Before getting into the nitty-gritty, I just want to say that while there’s nothing wrong with connecting your mic directly into the camera for filming things like interviews - assuming you have a good camera with the right connections - in my opinion, working with external recorders gives you so much more control over the quality of the audio you’re capturing while also opening up the possibilities as to what kind of video-audio work you can do. I always advocate for external recorders when possible, including on-camera wireless mics like these great ones from RODE.
There are many kinds of portable recorders out there, from various brands with different features and for varying budgets! I’ll admit now I’m a bit of a Zoom fanboy, but everything we’re going to go over here applies to just about any higher-end recorder you come across, be it Zoom, Tascam, Sony, etc. They all work great and can really take your audio recordings to the next level.
While it’s easy and super tempting to just turn the thing on and hit record, this blog offers a quick crash course on why you shouldn’t do that and how to avoid common mistakes when using external recorders, especially when you’re starting out.
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Monitor your Audio with Good Headphones
Nothing is more frustrating than going out to film a great interview or podcast, only to realize afterward that your audio is terrible. This can be due to several reasons, such as distracting background noise or poor levels, issues that could have easily been avoided if you were monitoring your audio. The best way to do that is with a good set of headphones (NOT earbuds).
I’m also an Audio Technica fanboy, so I recommend anything from their M series line of headphones for production work. For anyone who may be thinking they don’t need headphones and can rely on the little sound meters on the screen, yes, while they do show you that sound is being detected, only your ears can tell you what that sound is!
On that note, many recorders also have a 3.5mm mic jack that can be confused for a headphone jack if you’re not careful, so make sure your headphones are plugged into the correct connection.
Using the Right Microphone Input
Many higher-end recorders feature multiple mic options for recording, so you have to make sure you’re actually recording with the proper mic. Let’s look at the ZOOM H4N as an example. You can either use the built-in mics featured on the top of the recorder, or you can connect another external mic to the bottom using an XLR cable.
But before you hit record, you have to make sure you set the recorder to the right input; otherwise, you may think you’re recording with the shotgun mic while the recorder is actually still using the built-in mic. On this particular recorder, you can easily switch between mics with these useful little buttons on the front.
This is also another one of those issues you can easily avoid by MONITORING your audio.
Volume vs Gain
Probably the most common mistake I’ve seen (and one I’ve committed my fair share of many times when I was starting out) is raising the volume on the recorder rather than the gain when trying to get a louder signal.
What’s the difference? Simply put, Gain is how much amplification you add to your audio signal once it’s going through the preamp (or preamplifier) in your recorder, while Volume is the strength (or loudness) of the output, like speakers or headphones.
So let’s look at an example of volume vs gain in a real situation:
Let’s say you’re filming an interview with a shotgun mic attached to an external recorder, and your talent is very soft-spoken and a little hard to hear clearly. If you raise the volume on the recorder, your talent will sound louder to you at the moment, but the resulting audio file afterwards will still be low because you didn’t affect the audio signal itself; you just raised the volume in your headphones. On the other hand, if you raise the gain, you’ll increase the strength of the signal itself and end up with a louder audio file, and that makes all the difference.
My personal rule of thumb is to try and have the gain set to a level where your talent’s voice is somewhere between -18 and -12 dB when speaking normally and peaking at around -6 for sudden loud spikes, like laughter. That gives you plenty of room in post to mess with the levels as needed. After that, you can set the headphone volume to a comfortable listening level.
Please keep in mind that these settings aren’t universal, and there are other factors to keep in mind such as mic sensitivity, the talent’s distance from the mic, the quality of your recorder’s preamps (which can introduce noise into your recording if excessive gain is used), and how loud the recording environment is.
For an extra level of “control”, you could also try moving the mic closer or farther away from your talent or even ask them to talk louder or softer, though your mileage will vary here.
If for whatever reason your recorder has both volume and gain labeled differently, all these principles remain the same.
Sample Rate and Bit Depth
So let’s think back to earlier when we went over Sample Rate and Bit Depth. We kind of compared them to the “frame rate and resolution” of video, right? With that in mind, you should always check and set your Sample Rate and Bit Depth to the appropriate settings, just like you would set the frame rate and resolution on your camera while getting ready for a shoot.
So if you’re recording for video, 48kHz at 24-bits is the go-to, but you have more wiggle room for audio-only products if you need it. Like almost everything else we’ve talked about, it just depends on your specific needs.
Limiters and Compressors
Some recorders may have an option for Compressors and Limiters, which are both audio processing tools that affect the amplitude of your audio. Very simply put, Limiters will not allow the audio to go above a specified dB threshold (aka, not letting it go past -3dB, for example), to avoid distortion and clips. A Compressor, on the other hand, lessens the Dynamic Range of your audio by reducing the amplitude of the louder parts of the signal (aka, making louder parts softer) and making the audio sound more “even.”
Put even more simply, Compressors lower loud volumes, and Limiters stop them from getting too loud in the first place. There’s more to be said and explored about compressors and limiters, but this is generally what they do and is a good introduction for those starting out.
Compressors and Limiters are useful tools for both technical and artistic purposes, such as getting rid of loud peaks in your audio or balancing vocals in a song. Activating them while recording applies the effects to the audio right then and there in real time, while digital limiters found in DAWs apply the effects later in post-production. Personally, I like working with the digital limiters and compressors in my DAW, but different goals and workflows for different types of projects and creators.
Extreme use of either tool, however, can really junk-up your audio, for lack of a better term, so be mindful when applying them and try experimenting beforehand.
Batteries and Phantom Power
Phantom Power is an electrical current that runs from the recorder or board to your mic to provide it with power, but ONLY IF it needs it.
Not all microphones require phantom power. Dynamic mics, for example, generate their own power, while condenser mics do not and need an external power source, like phantom power or a battery. Phantom Power is usually labeled as 48v (or 48 volts) on your recorder and needs to be manually turned on and off as necessary.
On that note, always, always, always have backup batteries for your external recorder, especially when you’re recording outside or in some other remote environment with no wall outlets, and extra especially if you’re using phantom power. Believe me, your day will be ruined if you’re out in the middle of the desert filming a short film, and the recorder dies on you halfway through and you have no backup batteries. This is an actual real-life example that happened to me when I was a student.
All this applies to cameras as well, and whenever possible just connect to a wall outlet if you have the option. Why needlessly drain your batteries if you can easily connect, right?
SD Cards and Storage
The same goes for SD cards and storage! Different recorders have different SD card needs and specifications. Some older models won’t take a card larger than 32GB, while some models do. Always check your recorder specs before getting an SD card to make sure you’re buying compatible equipment. Look for card size limits, writing speeds, etc.
I’d also recommend regularly backing up and deleting your audio files. It’s pretty annoying when you need to stop recording to go through and delete your files one at a time to make room for your current project.
Conclusion
This wasn’t too bad, right? If you keep these simple and easy-to-remember items in mind when you’re out recording, you’ll easily avoid a lot of pitfalls so many of us fall into when we’re starting out.
As always, let me know if you found this helpful, hated everything about it, or have any feedback. I'm always happy to chat!
-A