View Full Version : FCP4: Removing hiss from audio


John Locke
January 14th, 2004, 12:50 AM
I have a back and forth dialogue between two people...one who had a booming voice, and one who speaks naturally in almost a breathy whisper. When recording, I had to jack up the volume a lot in order to even be able to hear the whisperer, but now the two don't match well because the background hiss is really noticeable on the whisperer's segments.

As I said, I'm not very good at audio...does anyone have any suggestions for minimizing this as much as possible. I'm sure I'll actually have to add hiss to the boomers clips to some degree, but I'd like to cut out the whisperer's hiss.

BTW...I posted this in the Mac/FCP forum because when an audio question is posted in the "Now Hear This" forum, I tend to get answers from people who really know their stuff but tend to use lots of jargon that I have no way of knowing how to apply to FCP and the filters it has available.

Ken Tanaka
January 14th, 2004, 01:25 AM
John,
Try the high pass (or is it the low pass?) filter in FCP. If the hiss is relatively constant you should be able to get good results after some experimentation. You may impact the actual voice a bit so you'll have to decide the degree to which you really need to attenuate the hiss.

Failing that, Bias' Sound Soap is a powerful tool for cleaning audio tracks. You will however, encounter the same decision, when using it.

Jeff Donald
January 14th, 2004, 08:07 AM
I use Sound Soap, and I've posted a link to a tutorial for removing hiss using Sound Soap in the past. I think I found the tutorial on the Sound Soap site, but I don't remember. Sound Soap has a filter specially for removing hiss, as I remember. Sorry for the vagueness, but I haven't had to use it in quite a while. It's not that I'm that good at audio (I'm not) just that I've made most of these mistakes before and I remember not to repeat them.

Christopher C. Murphy
January 14th, 2004, 08:11 AM
If you have access to a PC and want to use Adobe's Audition - that's the best I have used. I also have Soundsoap, but Audition actually is much better.

Audition used to be CoolEdit Pro, but Adobe bought them last year. I spent 8 months removing hiss, crackles and lots of other noise from 15 HOURS worth of music. In my opinion, the Waves plugins are ok...Soundsoap kinda stinks and Adobe Audition is the best.

Murph

Ken Tanaka
January 14th, 2004, 11:58 AM
Also, I noticed that Bias is preparing to introduce a new "Pro" version of Sound Soap that features an equalizer and other tweakies.

John Locke
January 14th, 2004, 11:59 AM
Aargh...I was hoping to avoid buying a new program. Never ends.

Ken Tanaka
January 14th, 2004, 12:39 PM
Hope springs eternal.

John Locke
January 14th, 2004, 08:57 PM
Jeff, I've got a looong way to go before I've made all the mistakes and can simply try not to repeat them.

You got me wondering, though...what would you have done in that situation? The mic was just barely out of camera view, and I'd begged and pleaded for the actress to speak a little louder...which worked...she went from inaudible to a faint whisper. The other guy...I put the mic as far away as possible and pleaded with him to lower the volume a bit...which he did, but his voice is just plain loud.

And taking into consideration the casting was already done, we had only a few hours to shoot, and I only had my AT815b mic...what could have been done differently to prevent the hiss on her segments?

Glenn Chan
January 14th, 2004, 09:29 PM
If this is a studio, turn up the volume on her headphones.

Give her ear plugs?! (same concept as above)

Ask her to project, like she's talking to someone at the end of the room?

---------------------
Removing hiss:
Use Bias Peak LE. Should be on your FCP disc.

Use the low pass filter to take out the high frequencies. Go overboard with the effect until you distort the voice, then back off. 6-8khz is about the top end of human voice.

After that you can try a noise reduction plug-in. Not sure if you have to buy this.

If you weren't battery powered and getting a ground loop, there's another trick for getting rid of even more noise.

You can apply compression (AKA graphic dynamics) to even out the man's voice a bit. You can also use a noise gate (AKA limiter/expander/graphic dynamics) to fade out the noise if it's low enough. If the noise is so bad that you can hear it when the woman is speaking, then you're in trouble (the noise gate will not work and the hiss is probably bad).

Glenn Chan
January 14th, 2004, 09:43 PM
Settings for filters:
compression: Peak should have graphic dynamics with curves. Basically you want to make it look like a hill that's very round on the top and mostly straight as you get down.

Noise reduction plug-in: sorry don't know the settings.

Low pass = certain settings on a graphic EQ. Low pass is self explanitory. Low frequencies are untouched and high frequencies are attenuated.

Noise-gate: Find the point where voice sounds wrong and then back off.

Use your ear and don't go overboard with the filters. Play it safe and don't apply too much of the effect. Listen carefully on good speakers/headphones and check the levels afterwards. Don't do the last part on headphones! You need to get close to whatever your target format is. Turn down the volume on your speakers and put them farther away to mimic the dynamic range of TV speakers in a noisy environment (normal listening situation).

You might still have to rubber band the volume (equivalent of the pen tool in FCP) or some other hack to even off the balance between the two actors.

Jeremiah Hall
January 18th, 2004, 04:30 PM
Take the actress' track, copy it, invert it, line it up perfectly with the original track, and put it on a seperate track, being careful not to copy/invert her dialogue (translation, just the parts that have no dialogue). If the hiss is consistent, you could try taking a small sample of it, invert it, and loop it. The two should cancel each other out, thereby eliminating your hiss.

Good luck.