You’ve made the exciting and laudable choice to pick up a high quality DSLR or mirrorless interchangeable-lens camera. Nice! You’re taking better photos more easily than ever, exploring creative modes, and (if you made your purchase with us) you’re enjoying all the Perfect Picture Pak has to offer… but something seems off about your video. It just doesn’t feel quite as professional as those photos have been looking.
The likely culprit? Less-than-impressive audio! Image quality is crucial, of course, but it’s only a part of the picture. To create a truly professional feeling video (ironically enough) audio quality can actually be more important. It’s a non-intuitive problem for the aspiring film-maker, especially because, unfortunately, it’s not one you can solve through settings and technique alone.
Let’s clear up any confusion about that right away: this is not a tutorial for getting great audio using only your DSLR or mirrorless camera. The built-in microphone—regardless of brand or model—is usable at best for recording a single voice at close range in an otherwise silent room. In conditions any more challenging, the limitations of built-in audio recording quickly become evident to any aspiring videographer. Even using the built-in mic to record a reference track for syncing is questionable in some environments.
Internal microphones are usually not great in DSLRs/ILCs for a few reasons (aside from the fact that they are still primarily visual-capture devices). For one, they usually have a cardioid pattern. This makes them great for general purpose capture of audio but not great for targeted, intentional audio. Secondly, they are typically condenser microphones, which are very sensitive—again, great to make sure you don’t miss audio when you’re filming casually, but not great for audiophiles, given the positioning right next to the rest of your camera (which will introduce a high pitched whine to the track in addition to any handling noise you might accidentally add). Plus, quality will vary massively depending on distance of the subject from the camera.
Fortunately, it is not only possible to take your audio recording capabilities to a significantly higher level but less expensive and more simple than you probably think!
Crucial elements of excellent audio
- Always record at the highest quality setting possible
- Use the right microphone(s) for the situation
- Use the right recording method for the situation
- Minimize the distance between your microphone(s) and audio sources
- Minimize sounds added by your equipment (e.g. preamp hiss, camera whine, cable rustling…)
- Set levels carefully to avoid clipping without getting too-thin audio (aim for -12 dB)
- Be proactive to make syncing multiple sources of audio as easy as possible—record an internal reference track, use a clapperboard, etc.
- Use headphones to monitor the quality of your recording
Mic tech basics
There’s a lot to understand, especially if you’re just starting out in the world of audio recording, so make sure you have a handle on the following before disappearing down any other rabbit holes.
Types of microphones
There are a multitude of ways to capture an audio signal, but the three most common types of microphones are the following:
Dynamic microphones are some of the most common and inexpensive microphones. They record audio in much the same way as most speakers produce it: sound waves move a diaphragm containing a magnet or coil and the electromagnetic disruption produces the audio signal. This movement generates a small current so phantom power is not required, though they may also produce a quieter signal, thus requiring more amplification.
Condenser microphones generate audio signals by measuring changes in voltage as one plate of a capacitor is manipulated by sound waves. Power is required, whether from a battery or the device to which it is recording. Condenser microphones are extremely sensitive and can produce quite loud output.
Ribbon microphones are less common these days due to their fragility but produce a particular quality of sound which may be desirable. The movement of a sheer ribbon of electro-magnetic material between magnets generates the ribbon mic’s signal. It must not receive power, as it may damage the ribbon.
In addition to the type of microphone, you should also be aware of a microphone’s polar pattern, or the range of space in which it will gather sound. It is comparable to the field of view of a lens. While certain technologies may be predisposed toward certain patterns (e.g. ribbon microphones naturally tend toward a bidirectional pattern), the shape of the microphone is the main factor in determining how it will capture sound. Common polar patterns include:
• Cardioid: roughly the 180° centered around the direction the microphone is pointed. Your basic front-facing general-use pattern.
• Bidirectional/Figure 8: limited sensitivity to the left and right but high sensitivity to the fore and aft.
• Shotgun: a hyper-directional pattern used to eliminate as much background noise as possible when recording a specific source (e.g. a single person’s dialogue).
• Omnidirectional: the opposite of a shotgun pattern. 360° capture.
Yet another way to classify microphones is the way in which they are mounted. Consider the following:
• Handheld microphones are the stereotypical press microphone. They also need not be truly handheld: these microphones are easily mounted to tabletop tripods or swing arms to avoid handling noise.
• Lavalier or lapel microphones are designed to be clipped discreetly near a person’s throat or mouth to capture speech. “Lavs” are best paired with a wireless transmission system, but wired options are also usable.
• Camera-mounted microphones typically have cold-shoe mounts and plug into the cameras 3.5mm mic jack, though some (like the Sony ECM-B1M) connect directly through an accessory port in the shoe.
• Boom-mounted microphones are usually shotgun microphones found on the end of great big sticks that require a great deal more skill to operate than is generally assumed. Boom mic recording will give you the highest quality directional recording but will require a boom operator in addition to an audio recorder operator (on top of whoever’s running the camera).
Types of microphone connections
TRS connectors are commonly used in both consumer and professional settings. “TRS” stands for tip/ring/sleeve, referring to the three separate contact points on the jack (note the black separation rings). TRS connectors are most often found in two sizes: 1/4″ (like a guitar cable) and 1/8″ or 3.5mm (like what is commonly referred to as an aux cord). Be sure to use a balanced cable if you are using a TRS connector, as unbalanced cables are prone to interference.
