A Brief Guide to Common Podcast Microphones

As an audio engineer it's my dream to be always working in a studio with broadcast quality microphones, and indeed that was most of my experience in radio. Podcasting is not the same. A lot of recordings are made at home or in the field which isn't bad, it's just different. A lot of the work I do is people sharing pretty personal stories, and being able to record at home is not just a convenience, it can mean that people feel more comfortable. You can set up a broadcast microphone and an audio interface at home, but managing that tech might be too complicated for a lot of guests, or it might make them so nervous that they can't express themselves in the interview. The most important part of any recording is the content, and if recording using something simple at home is what's needed for that interview then it's the best option.

An understanding of the technology means that you can get the most out of whatever microphone you're using, no matter how cheap and cheerful. To that end I have created a short guide for recording with common microphones.

Just as a general note, you should always be recording with headphones for every person, and I am creating this guide with that assumption.

Vocal microphone/broadcast microphone

This section is a repeat of what I've written in my book but it's a good starting point.

Your basic vocal microphone (eg Shure SM58, Sennheiser e945) or broadcast microphone (Shure SM7B, EV RE20) is a dynamic, end-address microphone. They typically have a cardioid pickup pattern, or something similar. They're easy to use and they don't pick up much background noise, mouth noise, sibilance, or plosives. If someone shows up with one of these you're going to have a good day.

These microphones typically plug into an audio interface but there are modern models that directly plug into a USB port such as the Shure MV7.

Starting position

Ask the person to position their microphone about a fist's distance from their mouth at a 45º angle. It should be pointing at the mouth but out of the way of the breath (see image).

Typical issues

• Positioning too close to the mouth. People might do this to take advantage of the proximity effect (which will make their voice sound deeper), but it might also pick up excessive mouth noise, sibilance and plosives.

• If the mic is a good distance but you're picking up sibilance or plosives try changing the angle of the microphone. Sibilance can come from just one section of a person's mouth (eg on the left shooting downwards), so try to find the area of worst sibilance and move away from there.

• The mic might have switches that you need to take note of. For example the SM7B has switches that enable a bass roll-off and a presence boost for vocals. 

Condenser microphone

Condenser microphones sound great, except they're very sensitive. They pick up a lot of background noise, reverb, sibilance, plosives, mouth noise and spill. If I were recording a singular professional performer in a studio I might very well choose a condenser, but they are less suitable for recording with amateurs at home.

Starting position

Similar to the dynamic microphone, except it should be an open hand away (thumb to pinky finger), not a closed fist. Make sure that the person is recording in a quiet room without too many hard surfaces.

Condenser microphones need phantom power so if you're not getting any signal from them check that (but not if USB mic).

Typical issues

• Positioning too far away, which will pick up excessive background noise.

• Positioning too close which will pick up mouth noise, sibilance and plosives. Try positioning it further away or angling it. A pop filter will also help with these issues.

• If it's a side-address microphone people might speak into the back of it. The front is typically the side with the logo on it, or sometimes there's a small gold disc indicating the front. The manual will tell you which side is the front.

• If the microphone has multiple polar patterns available the user might have selected the wrong one. You'll want to choose cardioid. If you choose omni or figure 8 when recording in front of a computer you'll pick up a lot of noise.

• All microphones will pick up sound when a person hits the desk, but these microphones are particularly sensitive to it. They might even be sensitive enough to pick up the vibrations coming from a computer. A spider shock mount will isolate the microphone from kinetic sound.

• If it's a side-address microphone and its picking up excessive sibilance you can try to dull it by attaching a pencil to the outside of the microphone with a rubber band in line with the diaphragm, which is the disc that you'll be able to see through the grill. See image below.

Source: Sound on Sound article Managing Sibilance'

Shotgun microphone

A shotgun microphone is a type of condenser with a highly-directional polar pattern, meaning that it picks up sound from a very small area at the front and rejects a lot of background noise. They are much more suitable for recording in a noisy space such as the home than a typical condenser. Shotgun mics can sound a bit thin, but really good ones sound great. 

Starting position

Similar to the dynamic mic: ask the person to position their microphone about a fist's distance from their mouth at a 45º angle. It should be pointing at the mouth but out of the way of the breath.

Like any condenser, a shotgun microphone will need phantom power to operate.

Typical issues

• When using a shotgun microphone a person needs to pay particular attention to stay on mic. It will help if they can hear themselves through headphones.

USB mics

USB microphones might be dynamics, they might be condensers, they might be electret condensers (in which case they will sound pretty cheap and tinny). The most common USB microphones used in podcasting are the Blue Yeti series, so if you're working with a lot of different people I would highly recommended reading the manual to familiarise yourself with these microphones.

