How to Record a Podcast With Multiple Mics

If you run a podcast, it’s likely that at some point you will want to use multiple microphones. In fact, at the time of writing, 40% of the top 100 podcasts on Spotify have multiple hosts, and many more regularly have guests. Whether you have multiple hosts or invite guests on to your show, you will want to know how to record a podcast with multiple mics.

The Goal of This Blog Post

There are two main goals of this post. The first is to describe how you can record each voice on your podcast to a separate audio channel for a simplified editing experience. We will cover this topic in detail so that it will be useful no matter which microphones or operating system you are using. The second goal is to explain how to avoid voices spilling over and being picked up by multiple microphones.

Recording Multiple Voices to Separate Channels for Editing

Although just using one microphone seems like a simple solution, in reality, if you are recording multiple voices then you will want to use multiple microphones. Using one mic would record both voices onto the same track whereas using multiple mics allows you to record each voice onto its own track. Having the voices on their own tracks greatly simplifies the editing process after you are done recording.

Avoid Voices Spilling Over and Being Picked Up by Multiple Mics

In addition to describing how to record a podcast with multiple microphones, we will also discuss how to correctly position the microphones in order to prevent voices from spilling over and being picked up by multiple microphones. This spill over would defeat the point of using multiple microphones in the first place as multiple voices would still be recording onto the same track, complicating the editing process.

Determine the Type of Microphones You Are Using

The first step to setting up multiple microphones for your podcast is to determine what type of microphones you are using.

Use the Same Brand of Microphones for Each Voice

Additionally, it is worth noting that you will want to use the same type and brand of microphone for each speaker in order to maintain the same audio quality across multiple hosts or guests.

Most Common Types of Microphones

There are two common types of microphones. There are XLR microphones and USB microphones. It is likely that you will be using one of these.

How to Tell the Difference Between XLR and USB Mics

The easiest way to determine which microphone you have is to look at the cable. USB microphones have a USB cable whereas XLR microphones have an XLR cable with a rounded connector that has 3 pins inside.

Benefits and Disadvantages of XLR and USB Mics

The quality of USB microphones compared to XLR microphones will vary depending on the specific microphones used, but in general, XLR microphones will result in higher quality recordings than those of USB microphones. However, we will still cover how to record a podcast with multiple USB mics.

The upside of a USB microphone is that it can be connected straight to your computer without the need for any other equipment. Whereas, XLR microphones cannot be connected to a computer and will need additional hardware between the microphone and your computer, we will get back to this later.

How to Position Multiple Microphones for Optimal Quality

You should leave enough distance between the microphones to ensure that voices don’t spill over onto multiple microphones. Additionally, most microphones have a Cardioid polar pattern, meaning that they pick up sounds coming from in front of the microphone and ignore sounds coming from directly behind the microphone. Taking this into account, you will want to angle your microphones so that they are back to back, and the speaker should be sitting directly in front of the microphone in order to minimise voices spilling over onto multiple mics. It’s a good idea to test out your setup before recording to check that only one voice is being picked up by each microphone and to make changes as needed based on trial and error to get the perfect setup.

Connecting Multiple Microphones

XLR microphones require additional hardware in order to connect them to your computer while USB microphones do not.

XLR Mics Need Additional Hardware

When recording from one or more XLR microphones, you will need additional hardware to connect the microphone to before it can be connected to your computer. You can use an audio mixer, audio interface, or an audio recorder.

What Is an Audio Mixer

An audio mixer can receive multiple XLR microphones as inputs and will allow you to control the volume of each audio channel separately. The output of the audio mixer will be the combination of all of the input audio channels. Most audio mixers do not have built in memory but some do, so these can be useful for mobile recording setups. The audio mixer is connected to your computer via USB where you can record the single audio channel that is output by the audio mixer. You will need a USB to USB-C adapter if your computer does not have a USB port.

What Is an Audio Interface

An audio interface is used to connect the XLR microphones to your computer by converting the analogue audio signals produced by the mics to a digital signal that can be understood by the computer.

What Is a Digital Recorder (Audio Recorder)

A digital recorder, also known as an audio recorder, is a hardware device that is built specifically for recording audio. They may have a built-in microphone or XLR inputs that can be used for your XLR microphones. This option is useful for mobile setups as it doesn’t require a computer to actually record the audio.

Which One Should You Use

So out of these three options, you are probably wondering which one you should use when recording multiple voices for your podcast. The answer is that you don’t want to use an audio mixer due to the fact that it combines the audio channels into one output which makes editing the voices more challenging and means that you have to get the audio levels right during the recording process. Out of the other two options, the right one for you depends on your requirements as there are pros and cons to both as we will discuss now.

