Quick and cheap audio editing for online courses

A family member is a college professor and her courses this fall will be held virtually. Her lectures will be recorded ahead of time and she asked me for some tips to be more productive.

Much of this will be for the tools that she is using, Microsoft Powerpoint and Techsmith Camtasia, but the general ideas work for most tools.

Use a decent microphone. You can go crazy and spend a lot of money on microphones and associated gear, but you can get very good results with a decent USB microphone.

The Blue Yeti microphone is a good choice. It has a stand and you can control the pickup pattern that it uses. The pickup pattern is important, you just want to pick up your voice and nothing else. Amazon.

The HyperX QuadCast microphone is another good choice. Designed for gamers, it has configurable pickup patterns, a built-in pop filter, and a stand. It also comes with a built-in shock mount. That will filter out any sounds that would be transmitted through your desk. Amazon.

The RØDE NT-USB is another good USB microphone that comes with a stand. Amazon. I use its big brother, the RØDE Podcaster. B&H.

You’ll probably want to use a pop filter with your microphone. Put your hand in front of your mouth and then say the letter “L”, followed by the letter “P”. Did you feel more air move when you said “P”?  That’s because the effort to say “P” is a plosive speech sound. Without a pop filter, that rush of air will get picked up by the microphone.

Depending on what comes with the microphone, you may or may not need an external pop filter. You can usually find a decent one that clips to the microphone or stand for $15-$20 dollars.

To get a consistent sound, you’ll want to record in the same place. Every room has different acoustics and it’s jarring to the audience to hear changes in the sound.

You’ll want to deaden the sound, basically remove any echos. If your room has bare walls, your voice will bounce around a bit. I have acoustic panels in my office, they help a lot. You can make your own, it’s basically linen fabric wrapped around insulation, inside a wood frame.  If you are doing a lot of recording, you may want to look into doing that as a DIY project. 

If you can hang up blankets or quilts around you, that will work just as well. And quilts hanging on the wall will look much better than acoustic panels.

The quilting wall in my wife’s home office helps dampen the sound for her Zoom calls.

Get in the habit of speaking into the microphone at the same location and angle. That will help get a consistent sound.

Also, you’ll want to record and edit your audio with a nice set of comfortable headphones. This will allow you to hear exactly what you recorded and filter out everything else that is going on.

I love Camtasia, but the audio editing tools are less evolved than the video editing tools. What I do is to record and edit the audio separately. We’ll be using Audacity here. Audacity is a free and open-source audio editing tool that is available on multiple platforms. You can get it here. Go install it now, I’ll wait.

You can record your audio directly with Audacity or you can take existing audio from a Camtasia project. Either way, you can clean up the audio in less time than it would from within Camtasia.

If you recorded the audio and video together, you can separate the audio and video tracks from within Camtasia. Once you have the clip loaded on the timeline, right-click on the clip and select “Separate Audio and Video”. You’ll now have individual audio and video tracks. 

If you go to the Share menu, you can select “Export Audio Only…”. Save the file as a .wav file. Now you can open the file in Audacity. When you open the file it may give you a warning about choosing an import method. Audacity can either work with a copy of the file or edit it directly. Either way will work.

Warning message from Audacity

Once you have the file opened in Audacity, we can reduce the background noise. Select a section of the file where you are not talking. From the Effect menu, select “Noise Reduction…”.

Selecting the Noise Reduction effect for the selected audio

Once you have the file opened in Audacity, we can reduce the background noise. If you don’t have a lot of background noise, you can skip this step. Select a section of the file where you are not talking. From the Effect menu, select “Noise Reduction…”.

A dialog will open up. Click the “Get Noise Profile” button. It will scan the selected clip and build a noise profile. Then, select the entire clip (press Ctrl-A) and select “Noise Reduction…” from the Effect menu. This time, press the “Ok” button.

The Noise Reduction effect

Now you can normalize the volume in Audacity. This will allow your narration to have the same volume for every clip. You can select Normalize from the effects menu. You set it at a maximum db level. Your peak should be at -6 db. You can go lower, like -8 db, but you once you pick that level, that’s the level you want to use for the entire video. If someone else will be mastering the audio afterward, find out what level they want you to use.

