the screen could be lower for stability and the cabs would be behind it.

Back in the day, I played in a band that would improvise live soundtracks to silent movies. At first we wore all white and draped the stage in white and the movie was actually shown on us. We ended up having to turn our backs to the audience or close our eyes, because the whole gig was like staring into a spotlight. Then we got access to a big screen from an actual theater that had closed and we played behind the screen while watching the movie showing 'backwards' in front of us.

The point of that memory was that everything sounded just the same in the audience whether the screen was in front of our cabs or not.

[Bill Fitzmaurice]

The point of that memory was that everything sounded just the same in the audience whether the screen was in front of our cabs or not.

+1 for subs. Theatrical screens aren't solid, they're porous, to allow sound to pass through. But even porous screens hinder high frequencies, so behind screen theater speaker systems are EQ'd to compensate for that.

[TomG]

We are not 100 % sure about how we will mount the screen. Our current idea is to build a frame out of metal conduit. We would design it so that it could be dismantled and loaded onto the trailer for transportation. The frame would slide into metal sleeves which would be welded to the trailer frame. The screen would be stretched across the frame and pulled tight with bungee cords.

[djtecthreat]

This is such a great idea, I wish I could do something like this in our area.

[jcmbowman]

Aren't there legal implications for public performances of copyrighted movies? Or do you get some kind of blanket permission from the MPAA?

[Bard2dbone]

I think you can show a copyrighted movie in public. You just can't charge for it.

[gdougherty]

I think you can show a copyrighted movie in public. You just can't charge for it.

That is incorrect. If you read the legal notices included with your movies, public or private showings to large groups of people, for profit or not are prohibited. To show a movie to a larger group outside of a personal viewing requires the proper license. We've had to do this with churches showing movies to a congregation.

Found this online with a quick Google search

http://www.messiah.edu/offices/its/medi ... wchart.pdf

[Bard2dbone]

Harumph...

I was apparently told wrong.

[TomG]

Our Movies in the Park program is cosponsored by our local school district. This enables us to show movies under their lincense. Still there are certain movies that we are not permitted to show.

[jeffbabcock]

I don't want to rain on the surround sound parade, but keep in mind that if your seating area grows too large it will slowly become a sonic nightmare and a coverage challenge.

First, coverage. To do it right, each location in your "5.1" implementation needs to evenly cover the ENTIRE venue with sound from that channel at that location.

Secondly, latency. Consider what would happen in a 100ft wide venue. Sitting in the middle of the venue will be pretty good, but consider the person sitting all the way on the end row. There will be a HUGE difference in arrival times from the various speakers, and as the venue size increases it will go from having poor intelligibility to becoming extremely distracting at these outer ranges of the seating area. Surround sound becomes impractical due to latency if you get too big.

That's not to say you shouldn't try it. Keep the seating area fairly small and tight and you'll be OK, just be aware that the more it scales the worse it may become.

[djtecthreat]

As cool as Surround sound would be, I have to agree with Jeff and say that it will most likely be a crap shoot if its a decent span between speakers.

I was thinking this in the beginning of the thread, but didn't want to be the nay-sayer.


If it were me, I would focus on making the sound full with good volume over the coverage area, and really packing a punch in the low end which would definitely bring in that excitement to the listeners/watchers.

[maxmercy]

Pardon my ignorance, but how do movie theaters get away with surrounds (other than a high mounting position)? There are theaters in the 100 foot range dimension-wise...with seats wall-to-wall...although I will have to say, I am no fan of sitting near the side-walls....the surround speakers do intrude and are too noticeable. But yet there are people seated next to walls every time the theater is crowded...

Home theaters also suffer from this to some extent, if you are seated too close to a surround speaker, it can sometimes dominate your attention...but again, most people have no clue. They are just happy that something is coming out of the surround speakers they paid for, and hearing it can actually be a justification for the expense...

I think 5.1 (or now, 7.1) outdoors is do-able, as long as the surround loudspeakers are a decent and equal distance from the core audience (echoing Jeff), and as above the audience as is practical, as in a theater. The informed listeners will know where to sit...my guess is most people will be there for the social gathering, not a critical listening session...and the bass-freaks will be close to the screen directly in front of the THT cluster...

Also, with a 16'x9' screen, I'm not sure just how big the audience spread will be...

But I will have to definitely give credence to what Jeff and djtecthreat are saying. If you have a great LCR (or just stereo) setup, people may not even notice the surrounds are missing...but would you? I guess that is the real question...

JSS

[jcmbowman]

I'm going to have to disagree on the efficacy of surround sound outdoors. Most of the program being sent to the rear and side speakers in 5.1 and 7.1 setups is effect and not critical to comprehending the movie, but it makes the difference between watching a movie and being immersed in it. It's not critical that the surround speakers be properly balanced, nor is it critical that they be perfectly time-aligned. If you do setup outdoors in a big area with 5.1 or 7.1 there will definitely be a sweet spot, and the people truly interested in the movie will gravitate towards that area, but with the wide dispersion of the BFM boxes that sweet spot will be pretty large.

I'd say try setting it up for 5.1 or 7.1 in the venue at least once, and then do some A/B testing with and without and see if the difference is worth the effort of setting up those additional speakers.

[davygrvy]

I'd just like to mention something regarding surround speakers that wasn't mentioned before. The best way to make sure the side speakers do not intrude on those seated near them is by getting them up high and pointing them such that coverage is even. Time delay can't be dealt with, but our brains do a good job of interpreting that offset. Just make sure voice announcements are done on the center channel rather than panned center stereo. About then it makes a difference, but not by much especially for a non-reverberant space. I forget the album title, but Steely Dan has a surround album on SACD that would be killer for incidental music. If you can, don't use the LFE channel, but use a bass management one where the sub signal is the sum of the discretes. IMO, sounds best that way.

Outside in full surround with big subs is going to be wonderful. post some pix. San Rafael, CA used to do that right on main street (actually 4th street) right in the middle of town. The stores stayed open late.. It was a thing. Lots of fun.