Workflow for removing HISS

ihatedv

ihatedv

Well-known member
I am on CS4 with Audition and Soundbooth. Later I might have access to ProTools.

The hiss is from noisy pre's on my DVX.
 
You can try a notch filter at 10kHz to start, and then play with the center freq from there. It's not the best, but can reduce some hiss (not all) in a pinch. If you don't have a notch filter, make one with a parametric EQ by taking the bandwidth on a single filter (bell curve) down as small as it will go, then use center freq and cut to play around and find the sweet spot. But generally, it takes a specialty plug-in.

Depending on the hiss, SoundSoap LE is fairly good at noise removal. The full app, of course, is much better with more finite control.

I don't know what plug-ins Audition and Soundbooth come with, but generally the factory-provided noise removal with programs like that is less than impressive. You'd need to get something like SoundSoap, or Waves Restoration... both fairly pricey.
 
If it's much like tape hiss then it shouldn't be too hard to reduce. You can try the brick wall method of using a LOWPASS filter and just slide it down till the hiss is gone or till you start hearing it affect the dialog whichever comes first. If you have a lot of bright voices that can be problematic. A cheap BOX choice that works great on hiss is the Behringer (I know but even Skywalker was using this box) Denoiser SNR-202 (or similar). It is a frequency content sensitive expander. ie It lowers the high frequencies when there isn't much happening up there, like just hiss, and brings them back up if there is a bunch of content, like voices. You can probably get one close to free used.

As for plugins. Sound Soap (the cheap version ~$100) does pretty well on hiss. iZotopes RX can do amazing things (but at 3X the price) and then you can go to WAVES (at 10X the price) and it gets REALLY expensive after that.
 
I have found audition and soundbooth to have pretty good noise removal especially for hiss. If I remember correctly you can sample a section of the audio where the only the hiss is present then remove it from the whole file.
 
Tobia said:
I have found audition and soundbooth to have pretty good noise removal especially for hiss. If I remember correctly you can sample a section of the audio where the only the hiss is present then remove it from the whole file.
Click to expand...

AU and SB will remove hiss, but the downside is it leaves dialog very electronic sounding
 
maybe you were overdoing it with AU. i have sound forge with sony vegas and it works ok...
 
NR works best with a number of sallow passes. The better the NR the more (generally) that can be removed in a single pass with out the artifacts (electronicy, underwater sounding) being noticeable. RX can often remove 10 - 12 dB in a pass with out being noticeable, Sound Soap (when it works) is more like 5 - 6 dB. With each pass resample the "noise" so your always targeting the problem feq's.
 
Maybe work on getting your input signal hotter, and turning down your audio levels. Chances are your levels are turned up so much you are adding noise. If there is a "trim" control on the camera, or in the menu, try turning that up, and your levels down. It won't help with what's already recorded, but will in the future. Removing hiss in post will become a major drag.

Also - turn AGC off.
 
ihatedv said:
What is RX? Medicine? lol
Click to expand...

I think that IS the joke. It is an application by iZotope called Rx, and is the best bang for the buck noise reduction application/ plugin around (at least for the Mac (there was something called Diamond Cut for the PC that was pretty amazing if it's still around).
 
Noiz2 said:
I think that IS the joke. It is an application by iZotope called Rx, and is the best bang for the buck noise reduction application/ plugin around (at least for the Mac (there was something called Diamond Cut for the PC that was pretty amazing if it's still around).
Click to expand...

ok gotcha...
 
RX work

RX work

Today I used RX to fix some complicated recording... the shot consist on a actress talkig to camera while a bunch of women pass by running with heels on a tile floor...(yeap.. very creative). Here´s the original take:

http://www.postmedia.com.ar/varios/Fer/Falabella_ins_original.wav

And here´s the result:

http://www.postmedia.com.ar/varios/Fer/Falabella_ins_after_RX.wav

I was really happy with the result, knowing that we´ve almost no time for fix&mix this tv ad.

So.. imagine what this tool will do with just hiss :laugh:
 
I think you were a bit too aggressive with your noise reduction. You have a lot of flanging type sound. The high pitched, almost musical artifacts left when you pull too much out. That sound is unnatural sounding, and if women with high heals were walking past in the video, it's better to leave that in than to replace it with artifacts.

If you must lower the noise, don't be as aggressive, and you will have a better final result.
 
Chadfish said:
I think you were a bit too aggressive with your noise reduction. You have a lot of flanging type sound. The high pitched, almost musical artifacts left when you pull too much out. That sound is unnatural sounding, and if women with high heals were walking past in the video, it's better to leave that in than to replace it with artifacts.

If you must lower the noise, don't be as aggressive, and you will have a better final result.
Click to expand...

I think that too. I was mixing with the client next to me, so he specifically asked for NO HEALS, I´d no other choice... of course that the final result sounds unnatural and I really don´t like that, but lowering the NR didn´t help and the client.. well, it´s the client. On the good side, most of the artifact are masked by the music.
 
C2V said:
You can try a notch filter at 10kHz to start, and then play with the center freq from there. It's not the best, but can reduce some hiss (not all) in a pinch. If you don't have a notch filter, make one with a parametric EQ by taking the bandwidth on a single filter (bell curve) down as small as it will go, then use center freq and cut to play around and find the sweet spot. But generally, it takes a specialty plug-in.

Depending on the hiss, SoundSoap LE is fairly good at noise removal. The full app, of course, is much better with more finite control.

I don't know what plug-ins Audition and Soundbooth come with, but generally the factory-provided noise removal with programs like that is less than impressive. You'd need to get something like SoundSoap, or Waves Restoration... both fairly pricey.
Click to expand...

ok in AU there are 6 freqs I can play with. How many should I set to 10khz's? Can you give me some other freqs to throw in there (
ex. 2 @ 10khz the other 4 @ ?khz's). the hiss im trying to remove is from the noisy pres on the dvx, i had to crank them up..

thx
 
You can select a section with just the preamp noise and use the Spectral Frequency Display tool in Audition, that will tell what frequency should look for. You´ll end up with a range of frequencies, just center your notch filter in the middle and tweek the Q parameter (less value - more open the notch will be). Always, if you can afford, use a spectral repair tool, because this things let you hear the "removed noise" instead the original audio.. that´s very useful because you can hear how much of your needed material are you removing.
 
Man, does anyone else ever feel like the audio section on these boards are like WAY more informative than any other section?

Big thanks to all you audio gurus who take the time to inspect, evaluate and share your opinions!!
 
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