XLR connectors are used almost exclusively on professional audio gear and offer a couple of advantages over TRS connectors. First, they offer a lock-in mechanism so you are unlikely to accidentally disturb the connection. (This is not always better, of course… the reason the aforementioned guitar cables use TRS connectors is because they are designed to be quickly and easily plugged and unplugged.) XLR cables also use completely separate wires for each of the three signals (positive, negative, and ground), providing a more effective grounding of the signal.
Ways to record audio for DSLR/ILC video
(NB: a preamp is something that amplifies an audio signal to a usable level for recording. Lower quality and/or overworked preamps will add undesirable noise.)
Internal recording using built-in preamps: Is recording good audio using the preamp built into your camera possible? Yes. As a general rule the mic input on your camera is much, much more usable than the built-in microphone. That being said, there are limitations. Internal preamps are more likely to introduce noise when you push them than dedicated audio devices, so you’ll want to record at the lowest possible levels. (Some microphones, like the Røde VideoMic Pro, feature built-in amplifiers to make this easier.) There may also be some limitations to recording quality depending on your camera. On the plus side, internally recorded audio is perfectly synced to your video. XLR adapters will allow you to use higher quality microphones with the 3.5mm TRS jack usually built into DSLRs/ILCs.
External recording (double-system recording): Using a separate recorder for your audio will give you the best quality audio in exchange for the most work. There are numerous dedicated audio recorders available—for what it’s worth, I personally use and love the Zoom H4n Pro, which also doubles as a USB audio interface—but they all share a few basic characteristics: quality preamps attached to multiple input channels, lossless recording options, independent level adjustment for each input, and none of the automatic adjustments made by many cameras’ internal systems (looking at you, Automatic Gain Control). Multitrack recorders (not the same as having multiple inputs) will even let you adjust the levels of each input after recording. The bad: using a dedicated audio recorder will usually require an additional operator, and you will have to sync your audio to your video in post-production.
Internal recording using external preamps: The “baby bear” option. Sometimes you won’t have the manpower to direct, operate your camera, and record audio separately. (Not to mention the fact that syncing audio can be a downright nightmare.) External preamps or “XLR boxes” like the Azden FMX-DSLR, Sony XLR-K3M, or Panasonic DMW-XLR1 allow you to run high-quality microphones through better preamps than those built in and mix input levels independently while still enjoying automatically-synced output. These boxes will also typically disable Automatic Gain Control, thank goodness. The downside is that, depending on the way the device is connected to your camera, you may still be running through the internal preamps. Be sure to keep the internal levels turned down as low as physically possible to avoid losing the advantages of the external preamps.
Further recommendations
A great place to start tuning your gear: open up the audio settings on your camera and disable all adjustments other than levels unless you understand the setting completely and are absolutely sure that it is helping your audio. That includes wind cuts, limiters, and so on. These settings are designed to provide better casual audio quality but will only make pro-level audio harder to achieve. There are better ways to achieve all of these effects, whether in post-production or by using a hardware solution.
The worst offender is Auto Gain Control, which is a sort of real-time compressor built into many cameras. Gain is automatically adjusted based on the level of noise detected, which sounds cool but in practice results in an irritating preamp hiss during quiet pauses, followed by excessively loud moments when sound returns and the camera has to lower the gain in response. Unfortunately, this “feature” is often not user-adjustable when recording in-camera—another reason to use dedicated peripherals.
Setting recording levels correctly is probably the easiest thing to mess up as well as the most important parameter over which you have control. If you are able, go into a pre-recording mode or make a test recording and watch your VU meter respond to the actual conditions you hope to record. (The VU or “volume unit” meter is represented by two lines that light up more with increased intensity of sound and is usually measured in terms of number of decibels below the maximum allowed by the recording device.) Any sound that goes over 0 on the VU meter will be clipped—a very unprofessional sounding effect!
As a rule of thumb, -12 dB is a good target for the bulk of your sound. At that level, your recording will have plenty of meat for your final mix, but there’s room for sudden loud noises. It’s understandable to worry that you won’t capture loud enough recordings, but remember this: it is fairly easy to amplify quiet audio in post-production, but it is impossible to rescue clipped audio.
Choosing the correct microphone and/or recording method can be tricky. There are plenty of products to choose from! If you would like specific guidance for your situation, feel free to leave a comment below, or call/visit a Mike’s Camera near you. We’ll be happy to advise you, and we love hearing about the creative projects happening in our communities!
Product highlight: the Røde Wireless GO II
Before closing this overview, I’d like to point out one of the newest and most exciting products in the DSLR/ILC audio market. The original Røde Wireless GO was already a pretty popular choice for independent filmmakers as a reasonably priced wireless lav-mic solution, but woah, buddy—this year’s version II is on a whole ‘nother level.
For under $300, you can record two (!) separate sources, either mixed together or discretely. Each transmitter can record up to 7 hours of lossless audio internally, either as a backup or as an on-the-go solution. The range in ideal conditions is almost three times that of version I (200m vs. 70m), so even in real-world usage you’re looking at an impressive distance. A respectable degree of fine-tuning control is accessible via clever use of the limited buttons on both the transmitters and the receiver, and full control is possible using Røde’s app. Robustly constructed (though not truly ruggedly), the clips on the back of each unit will fit into a camera shoe for quick mounting. To top it all off, while you’ll probably be using separate lav mics plugged into the transmitters’ 3.5mm TRS jacks, there are quite decent microphones built into each transmitter as well. The feature to price ratio on this kit is unbelievable, and I’d strongly recommend that anyone who is considering taking their filmmaking seriously also seriously consider this audio solution.
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