8mm Forum: Audio options for small venue screening

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Posted by Doug Johnston (Member # 4747) on March 22, 2015, 04:14 PM:

I have offered to provide a small venue movie screening as part of a free City-sponsored event for local families and their children. In about two months, the City is offering a camp-out night for around 50 families in a historic park nestled in the center of the City. We'll also be welcoming kids from our local Boy's and Girl's club to attend as well - that's a big part of it for me!

The park features a historic steam engine train and a permanently placed train car that has a rustic wooden stage (10' x 10' beside the car). We are likely going to put a screen (probably a Da-Lite 100" Insta-Theater) on top of that stage. From there, we have a gentle upward sloping grade that extends about 80 feet back where the audience will bring their chairs. We're guessing about 100-150 people will be there.

My projector is an Elmo ST-1200 HD and the movie the City wants me to show is Pinocchio (a Derann full-feature length print I own).

Needless to say, I really want to do my best so that the kids in particular, have a memorable time.

I have the Elmo f1.0 lens which I intend to use which i think will be fine but, for audio, all I own right now it a pair of Elmo extension speakers. People far more experienced than me have said that I should consider using the ST-1200 auxiliary output (1/8" jack) to a stereo amplifier with a couple of half-decent speakers. Other have suggest a guitar amplifier combo or even an PA system.

Whichever one of those I were to go with, I have no experience withthem in this kind of an outdoor a venue. This will come out of my pocket. As such, even though this might not be a candidate film for stereo, I would want the solution to be one that could cater to stereo in case that situation arises in the future. One other thing of note that has always meant a lot to me is, I prefer vintage equipment. I used to play electric guitar 40 years ago, I've built Heathkit Amplifiers and Radio scanners too. So, I really appreciate the old stuff, probably a tube amp in this case.

Any suggestions that you might have would be very much appreciated.

Doug

Posted by Steve Klare (Member # 12) on March 22, 2015, 04:31 PM:

It sounds to me like your circumstances call for quick, simple and reliable: as few components and cables as possible and definitely monaural.

I'd definitely look into the guitar amp option: it's self contained and that will keep the haulage down and the odds of a bad connection too. If you search "guitar amp" in this forum, you can read about Janice Glesser doing exactly that.

I've had much better luck with the monaural aux of the ST-1200HD: the twin track outputs are so low in level that by the time you amplify them enough, you bring up a lot of noise too. The mono aux is higher in level and also controllable by the projector's volume control, so you can set it at the exact level the power amp needs. The twin track levels are fixed and usually need some kind of pre-amp to reach a usable level.

Ground loops are always possible in setups like these and bring all sorts of buzz and hum. The simplest way for you to avoid them is plug everything into the same outlet, like a multiple outlet strip. On the other hand if you plug the two cords into outlets 20 feet apart, you may be sorry.

I did a presentation in front of about fifty people with the internal speaker once and given the acoustics of the place it was plenty loud. You shouldn't need that much more. (Any speaker less than five feet across should do just fine!) [Wink]

Posted by Janice Glesser (Member # 2758) on March 22, 2015, 07:24 PM:

Here's my thread that Steve mentioned with photos of my amp speakers.

http://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=008105

Posted by Steve Klare (Member # 12) on March 22, 2015, 07:33 PM:

Nice, Janice!

When I saw that thread I thought "Now I want a guitar amp!"

-I already have a sound system, and I don't play the guitar either!

Posted by Doug Johnston (Member # 4747) on March 22, 2015, 10:18 PM:

Thank you very much Steve,

I very much appreciate your great advice and guidance to someone who wants to do it right but really has so much to learn.

I will go with the guitar amplifier as you suggested and will probably go with something very close to what Janice used in the post you provided a link to .

I'm putting a lot of pressure on myself to do this right. Murphy (my dog) and I are also Reserve Park Rangers (a K9 Unit) who have volunteered our services to the City for the past 7 years. We've been very lucky to have crossed paths with so many people in our lives and to hopefully, have made even a small positive difference, for some. I know the children who would be attending will be expecting a very special event from us.

You've really inspired me to follow your recommendations Steve.

Take care.

Murphy and Doug

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