Recording Your Lectures 1: the one thing your can do to improve your students’ listening experience

Tl;dr:
Hang a blanket, quilt, or something else that’s absorbent behind you while you make your lecture recordings.

That’s it.

A whole lot of people are going to be audio recording their university lectures in the fall, or delivering lectures live over Zoom. This series of tutorials will give you some easy steps to make them better.

Students are going to spend hours listening to recorded lectures. It’s going to be difficult for them. Some small improvements in sound will make a huge difference in their experience of your course.

The most important thing you can do for the sound of your lectures is to reduce the room echo that people will hear in your recordings.

After months of Zoom meetings, I can tell you that many people deliver lectures from echo-y spaces. The current fashion for sparse decoration, and hard wood floors means that sound bounces around the room a lot.

The problem with echo is this: If you record yourself with a lot of echo, your words are less clear. It’s like doing course readings from a bad photocopy with blurry font (#gradschoolflashback). If your students have trouble hearing you, they have to turn you up more, which also amplifies all the echo in your room, which means they have to turn you up even more. Pretty soon they are blasting their ears. Now multiply that by 5 classes by 160 minutes a week. Brutal.

The solution: Luckily, this is easy and low tech to fix. You do not need fancy room treatment (unless you are a nerd like me and doing other audio recording).

You just need something behind you that absorbs sound. One inexpensive solution is a moving blanket or thick quilt. A Canadian Tire moving blanket will set you back about $20 (Canadian). You will want to hang this a couple feet behind you, about a bit higher than your head while sitting in the position where you will record. Anything can be used to hang it: a clothes rack will work just fine. Just make sure it’s hanging behind you and the mic.

Why this helps: Reverb comes from sound reflecting around a room. Your microphone tends to pick up sound coming from behind you.* By having something to absorb the sound, you get less echo in your mic, which is then less amplified by the software, which makes your words clearer, which means that students don’t have to work as hard to hear you, which makes your lectures easier to understand.

But this isn’t a perfect solution. This will not get you perfect acoustics, but it will greatly improve the sound your students hear. You can move the blanket around and position yourself as you like and try different approaches. It is worth messing around a bit to find a sound you like for your voice. Then just do it every time and forget about it.

Bonus round: If sound absorption is the goal, and fabric absorbs a lot of sound, should I record in a closet where all my clothes are hanging? Ask yourself if you want to record a semester’s worth of lectures from inside a closet. I believe the answer is a hard no.

An alternative solution: Some kinds of microphones pick up less room sound. These are particularly good for voice recording (and are often used in radio). If you use one, room sound is less important. The mics in laptops are just fine for recording your voice, but they do tend to get a lot of room sound because of how they operate. I will cover this in my microphones tutorial.

Next up: how to actually make the recordings with a minimum of fuss, and what to do when you screw up.

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*not true for all microphones, but that will be covered in a later microphone post