Audio Broadcast for Graduation Event

[urban79]

So I received word that we are looking at a "drive-through" graduation event this year. One of the first questions that came up was about distributing audio to all of the different cars. My first thought/hope is that we can get a local radio station to broadcast the ceremony for us. Barring that, my next thought is we live stream and have people have the audio play on their own devices in their cars, but this introduces lag since we plan on having a local sound system as well. I could also try just making the sound level high enough at the stage to cover the track, but I feel like that could be challenging.

Am I missing any obvious solutions? I assume anything in the way of an FM modulator powerful enough to cover such an areas must be illegal...

Chris

 

[StradivariusBone]

You can buy FM transmitters online. I have no clue about the legality of it, but I know that a few people near me have used these for their Christmas light displays when they set them up to run with an audio track. I'm curious, what is your plan with this? Like a drive in movie kinda deal where cars park facing the stage? Our schools are desperately trying to figure this out for our seniors as well. Right now anythings on the table.

 

[StradivariusBone]

You know I had another thought. I rarely listen to my FM radio in my car anymore in lieu of music via my phone. It would not be hard at all to setup an audio stream that could be accessible via any of the big streaming platforms and do it that way. And you could probably accomplish it with gear you have on hand.

 

[Calc]

You know I had another thought. I rarely listen to my FM radio in my car anymore in lieu of music via my phone. It would not be hard at all to setup an audio stream that could be accessible via any of the big streaming platforms and do it that way. And you could probably accomplish it with gear you have on hand.

Yes, but it would have significant lag if using any of the cloud providers. Around 30 seconds or so which doesn't sound too bad, but significantly behind any live event.
Chris, what's the justification behind the local sound system? If everyone's in their cars and you can come up with a good solution for that, I'd stick with just that.

FM is ideal here, but I have no idea how practical that is. Anything streaming-based will be easier to set up, but you run in to congestion issues since everyone needs their own separate connection. That'll come down to the size of your crowd and the cell coverage in your area- if the cell towers don't usually see that much traffic in that area, they likely aren't equipped for it, and the stream will work great in testing and fail spectacularly at the event.

 

[TimMc]

The short answer is "anything that transmits in the FM broadcast band must be licensed;" in the USA there is no provision for Part 15 use of that spectrum. There is a company in Canada that makes a low power FM exciter, up to 1.9W, from 87.9mHz to 108.1. Buy their antenna and RG-8 cable. Will easily cover a parking lot, get the antenna up as high as you can. Don't ask me how I know...

 

[NickVon]

30 second lag doesn't matter as no one who will be seeing it "live" (if anyone even is) will be streaming it to. 30 second lag is fine when it's the only way people are interacting with the event.

 

[StradivariusBone]

Yeah and 30 seconds is on the upper end of lag for the streaming I've seen. YouTube can get it within 7 or so seconds. If you pare it down to just audio that might speed it up too. I'm just thinking of what you could do with the gear you might already have. Anything related to this sort of thing is starting to or already scarce. It's almost impossible to pick up even a webcam at MSRP right now. You can't guarantee the bandwidth would be available at showtime though. That many phones downloading at once would certainly strain the network.

 

[TimMc]

Or your own wireless network, local server (ShoutCast?) perhaps?

Eh... I went back and looked at Shoutcast (been a long time) and now see it's evolved a lot from when I was first looking at it. May not be the answer I hoped it was.

 

[Ben Stiegler]

check out Williams Sound - they are hearing assist leaders, and recently introduced solns for drive-up parking lot worship and assemblies. - https://www.williamssound.com/catalog/fm-w20

 

[FMEng]

Keep in mind that the Williams product does not broadcast to car radios. The "FM" part of it is referring to hearing assistance receivers. Their product would provide a lower latency method of streaming than by using a cloud server. The latency isn't zero, but it would be much better than typical streaming. It does have a connection limit of about 200 though.

 

[urban79]

You can buy FM transmitters online. I have no clue about the legality of it, but I know that a few people near me have used these for their Christmas light displays when they set them up to run with an audio track. I'm curious, what is your plan with this? Like a drive in movie kinda deal where cars park facing the stage? Our schools are desperately trying to figure this out for our seniors as well. Right now anythings on the table.

So my initial thought was a drive-in movie setup, and I apparently did not have the winning idea. The setup is our local fairgrounds, and they plan on having cars circle the track, have the graduate get out at the stage, "walk", take pictures, and then get back in their car.

Yes, but it would have significant lag if using any of the cloud providers. Around 30 seconds or so which doesn't sound too bad, but significantly behind any live event.
Chris, what's the justification behind the local sound system? If everyone's in their cars and you can come up with a good solution for that, I'd stick with just that.

FM is ideal here, but I have no idea how practical that is. Anything streaming-based will be easier to set up, but you run in to congestion issues since everyone needs their own separate connection. That'll come down to the size of your crowd and the cell coverage in your area- if the cell towers don't usually see that much traffic in that area, they likely aren't equipped for it, and the stream will work great in testing and fail spectacularly at the event.

My reasoning behind the local system is the fact that the family will be at the stage for photos and so it seems weird to not have local reinforcement - I may end up rethinking that, but there would still be some noticeable delay as you get closer to the stage - granted, much less if it's not being amplified. Our best bet this way is to have the local radio station set it up for us - hoping administration can pull that one off. They also want a picture slideshow and potentially prerecorded speakers, so I'm trying to figure out where I can rent equipment from for that end of this too, since nothing we have in stock will compete with sunlight midday. It will have to be livestreamed as well, but I hate to put all my eggs into one basket when there is a local component...

