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Old October 7th, 2008, 02:47 PM   #1
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Interesting Sound Problem

I have attached a small clip that includes ambient audio of a person asking the presenter a question. Then the presenter provides an answer. I have clipped both ends short so there is just a little of each on the attached clip.

This audio was obtained via the method mentioned here. towards the end of the presentation, I was able to find the combination of Beachtek, house PA mixer, and in camera audio levels necessary to cut out the radio interference.

However, that was a minimal problem compared to the large roof mounted AC units humming away (off and on) through out the presentation.

I tried the Chorus tool.... honestly I did. But it just didn't seem to work right. I could never match the oscillations of the hum with the tool. I ended up just using the Track EQ to drop out all the low end and a high shelf to drop out the PA hiss.

I am posting my Soundforge cleaned up version for comment (as well as screen grabs of the spectrum analysis & the fx tool settings). Did I do a decent job eliminating the oscillating hum? Did I kill too much of the speakers tone? Was there too much of the hum left?

Alternate options? (ignoring everything mentioned in the referenced post about the connection problem). Post your version and see how it compares, I'd love to see (or hear) the differences.

You can find all the files I mentioned on my site.
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Old October 8th, 2008, 08:56 AM   #2
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jason,

gave a quick listen, I can't make out what she is saying in the question in either the unaltered or altered clip, there just isn't enough there. If you can make it out, I would suggest transcribing it and adding a subtitle graphic so the viewer knows what the question was.
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Old October 8th, 2008, 09:42 AM   #3
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reshoot filter.

Regards,

Ty Ford
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Old October 8th, 2008, 05:10 PM   #4
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Originally Posted by Bill Mecca View Post
jason,

gave a quick listen, I can't make out what she is saying in the question in either the unaltered or altered clip, there just isn't enough there. If you can make it out, I would suggest transcribing it and adding a subtitle graphic so the viewer knows what the question was.
My mistake. I was not indicating that the audience member's vocals should be changed. I was talking about the oscillating 60Hz buzz as well as other low frequency noise due to the air conditioner units in the gymnasium. The part before the presenter speaks was included just to give a baseline of the room.
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Old October 8th, 2008, 05:11 PM   #5
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Originally Posted by Ty Ford View Post
reshoot filter.

Regards,

Ty Ford
Ty, I'm not sure I understand what you mean by that? Other than re-shooting the event with a different mic (possibly skipping the house PC system entirely and opting instead for a direct to camera lapel system).

Is a "reshoot filter" a specific piece of equipment? Or is it an audio editing technique / software for post production?
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Old October 8th, 2008, 05:17 PM   #6
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I think what Ty was talking about is also called a "shoot-it-again filter."

In other words, you're hosed.

Martin
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Old October 8th, 2008, 06:30 PM   #7
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Originally Posted by Martin Catt View Post
I think what Ty was talking about is also called a "shoot-it-again filter."

In other words, you're hosed.

Martin
Heheh, yeah I was thinking that might be his best choice option. Unfortunately, us bottom feeder (ie charging bottom of the barrel prices just so we get clients.... aka using whatever other gear we have to make do) live event guys gotta make due.

I might look into asking facilities to shut off the AC units the next time they want to do one of these presentations (which should be spring semester). The AC units hang directly into the gymnasium so there is nothing to silence their noise.
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Old October 8th, 2008, 06:56 PM   #8
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About the only suggestion I can make is to close-mic 'em if you can't get the AC units shut off. If nothing else, scope out where the thermostat is and (possibly) move it up about ten degrees just before you start interviewing to get some quiet time. It's really rare that you can get a large facility to shut down the AC for you at less than gunpoint.

If you have to work with the AC going, like I said, mic them CLOSE to get intelligible vocals over the noise. Then, be sure to grab at least 60 seconds of the AC noise by itself. Why? Because if the AC shuts off during the talking, you'll need to be able to mix the AC sound BACK IN during your edit so the background sound will be consistent. People will tend to ignore a constant BG drone more than if the BG is part noisy, part quiet. I've done that with lawn mowers polluting the ambient. As long as the lawnmowers were there consistently from cut to cut, no one really noticed.

