Normalisation and compression with two separate voice tracks

If this has been discussed elsewhere, my apologies; I did a quick search, but I don’t know the relevant terminology yet.

I’ve started a podcast with a friend (you can find the first episode at - iTunes review pending). As you might expect, I’ve checked out tutorials and videos on how best to edit the audio and improve the sound; one thing I’m not entirely clear on, though, is how best to do all of this when I’ve got myself and my co-podcaster recorded separately.

Is it advisable to do some basic maintenance edits first on the two tracks (I’m thinking e.g. of ensuring that there’s no clipping) but then first edit the two tracks together, make the necessary snips and tweaks, mix the two tracks and then normalise, compress and equalise the resulting mixed track? Or do I do all of the steps with each of the individual tracks and then edit them together? Or is yet another procedure advisable?

Thanks in advance for your helpful tips!

By what method did you coordinate your show? Call each other on the phone, Skype? It’s not recommended to record the Skype call. You can do that if you absolutely have to, but it usually doesn’t come out very well.

how best to do all of this when I’ve got myself and my co-podcaster recorded separately.

It’s not a contest to see how many effects you can apply. The fewer the better. If your podcast takes off, you’ll need to remember to do your effects dance each time and that gets tired in a hurry. Separate tracks is very highly recommended because that’s the only way you can make the general quality of the two voices match. That’s a very big deal for pleasant listening.

After you mess with each individual track, you can Tracks > Mix and Render to a new Track. That will give you a separate mixed track which lets you apply corrections to both at once. MUTE and SOLO as needed.

When you get a show you like, Select that one corrected track by clicking just above MUTE. File > Exported Selected. It is recommended you Export a WAV (Microsoft) protection copy of the show before you produce the post. I assume MP3. You can’t re-edit an MP3 without compression damage and you can’t easily make a different compression copy. You can from the WAV. Keep the WAVs of the two original performances. If they’re MP3, stop that. Do all original production in WAV.

I need to listen to the sample to see how free-wheeling your presentation is.

Did you find that the two durations were different when you overlayed the two tracks? That’s normal. No two recorders ever come out perfect until you get into the Hollywood equipment. You can correct that with little or no damage with Effect > Change Speed. I think that’s the one that lets you simply type in the durations you want and it takes care of the rest. Once you do that the first time, it should stay constant from now on—until one of you changes recorders.

So how did you do the show?


Quick reply, which I hope will give you a better idea: we talk via Skype but each person records separately, using Audacity and saving the resulting sound file as a WAV.

The first episode suffers from audio glitches on my co-host’s side; we’ve already resolved this, but yeah, the first episode worse in terms of recording quality than I would’ve wanted. For ep 2, the individual recordings are better thanks to better equipment (new mics, quieter computer).

Stop me anywhere if I pass something you miss. I’m going at full steam until I get a sense of how you’re working. I sometimes use abbreviations that lose people.

Are you doing all your work in Mono (one blue wave)? Unless there’s a valid reason for stereo, mono is a really good idea. My podcast test has stereo music and mono voice. I could be talked into mono everything.

You are Exporting WAV copies of everything against the time Audacity goes into the mud unexpectedly and takes your show with it. There is no: “we need to shoot it again.” Just open up your protection copies and keep going.


Dueling posts.

saving the resulting sound file as a WAV.

Oh, so you’re way further along than just beginner. Yes, the one downside of this process is needing each actor to be good at recording. There was a recent poster who wanted to know how to save one of the four sound tracks in his show.


Can you post two twenty-second sound clips here, one from each voice? Mono WAV, scroll down from a forum text window > Upload Attachment. I’m interested in the latest product from each location. Don’t process it. At all.

I wrote a process for audiobooks and it may work for you. They have really tight requirements for sound quality.

As we go.


Thanks, I’ll do that, though I’ll probably only get around to it tomorrow.

If you successfully post enough times, forum moderation drops away and posting speed picks up. We’re still all volunteers, but moderation is an extra step until we’re sure you’re human.

You are human, right?


… well, human-ish.

Anyway, here are the two samples (WAV, mono, zipped so they’re under 2MB). They both include a bit of (supposed) silence, but they’re mostly talk. (1.73 MB) (1.73 MB)

I’ll listen when I get back home.

There are shortform compressors that might be handy. Chris’s Compressor was designed so Chris could listen to opera in the car. It evens out volume variations without seeming to do anything.

More later.


Both of your clips have “rumble” or low pitch tones that aren’t useful. It’s not always environment (heavy trucks driving by). It’s not unusual for some home microphones to make rumble because it’s expensive to remove and nobody can hear it. But it can screw up post production filtering. The corrections take into account sound nobody can hear.

Steve wrote a filter to get rid of it without seriously affecting your voice.

LF Rolloff is called Low Rolloff now, but it’s the same tool.

Ignore SetRMS. That’s for a different job.

Matt has very well behaved track and I would have no trouble making him into an AudioBook except he sounds like he’s recording in a kitchen or empty room. That’s significant because we can’t take echoes out of a sound track. So you and he will never sound like you’re in the same room.