The Normalize effect

And that is the peak level, the overall audio should be in the range from -9db to -18 db. You can use the normalize filter to set the level so that the peak is at -6db. This will raise all of the levels, including pops, clicks, and other noises in the recording in between your words. That makes it easier to find and remove them.

The Hard Limit option of the Limiter effect

If your voice has a lot of dynamic range, you may find that setting the peaks to -6db doesn’t raise the rest of your voice enough. What you can do is to raise the level higher, to say -3db. Then run the hard limiter filter at -6db. That will clip the peaks to -6db and the net effect is that your voice will sounder louder.

Once you have the audio level set, you want to remove any and all sounds in between your words  Not every word, just in the pauses. Select that section so that it’s highlighted and press the Ctrl-L key combination  That will silence that section. You still want to do this after running the noise reduction filter.

To make your time more efficient in Audacity, you can assign keyboard shortcuts to the filters that you used the most. If you open up the Audacity preferences, from the Edit menu or by pressing CTRL-P, you can select “Keyboard” and edit the key bindings. I assigned the CTRL-8, CTRL-9, and CTRL-0 shortcuts to the Noise Reduction, Normalize, and Limiter filters. Those shortcuts were not being used, and they are easy to remember.

Keyboard shortcuts, use them

If you find that your voice has “click” sounds, you’ll want to remove as many of them as you can. There is a de-click effect with Audacity, but I haven’t had much luck with it. I use a program called RX 7 Essentials from Izotrope that does a nice job of removing the clicks out of my voice. It retails for $129, but they run sales from time to time. Two weeks ago, I paid $29 for it. There is 50% education discount on their site. If you are doing a lot of videos, this can save you a lot of time. If you have this tool, you may not even need to use Audacity.

RX Essentials with the De-click dialog

Once you are done cleaning up the audio, you can import it into Camtasia as a media file. Drop it on the timeline in a track above the existing audio track. That will make it easier to line it up in place. Once you have it in the right place, you can just delete the original audio track from the timeline.

If you are doing a presentation that is a series of Powerpoint slides, you’ll want a second of silence in between each slide. Basically, a half-second at the end of one slide, then another half-second at the start of the next slide. You can use the Camtasia tools to measure a 1 one-second clip, but a friend shared a quick way to this. 

Record a one second of silence audio file. Add it to your Camtasia project. At the end of the audio for a slide, add the one-second clip to the timeline. If each slide is it’s one video clip, extend the end of the clip to the halfway position of the one-second clip. Then place the next slide’s clip next to the previous slide on the timeline. If you need a copy of a one-second clip, I put one here that you can download.

If your slides are in a single clip, split the clip at the end of the first slide. Move the timeline cursor to that position and press the “s” key. That will split the clip at that point. You can then drag the of the clip to the halfway point. Make sure to hold the ALT key down when dragging the edge of the clip. That extends the last frame of the clip.

One more tip for Camtasia. Turn off the preferences setting for “Auto-normalize Loudness”. It’s hidden under the Projects tab in the Windows version of Camtasia and defaults to being on for new installations. You’ll want to disable this feature.

If you are following your own script and you have a sentence that you keeping mangling when you try to say, there are a couple of things to try. One is to keep saying it until you get it right. Another thing is to change the wording. What looks good written down may, for whatever reason, fail to flow off your tongue.

Another thing that you do is to pause during the sentence that is killing you. Say part of the sentence, pause, then continue with the rest. You can use the audio editing tools to clip out the pauses so it sounds more natural.

If you need to embed a link in your video and you just have a video file, use a QR code and let them scan the code with their phone. There are tons of free QR code generators on the Internet. I used QRCode Monkey to create the following QR code and placed into a Powerpoint slide.

Scan it with your phone’s camera, it’s just my Twitter timeline

They give you a fair amount of tweaking to the QR code format. If you do something like this, add a 5-second pause and tell people to pause the video while they scan the code with their phone.

And that’s the budget-friendly way of getting a better sound out of your narration.