Does anyone have any tips on how take an audio recording made of an NFL broadcast and render it unrecognizable, but still sound like a sporting event of some kind? I'm finishing post on a scene where two characters are talking in a bar while a television plays in the background and I don't want to draw the ire of the NFL. I want it to have sort of the sound of a game or something in the background but without individual voices being recognizable. I've already compressed it to within an inch of its life and lowered the volume way down, but you can still make out the voices.

I would just do a voiceover and make up team names. Then, blur the image.

Yeah, we considered that, but to pull it off convincingly would be almost impossible. Also, phony team names would be so cheesy. Things like that really destroy the illusion. Ideally the audio file would be distorted in such a way that you can just make out the peculiar cadence that NFL announcers have and crowd noise. You don't really see the television screen at all.

maybe you could use another sport, something less recognizable like a CFL game! (Canadian football league)

Isn't there stock audio you can buy for this sort of thing? Rather than asking how to infringe on NFL's copyright?

I know I've seen crowd noise SFX recordings somewhere. How about searching for crowd noise SFX, then mix it with someone announcing "generic" football action without mentioning team names?

This is off the top of my head, probably nuts. What would happen if you played the audio track backwards? Crowd noises are pretty much the same, I think; the voices would be disguised for sure, and if low enough, might pass. This is not the same as playing country music backwards, where the singer's wife comes home, the dog gets well and his truck gets fixed...:) /Battle Vaughan

Or, to refine Battle Vaughn's suggestion a little:
What if you duplicated the track, only reversed the sections that you didn't want to be distinct, and then layered them over the main track at a lower volume to muddle the speech, but not lose the "cadence" or feel of the original track?

And I heard that crack about "country music"....hahaha

Isn't there stock audio you can buy for this sort of thing? Rather than asking how to infringe on NFL's copyright?

As Chris points out, there are SFX libraries that have this type stuff.
A simple google search should help keep you from loosing your shirt to the NFL.

Try getting permission to record and use a local high school football broadcast. If you want to go all out, go to a game and record crowd noise, then get a copy of the announcer from the local radio station. I would think they'd be happy to help out. Just give them credit.

This is probably useless trivia, but I remember doing a project like this, must be 30 years ago when I was in college. I wanted some background vocals that were all fuzzed out but still a constant rhythmic presence, sort of like the constant fuzzy murmuring of the PA system in THX (the movie, not the sound effects company) 1138.

Anyway, I had this old analog FM radio tuner/receiver, and if you moved the tuning dial to just this much off of where it should have been, the sound fuzzed out completely. The cadence, rhythms and pitch were unmistakable as human commentary, but the words were totally indistinguishable, not much more than vff vff thf vff the hhff ...

There must be some sort of filter these days that does that. Ah, for the days before digital precision.

This isn't it, but I'm wondering what a google search for "vocorder" would turn up.

Adobe Soundbooth CS3 has a number of effects that would allow you to make the speech unintelligible, but still keep the cadence and "feel". Premiere also has several effects to do this.

You are gutsy and are skirting an issue that could have the NFL's lawyers all over you. I strongly would suggest you use some stock samples of what you need. Two sporting entities that you never would want to tangle with legally would be NASCAR and the NFL, they both defend their copyrights very vigorously and have endless resources to prosecute you and to locate your modified material if it is every broadcast or even on the web.

If you are modifying it to the point of non-recognition, what is the point of using their copyrighted material?

Dan