Mega is announcing into a automatic (gamer??) headset or microphone and should probably stop. The volume changes up and down but that doesn’t bother me. The noise level is high FFFFFFFFFFFF, but we can probably deal with that, too. It’s an automatic microphone and that’s deadly.

At the end where Mega stops talking and look what happens to the noise.

“Matt, how are you?” …ffffffffffffffFFFFFFFFFFFF.

Pumping noise is impossible to correct. FFFFF is going to happen every time Mega stops talking to listen to Matt.

I have a headset where I can turn off AGC or Auto Gain Control. Mega should look for his controls.

I guess Matt is using a simple desktop microphone (or possibly built-in) and there is always going to be a presence difference between Mega and Matt. I once played two different people in a show by intentionally using a microphone that way.

There’s no filter for that, either.

So Matt needs to change the room and Mega needs to change the microphone.

No problem.

OK. So I applied LF-Rolloff (or Low Rolloff) to both tracks.

Chris’s Compressor to more or less even out the volume changes and then Limiter to take the peaks down a bit This is a badly cut “podcast” where I cut between the two tracks. It’s in higher quality MP3 because 30 seconds of WAV will not fit.

If that’s close enough, I’ll forward details of how I got there.


And to be clear, I cut between the two tracks for this test. In Real Life, both voice track noises are going to be there all the time. I also cut out the ramp-up in Mega’s noise at the end. That’s going to appear in the mix, too.

As I said in the post, I can even out Mega’s volume and even suppress the constant background hiss. But I can’t do anything about the noise ramp at the end.

Of course, if you’re obsessive enough, you can go into the dialog and manually suppress each one. There are AudioBook people who do that. One show like that should be good to consider a new microphone or an adjustment to the existing one.


Thanks a lot for this - great stuff for me to work from. As mentioned in another thread, I’m having problems installing Chris’ Compressor, but I expect those’ll be resolved before long. I’ll also try out Low Rolloff.

The slight echo in my room was a bit annoying; I switched from a Sennheiser headset, which I used for episode 1, to a Blue Snowball, and while it helped with some issues, it did result in that echo you hear. However, I am looking into ways of dampening the echo, and I’ve ordered a mic screen, which I’m hoping will help.

I have to say, though, that since we’re still new to this and just finding out how we like it, we’ll probably stick to most of the equipment we have and see how we can best tweak the recordings, rather than going out and buying more stuff. If we realise that yes, this is something we want to become more serious about, then we’ll also look into how to improve the infrastructure, at least beyond the beginner-level material we have now. When we get to that point, we will definitely take heed of the other pointers you’ve given us.

When I post a new effect, I don’t bother to select each one.

Effect > Add/Remove > Select All > Enable > OK.

Nobody is going to stop breathing if you don’t go nuts with each and every point. My natural bent is to studio recording, if only because that makes post production and a quality product so much easier.

Matt makes me crazy. Just a little less echo and he could read for AudioBooks.

Furniture Moving blankets are the answer. Forget the computer for a minute. That’s moving blankets on the wall and the desk.

One poster made a “studio” out of home store plastic pipes—that I guess I didn’t post yet. You can make a really small “studio.”
Screen Shot 2017-09-19 at 14.04.11.png
You can bump up your microphone for closer recording and elminate floor and desk vibration at the same time with the book and towel technique.

Doesn’t have to be Stephen King. Any heavy book.

Many tricks.


Last one. This is my test “podcast.” This is a headset microphone, but not a gamer headset. Denise is four time zones that way [pointing east] speaking into her Mac built-in microphone.

The joke is it’s the perfect podcast. We spent the whole time deciding when we were going to have the next podcast.


Thanks, Koz, that gives me a lot to work with. (I just got King’s IT as an e-book. Can I use that as a mic stand to reduce vibrations? :stuck_out_tongue: ) I’m curious how well the mic screen will work in terms of reducing the echo, but the reviews were pretty good and any improvement is an improvement. If necessary, I can then round this off with blankets or similar.

I might implement the tips for the next episode already, but I’ve got an okay edit already. I’m thinking I’ll probably wait until until episode 3 so I can really hear how the audio quality improves from #1 to #2 to #3.

(I just got King’s IT as an e-book. Can I use that as a mic stand to reduce vibrations?

Try it and post back how it works.

That’s the West Virginia Shock Mount with apologies if you’re actually from West Virginia. It’s the combination of high mass (the book) with acoustic mush (the towel). It’s a home translation of actual commercial shock mounts.

The high mass is the microphone itself and the acoustic mush is the black rubber bands holding it up.

And they can be real rubber bands.
Screen Shot 2017-09-20 at 03.47.47.png
That’s one I made with plastic pipes, black paint and US Mail rubber bands. I shot animated movie voice tracks with that—and the moving blankets.

I had a quiet but live room, so all I had to do was kill the echoes. Doesn’t have to be moving blankets. Storage boxes work just fine. I shot a voice track in a storage closet with boxes of paper records and folders. The only reason I had to stop was they turned the room into a production office.

We were not pleased with the fashion of living rooms with bare walls and wood floors. Those look cool but are aggressively hostile to good recording.