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Old October 8th, 2008, 10:54 PM   #9
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Originally Posted by Martin Catt View Post
About the only suggestion I can make is to close-mic 'em if you can't get the AC units shut off. If nothing else, scope out where the thermostat is and (possibly) move it up about ten degrees just before you start interviewing to get some quiet time. It's really rare that you can get a large facility to shut down the AC for you at less than gunpoint.

If you have to work with the AC going, like I said, mic them CLOSE to get intelligible vocals over the noise. Then, be sure to grab at least 60 seconds of the AC noise by itself. Why? Because if the AC shuts off during the talking, you'll need to be able to mix the AC sound BACK IN during your edit so the background sound will be consistent. People will tend to ignore a constant BG drone more than if the BG is part noisy, part quiet. I've done that with lawn mowers polluting the ambient. As long as the lawnmowers were there consistently from cut to cut, no one really noticed.

Martin

Ahhhh. I would not have thought to get ambient to mix back in.... but you are right. My attention was mostly draw when there was a change in the buzz, not that there was constant buzz (unless it was the times i was specifically paying attention).
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Old October 9th, 2008, 02:45 AM   #10
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Originally Posted by Jason Robinson View Post
Ty, I'm not sure I understand what you mean by that? Other than re-shooting the event with a different mic (possibly skipping the house PC system entirely and opting instead for a direct to camera lapel system).

Is a "reshoot filter" a specific piece of equipment? Or is it an audio editing technique / software for post production?
Hello Jason,

Sorry, that's what's we humorously suggest when the audio or video is too problematic and attempts to fix it while chivalrous, really don't improve things enough to make it worth the effort.

I do feel your pain. I'm guessing that you weren't listening to the audio while shooting, otherwise you'd have heard the problems. My suggestion for the future is to ALWAYS listen with Sony MDR 7506 or Audio Technica ATH-M50 headphones.

When I'm doing audio for a shoot and I start hearing stuff I don't like, I hand the phones to the producer, tell them what bothers me, and ask them if it's OK with them. This gives them the heads-up that there is a problem and lets them decide if it needs to be addressed. If they say it's OK, I'm fine with it and not responsible later.

Regards,

Ty Ford
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Old October 9th, 2008, 09:15 AM   #11
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Originally Posted by Ty Ford View Post
Hello Jason,

Sorry, that's what's we humorously suggest when the audio or video is too problematic and attempts to fix it while chivalrous, really don't improve things enough to make it worth the effort.
Actually I was listening, but I couldn't do anything about the audio. Budgets for this production was $300 total (and that all went to me to do the two camera shoot, render for online streaming & to burn 10 DVDs).

The kind of productions I'm involved in are much.... much lower end. :-)

But you do have one very good point in that I am using extremely low end headphones (which I always listen to while recording). I might not have been able to hear the slow oscillating sound at the shoot, bout I sure could hear the AC units..... there just wasn't anything I could do about them.

Yeah the efforts were more along the lines of chivalrous attempts. :-) Thanks for the reference on the headphones though.... I'll look into them because I have always been annoyed with low quality headphones.
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Old October 9th, 2008, 09:31 AM   #12
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Jason,

Again, I feel your pain. :)

I have, on several occasions, just said "no" to projects that I found would result in audio that would be glaringly below my own standards.

Small budget doesn't have to mean bad audio, but you have to draw the line somewhere.

I was on a shoot for a christian cable outlet from Texas. We were in DC atop the Commerce building. That's the one with the neat alignment of White House and Washington monument in the background. They have six shooting kiosks up on the roof for rent. (One is on permanent rent to the Japanese network NHK. They have an HD camera pointed at the White House 24/7, in case something untoward happens there...spooky)

Anyway, that day they were resurfacing the street betweeen us and the White House. BEEP BEEP BEEP, thunk, SCRAAAAPE, thunk, boom BEEP, BEEP, BEEP.

We tried shooting between the noise, but only had X amount of time. And so it goes.

Regards,

Ty Ford
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Old October 10th, 2008, 01:53 AM   #13
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And it's always the day that the binmen (trash collectors) come when I shoot!
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