 

[TimMc]

Your slide show will require an outdoor-rated LED wall. What image size and how much electrical service is available?

I'm kind of liking the holiday display lights transmitter... or several of them. Local sound at the stage can be speakers on sticks. A cleverly edited video could make this look like a 'normal' graduation, except for the lack of crowd noise.

 

[RonaldBeal]

The short answer is "anything that transmits in the FM broadcast band must be licensed;" in the USA there is no provision for Part 15 use of that spectrum. ...

Incorrect. See the Fcc's input here : https://www.fcc.gov/media/radio/low-power-radio-general-information
Legal part 15 compliant FM or AM transmitters are low power, and generally limited to about 200 feet range... That's why bluetooth to fm adapters for cars are legal, and how many of the christmas light transmitters work.

 

[TimMc]

Thanks for correcting my error, Ron!

 

[FMEng]

Incorrect. See the Fcc's input here : https://www.fcc.gov/media/radio/low-power-radio-general-information
Legal part 15 compliant FM or AM transmitters are low power, and generally limited to about 200 feet range... That's why bluetooth to fm adapters for cars are legal, and how many of the christmas light transmitters work.

If a Part 15 transmitter were placed up high, without obstructions, I would expect the coverage to be, at minimum, 100 feet in each direction. Car radios are quite sensitive and selective, so coverage for much farther is possible. I wouldn't be surprised if one could cover a football field with usable signal. Finding quiet channels will be critical. Avoid first and second adjacents to occupied channels.

If you use more than one, to enhance coverage, put them on different frequencies, so that they don't interfere with each other.

 

[Ben Stiegler]

So my initial thought was a drive-in movie setup, and I apparently did not have the winning idea. The setup is our local fairgrounds, and they plan on having cars circle the track, have the graduate get out at the stage, "walk", take pictures, and then get back in their car.



My reasoning behind the local system is the fact that the family will be at the stage for photos and so it seems weird to not have local reinforcement - I may end up rethinking that, but there would still be some noticeable delay as you get closer to the stage - granted, much less if it's not being amplified. Our best bet this way is to have the local radio station set it up for us - hoping administration can pull that one off. They also want a picture slideshow and potentially prerecorded speakers, so I'm trying to figure out where I can rent equipment from for that end of this too, since nothing we have in stock will compete with sunlight midday. It will have to be livestreamed as well, but I hate to put all my eggs into one basket when there is a local component...

I've rented video pop up trucks which have built in quiet generator, a nifty flip open roof, and a hydraulic lift which raises the video wall above the truck to a respectable height. Here in SF, I think it cost around $12k for a full day in 2016. It was fine at noon in full daylight. Depending on where you are, travel time might also impact the budget. Good luck!

this is not the vendor we used, but first that cameup on Google.https://insaneimpact.com/led-screen-rental/

 

[Calc]

Hmm. Bouncing ideas off-the-wall, (if you can't get the Radio Station to work):
With your speakers already pre-recorded, would it make sense to pre-package the whole event, and just 'perform' it live? Then your pre-recorded feed IS your live feed, whatever delivery system you end up using. You'd have to leave plenty of room for each graduate to make sure you don't fall behind, though.

Now, I've worked 2 or 3 commencements per year at my current job for the past seven years, so I don't say the following lightly:
Cancel family pictures at the stage.
Get a local photographer to come out, and shoot pictures for everyone. Everybody gets a free copy, but the photographer gets to upsell them more (this'll keep the school's cost down).
Even if the family still comes to the stage to cheer, them taking pictures is going to double the time it takes. Simplify/streamline as much as you can.

 

[urban79]

I entirely expect that the video is going to be too expensive - my only saving grace is the fact that there isn't much else that can happen right now, so maybe I might get a deal on equipment literally gathering dust.

We have done the official photographs in the past - I *hope* they intend to do the same this year, but the reality is family's are going to take pictures too - they always do. The idea of a couple of fm modulators mounted high up is interesting though - I might have to try that out. Thankfully we have two months; unfortunately we are far, far upstate New York - basically in Canada.

 

[Ben Stiegler]

I entirely expect that the video is going to be too expensive - my only saving grace is the fact that there isn't much else that can happen right now, so maybe I might get a deal on equipment literally gathering dust.

We have done the official photographs in the past - I *hope* they intend to do the same this year, but the reality is family's are going to take pictures too - they always do. The idea of a couple of fm modulators mounted high up is interesting though - I might have to try that out. Thankfully we have two months; unfortunately we are far, far upstate New York - basically in Canada.

which means the chances of getting detected using FM, or really causing any reportable problems is vanishingly small.

 

[Ben Stiegler]

here are 2 more crazy-ass ideas for you:

- if graduation was at night, you could do image magnification (imag) much easier - with a projector(s). What are the brightest projectors you've got on campus that aren't a total pain to get de-mounted/re-mounted? If you have a pair, you can double-stack them (aimed at same screen area, doubles the lumens). If you have (or can rent) 4, then using a simple video wall scaler can break it out to 4x the size. Probably way cheaper than hauling a video truck to the middle of the woods. (What's your school?)

Or - any active or abandoned drive-in movie theaters somewhere in the area? The screen's already there, maybe the projection and the car audio, too. Even if you rented out a drive-in for the nite, it might be convenient and plug-n-play ready to go. (Like Midway Drive-in in Minetto, maybe?) if you are in Syracuse as I'm guessing.

Let us know how this evolves - I'm fascinated!