Best for Editing

As mentioned already, an audio mixer makes editing more difficult as all of the audio channels from the different voices will be combined into one audio channel before being outputted by the audio mixer. You will want to double check your digital recorder to make sure that it records each audio channel separately, if it does, then this is a good option alongside an audio interface which outputs the separate audio channels having converted them to digital signals for your computer to understand. So both digital recorders and audio interfaces are good options for an easy editing process.

Best for Mobile Usage

As the digital recorder has been ruled out due to the fact that it combines all of the audio channels into one output channel making editing more difficult, we will focus on comparing audio interfaces and digital recorders. If you need a mobile setup for recording your podcast then the digital recorder is a great option as you can get one with multiple XLR inputs that records the audio as separate channels directly onto the digital recorder without the need for a computer. Whereas, the audio interface will require that you have a computer to connect it to in order to record the digital audio channels that it outputs.

Best for Use in a Studio

If you know that you are always going to be in a studio when you are recording your show then you may prefer to go with an audio interface. This way you can feed the analogue audio channels from your XLR microphones into the audio interface and then simply take the digital audio channels outputted the audio interface and feed them straight into your computer via USB. Using an audio interface like this, means that you don’t need to transfer the recording from the digital recorder onto your laptop as it will just be recorded straight onto it instead, removing the file transfer step.

USB Mics Can Connect Straight to Your Computer

The benefit of using a USB microphone over an XLR microphone is that you can connect it straight to your computer without the need to purchase any additional equipment. However, when it comes to figuring out how to record a podcast with multiple USB mics, it gets a little more complicated.

Which Features to Look For in a USB Microphone

So maybe you have decided that you are going to go for the simpler option and use a few USB microphones that you can connect straight to you computer to the record the audio from multiple hosts or guests. But now you are wondering which specific USB microphone you should get. Read on to find out which features you should look out for when choosing a USB microphone.

Built-in Preamp

An amplifier is an electronic device that increases the strength of a signal. When applied to audio, this simply refers to the process of increasing the volume of the audio signal. A preamp, or preamplifier in full, is a specific type of amplifier that takes a particularly weak signal, such as that of a microphone, and makes it stronger so that it can be processed correctly. Ideally, you will want to look for a USB microphone that has a built-in preamplifier. Most USB microphones come with one so it shouldn’t be difficult to find one that you like.

Built-in Digital Converter

A digital converter is an electrical circuit that convert an analogue signal into a digital signal. They may also be called simply, analogue-to-digital converters (ADCs). These are the same circuits that are used in an audio interface as was mentioned earlier when talking about XLR microphones. This conversion is needed as your computer can only understand a digital signal, and not the analogue signal produced by the microphone. So you will want to find a USB microphone that has a digital converter built-in, and the good news is that most USB microphones have one.

USB Port Adaptors

Take into consideration the fact that you may need an adaptor if you are going to be connecting multiple USB microphones to your computer. You may need an adapter if your computer doesn’t have any USB ports or if it doesn’t have enough for each of your USB microphones. In this case, you can purchase a USB hub or a USB-C hub to increase the number of available USB ports.

Sound Cards Can’t Record Multiple USB Microphones

However, that is not the end of the story when it comes to connecting multiple USB microphones to your computer. There is another issue in that most sound cards in computers won’t be able to record the audio from multiple USB microphones. We will go through the solutions to this issue.

Multiple Computers

One solution to this problem is to record the audio for each USB microphone onto a separate computer. This way, each sound card on each computer only has to handle one audio channel. Maybe this will work for you, but there is a good chance that you don’t want to have multiple computers for each of your hosts or guests so we will continue to explore more options for handling multiple USB mics below.

Create an Aggregate Device

If you have access to MacOS then you can record multiple USB mics using just one computer with the help of an aggregate device. An aggregate device is a piece of software that comes with MacOS and allows you to use multiple devices at the same time with a number of audio applications, including recording software. This way, you can record audio from multiple USB microphones and maintain the separate audio channels for each speaker, making editing much more straight forward.

MacOS Audio MIDI Setup

The steps for setting up an aggregate device on MacOS are:

  1. Connect all of your USB microphones to your computer, using adapters if necessary.
  2. Use Spotlight Search to open the “Audio MIDI Setup” application.
  3. The Audio Devices window should be open, click the plus icon at the bottom of the window and select “Create Aggregate Device”.
  4. You can double click the device to rename it once it is created.
  5. Select the new aggregate device in the sidebar and check the “Use” checkbox for each of the USB microphones that you want to record from.
  6. If you are aware that one of your microphones has a more reliable clock than the others then you should select that one as the clock source from the dropdown. This devices’ clock will be used to synchronise all of the microphones.
  7. Select drift correction for each of the USB microphones that is not selected as the clock source. This feature will keep your microphones in sync by compensating for the small differences in the rates of each of the clocks found in your USB microphones.

