question on audio filters

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Best way to have have these noises is to not RECORD them in the first place.

In feature films (and much network TV), if the audio can’t be recorded cleanly under “live” conditions, it is REPLACED by re-recording the actors speaking the same lines in a quiet studio (ADR).

But, if you NEED to use location sound, you should have a professional audio operator mic it properly.
AND, let the audio pro have lots of input in your choice of locations, and whether or not a take is “good” based on the audio track as well as the video.

There are various noise reducing filters, Bias SoundSoap 2 (about $200) is one, that can help remove CONTINUOUS hum or buzz. It is less helpful if the noise in NON-continuous and/or at a frequency that is close to that of your dialog.

An audio Expander (filter or hardware) can help drop background noises to a somewhat lower level, but if not used precisely, can cause the audio to PUMP up and down in level and actually sound worse than before it was expanded.

[David Roth weiss]

Louis,

The noise reduction tools in Soundtrack Pro are pretty cool, easy to use, and they work well. Do the tutorials and you will learn very simple techniques that help you clean up your tracks up quite nicely. I’ve used the most expensive tools available in the past, and I’m amazed at just how good the tools in STP really work.

As Matte said, much of the location audio recorded for film and TV is replaced using ADR, often referred to as “looping.” However, there are many things that are done in post sweetening to improve audio using tools that you have already, or can easily add to your arsenal.

The most important thing to wrap your head around is compressing the voice tracks. This is very different from the type of compression we now think of, such as MPEG2 compression. Compressing the voice tracks squeezes them into specific frequency ranges that tend make dialogue sound clearer, as well giving perceived separation from the frequencies of music and sound effects so that voice doesn’t seem to compete against them. This is why a professional mix is able to deliver music and effects at relatively high levels, while dialogue and V.O. are still clear, crisp, and audible.

I have not yet used the various compression filters in FCP and STP, but I’m certain that you can get very good guidance about those specific tools on the STP forum.

DRW

[Louis]

Thank you very much for your responses, I really appreciate it. It really helps to know about looping now. I don’t think I’ll be able to do that though so I’m going to experiment with compression and filters. That makes perfect sense now that I think of compression (I know just a tiny bit from song recording). And it sounds like I need to get my hands on STP! I wish I was at school so I could try right now, lol, thats why I need a laptop!
Thanks again,
Louis

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COMPRESSION (which makes low-level sounds louder, and higher peaks lower) is is exactly the OPPOSITE of what you want with “noisy” tracks.

If the track is CLEAN, David’s suggestion of “tuned-EQ compression” is a good technique, but with background NOISE already present on the track, it can actually increase the problem.

EXPANSION is the effect you need to reduce background noise (somewhat). It makes “foreground” audio more pronounced, and drops “background” signals lower.

Simple versions of both of these filters are included in FCP, but it takes a very cautious application of either.

“Expander/Noise Gate” Audio Filter is the one to look for.

[Louis]

ooh ok. thanks for clearing that up! I’ll let you know how it goes once I get my project into FCP.
I really appreciate all of the help,
Louis