An affordable USB microphone that I like is the Samson Q2U, which is a dynamic. It has an audible noise floor but this responds well to noise reduction.

Starting position

As above, depending on whether they're dynamics or condensers. USB microphones tend to come with a very short stand, but you can get the user to raise up the microphone with a pile of books or whatever.

Typical issues

• Typically you need to plug headphones straight into a USB microphone because most computers can only handle one audio interface (due to only having one internal clock, and the interface taking samples per second). 

• A Yeti has a headphones control on the side which many people mistake for a gain control. You need to adjust the input gain on most USB mics through the computer settings

• USB microphones can come with a wild array of features such as gates or exciters. You want to familiarise yourself with the features of a particular microphone and instruct the user on which ones they should select.

• Sometimes a dynamic USB microphone won't pick up enough signal. Asking someone to talk louder is ineffective because they'll forget once they get into the flow of talking, but you can get someone to consistently talk louder by turning down their headphones.

Headsets

Headsets are not the worst, actually. The audio quality is typically not great, but at least they don't pick up too much background noise. Headsets can be the solution for a person who moves around a lot when they talk and can't remember to stay on mic.

I don’t recommend recording your podcast with a USB headset, but if money’s tight then the Kensington Hi-Fi USB-C Headphones with Mic is surprisingly OK.

Starting position

Position the microphone so that it's just above the person's lips. If you have control over the distance of the headset from the mouth then I'd say about three fingers away.

Typical issues

• Listen for heavy nose breathing when laughing, crying or sighing. Sometimes a person will dramatically sigh if they think you're taking too long to set up, but laughter is actually the best of these three options because it's the loudest. If you’re having trouble getting someone to laugh then ask them to tell a joke and they’ll laugh at their own punch line. If the person is a heavy nose breather, or a snorter, then try positioning the mic below the mouth, though that could cause excessive sibilance. 

• Sibilance: sometimes a person creates more sibilance from one side of their mouth. Some headsets can be reversed. 

• Too much mouth noise: move the mic further away from the mouth.

• Headsets can be uncomfortable. There’s not a great deal that you can do about this, but if the cable is what’s causing the issue (and you’ll know because the person will start fiddling with it) then you can position the cable behind the shoulder. If a person adjusts the headset mid-interview and they position the microphone poorly then you can stop the recording at a suitable moment and correct it.

Bluetooth headset

These aren't great, but they're better than nothing.

Starting position

In the ear or over the ear depending on how its designed.

Typical issues

• Bluetooth headsets are really small meaning that the headphone is really close to the microphone, so when you're using it you should turn on acoustic echo cancellation, but know that acoustic cancellation will punch holes in the audio if two people speak at once. This means that you can’t delete or space out interruptions in post production.

• Sometimes the sample rate of the bluetooth headset is really low which means that it won't calibrate with the sample rate of the recording software. There's nothing you can do, you just need to use a different mic.

Earbuds with built in microphone

Guests who use earbuds when recording podcasts can be very dismissive in sound check. They tend to believe you can fix anything in post.

Starting position

Both earbuds in the ears, microphone hanging loose and unobstructed.

Typical issues

• People picking up the microphone and bringing it to their mouth. All lavalier mics are tuned to be extra bright to make up for the fact that your chin is blocking the sound. If a person moves the microphone to their mouth then the recording will sound extra sharp. If they keep moving it around you’ll have changes in both volume and frequency response.

• Fiddling with the cord. Get the person to fiddle with something else, preferably something silent, like an eraser.

• Leaving one earbud hanging loose so it sits near the microphone causing echo. Don't.

• Excessive head movements causing the microphone to swing around and hit things. Don't. Actually it's really hard for some people to remember to sit still so it might be time for a different mic.

• There are three connection points on a headset: tip, ring, and mic (sleeve is the shielding). If you're not getting a stereo signal or you're not picking up the mic signal try getting the guest to turn the plug in the socket for a better connection. It's the classic audio engineer's jiggle.

Laptop mic

People who turn up to recordings with nothing but the laptop mic are at least usually apologetic about it.

Starting position

Make sure that the laptop is on a solid surface and not moving. If the guest doesn't have headphones ask them if they can find a pair. If not then turn acoustic echo cancellation on. Laptop mics can pick up a lot of background noise and reverb so make sure the guest is using the laptop in a quiet room, preferably one with a lot of soft furnishings.

Typical issues

• Placing the laptop on a surface that is moving (eg a bed) causing the computer to have to constantly re-calibrate the acoustic echo cancellation, resulting in echo.