The channel numbers that you can see for your USB microphones in the Audio MIDI Setup application correspond to the numbers that will show up for each audio channel when you select this aggregate device in your recording software. We will discuss editing later.

Windows Setup

Windows does not come with software for creating an aggregate device as MacOS does, but there is recording software that you can use to record multiple audio sources onto separate tracks as we will discuss in the section on recording.

Recording and Editing Multiple Audio Streams

When thinking about how to record a podcast with multiple mics, there are a few important things to consider in order to make the editing process as straight forward as possible.

Use a Separate Channel for Each Microphone

As mentioned before, you should record each of your audio sources as separate audio channels as this makes editing your podcast episodes much simpler since you can edit each speaker separately.

Use Software That Supports Multi-Track Recording

Now that you have connected multiple USB microphones to your computer and set up an aggregate device on MacOS, you can move on to recording these audio channels using GarageBand on MacOS. We will cover a Windows solution next.

The steps for recording to multiple tracks with your Aggregate Device and GarageBand are:

  1. Go to GarageBand, then click Settings or Preferences.
  2. Click the Input Device pop-up menu, then select Aggregate Device.
  3. Create new audio tracks for each of your USB microphones.
  4. Option-click each track header and select Configure Track Header, then select Record Enable. This will add the record enable button to each track header.
  5. Select the track header for one of your tracks, then click Track in the Smart Controls pane at the bottom of the window.
  6. In the Smart Controls pane, click Recording Settings, then click the input button to set the audio channel to mono or stereo depending on the microphone you’re using.
  7. Click the input pop-up menu and select one of your microphones from the dropdown. The numbers correspond to the numbers given to the audio channels in the Audio MIDI Setup application as discussed earlier.
  8. Repeat steps 5, 6, and 7 for each of your tracks so that all of your microphones have their own channel to be recorded onto.
  9. Click Record Enable in the track header of each your tracks.
  10. Click the red Record button in the toolbar to start recording.

Recording to Multiple Tracks With USB Mics on Windows

On Windows you can use recording software that supports recording multiple audio inputs to their own channels. This includes any software that is ASIO enabled. ASIO stands for Audio Stream Input Output and it allows software on Windows to interface directly with hardware devices such as your microphones. For instance, you could use Reaper, Adobe Audition, or Pro Tools to record to multiple audio tracks from your USB mics. This is preferable over solutions that mix the audio channels into one channel for recording as having the separate channels recorded makes editing easier as mentioned before.

These are the steps for recording to multiple tracks with ASIO and Reaper:

  1. Install the ASIO drivers from ASIO4ALL.org, a driver is simply some software that lets the operating system communicate with a hardware device such as your microphone.
  2. Restart your computer after the ASIO drivers have finished installing.
  3. The process is similar for all editing software that supports ASIO drivers. If using Reaper, go to Options, then Preferences, and click on Device in the sidebar.
  4. Change the Audio System to ASIO using the dropdown.
  5. The ASIO Driver option should have ASIO4ALL selected.
  6. Click on the ASIO Configuration button and enable your USB microphones in the device list that opens in a new window.
  7. Check the Enable Inputs checkbox.
  8. Select the first and last of your USB microphones in the order that they appear in the drop-downs below the checkbox.
  9. Right click and select Insert New Track in the left pane of Reaper to create a new track for each of your microphones.
  10. Right click on one of the tracks in this pane and click on Track Manager to set the names of your audio tracks.
  11. Click on the red circle on a track to arm it for recording, this means that when you click record, the audio will be recorded to this track. This feature is used to prevent recording over audio unintentionally. Do this for each of your tracks.
  12. Use the “IN FX” dropdown that appears, to select the recording type and microphone to record from. Do this for each of your tracks.
  13. Click the bigger red record button below the tracks to start recording all of your USB microphones onto their own tracks.

Conclusion and Summary

In summary, if you want to record a podcast with multiple mics then you should record to multiple tracks for ease of editing. You have the option of using XLR or USB mics. If using XLR mics in a studio environment, you will want to use an audio interface to connect your mics to your computer. For a mobile setup, you may want to use an audio recorder instead.

In order to record to multiple tracks with USB mics on MacOS, you will need to create an Aggregate Device using Audio MIDI Setup and you can use GarageBand for recording. If you are using USB mics and want to record each to its own track on Windows then you can use any ASIO enabled software.

Finally, once your XLR or USB mics are connected and ready for recording, remember to space the microphones apart and angle them back to back with each host or guest speaking directly into their microphone.

References

Spotify. (n.d.). The podcast charts. Spotify. Retrieved January 17, 2024, from https://podcastcharts.byspotify.com/

Apple. (n.d.). Create an Aggregate Device to combine multiple audio devices. Apple Support. Retrieved January 17, 2024, from https://support.apple.com/en-gb/HT202000