Simple Noise Removal and Compress Dynamics Tutorial

Hi! I’m a huge fan of Audacity and have been using it to edit various radio and podcast projects for around a decade now, though admittedly I’m far from a power user.

A few months ago I wrote a simple (albeit long) post about noise removal and dynamics compression in Audacity and I’d love to hear where I may have gone wrong in some of my assumptions and overgeneralizations. The goal of the post was to get some fellow podcasters whose shows I really like into “listenable” territory while understanding that they don’t have a lot of time to devote to post-production aspects, so it approaches these topics from a beginner’s point of view.

The post is here: http://nototally.com/audacity-post-processing-tutorial-1-compressor-noise-removal/ and I appreciate any feedback that you impressive and knowledgeable human beings may be able to give.

The goal of the post was to get some fellow podcasters whose shows I really like into “listenable” territory

Do they think their podcasts are perfectly fine as they are?

There are broadcast shows that I can’t listen to for extended periods. No matter how much I complain about them, it never changes. It’s dreadful.

Koz

Usually, no. They’d like to sound better, but don’t have any idea how. I’m the rare podcaster with prior experience in audio production, albeit extremely minimal.

They’d like to sound better, but don’t have any idea how.

Get them to post. They do need to be using Audacity, but if they are, we do know how to shoot sound.

Fair warning, most of the serious problems with live sound recording can’t be cured in post production filtering and effects. One of the common AudioBook rejection notices happens when somebody shoots ratty and tries to “clean it up.”

ACX rejects the work as “Overprocessed.”

That’s just for AudioBooks and you can shoot a podcast however you wish, but there’s a standing joke about shooting sound:

I don’t need professional audio. I just need clear sound at good volume and no distortion or noise.

Koz

I’m coming back to this thread, so I’m a little scattered. Can you post work with no corrections?

Many times we can either suggest a correction process or tell you where you can put your microphone.

I did post a recipe for posting a simple sound clip for analysis:

http://www.kozco.com/tech/audacity/TestClip/Record_A_Clip.html

Koz

I like the publication, but it does suffer from off-board instructions and tutorials (such as mine). It’s out of date, seriously so in the case of Noise Removal which doesn’t exist any more in favor of Noise Reduction. Too many people were expecting Noise Removal to, you know, remove noise, which it rarely did. Oddly, Noise Reduction is much better at reducing noise sometimes close to zero than Noise Removal ever was. The reduction algorithm and the control panel changed.

They took the effect, burned it off, hosed it down and started over, successfully.

You also run into a problem I identified with my efforts to get people through ACX Compliance. Each post is different. Some are similar in a grand-overarching way, but the quality of the room, the quality of the voice and microphone problems are all over the map, so there is no “take this pill and everything will be better.”

You also can’t use a standard toolbox in the assumption that some performers will be paying attention and are spit and a penny away from announcing straight into ACX compliance with nearly no help at all.

“Oh, Cool. I made your voice very slightly denser with gentle compression [posted settings] and readjusted overall volume slightly to pass the ACX peak test [posted settings] and we’re out the door. How did you get your background so quiet? That kills most performers.”

There is one problem with your tutorial. It’s long. 12 screen scroll pages, and that’s only for Compression and Noise Removal. Nobody wants to be an audio engineer to do all this stuff and cranking through all those instructions is stiff. Particularly for the pick-up-a-cellphone-and-talk crowd.

I’m more than ever convinced you should record spoken works but leave the computer at home in the cupboard. A lot of our recovery and repair questions are about overcoming computer problems.

For standardized help, I will admit to using standard templates that I cut and paste into replies.

Audio Compressor
– Select the whole clip or show by clicking just above MUTE.
– Effect > Normalize: [X]Remove DC, [X]Normalize to -3.2 > OK
– Effect > Compressor: Thresh -20, Floor -50, Ratio 2:1, Attack 0.2, Release 1.0, > OK
– Effect > Normalize: [X]Remove DC, [X]Normalize to -3.2 > OK

I really got tired of writing that out each time.

Over weeks, I found that if you use that technique, which seems insane, adjusting compression is reduced to changing the Ratio number. You don’t change anything else. All the rest of the numbers in that list are the same pass after pass.

There are other tricks. Steve wrote a custom voice filter that eliminates rumble and low pitch sound problems. One swoop and many rumble noise problems vanish. Poop. Gone.

Etc.

But even with all that, sometimes getting someone to AudioBook heaven can take forum chapter after forum chapter.

The longest message thread on the forum is Ian who wanted to record audiobooks from his apartment in Hollywood. 39 forum chapters and over a year. It did work. He’s a published reader.

And all of this is assuming the performance can be fixed. Some can’t. Another copy and paste:

The Four Horsemen of Audio Recording (reliable, time-tested ways to kill your show)
– 1. Echoes and room reverberation (Don’t record the show in your mum’s kitchen.)
– 2. Overload and Clipping (Sound that’s recorded too loud is permanently trashed.)
– 3. Compression Damage (Never do production in MP3.)
– 4. Background Sound (Don’t leave the TV on in the next room.)

Koz