When you move into some serious sound editing, you just might need more robust audio tools than your camcorder and editing software supply. Welcome to the realm of mixer and audio editing software from a pro in the know.
Audio editing software has more fine-tuning tricks than most video editing programs offer, and mixers come in all shapes, sizes and price ranges. But they all do one thing: combine multiple audio inputs for recording. First, let’s talk about mixers.
Some are as simple as a two-input field mixer, while others may sport dozens of channels with hundreds of knobs and buttons for the ultimate in control. Regardless, if you’re in the market for a mixer, it helps to have a clear idea of what you need your box to do. For the next few minutes, let’s take a look at audio mixer features and how they can deliver convenience, flexibility and audio clarity for your productions.
We have Greg Mackie to thank for the current state of the mixer art. His 1991 release of the CR-1604 turned the humdrum mixer world on its ear, clearly demonstrating that quality and convenience could be built into a durable, affordable product. Ever since that landmark, manufacturers have emulated Mackie’s simplicity and function, creating a huge market of small inexpensive mixers. Microphone preamps, in particular, have benefited from the revolution. Now everyone can afford good-quality mic preamps. Design specifications that seemed esoteric just 20 years ago are now common in virtually every make and model. For the video producer, this means it’s hard to go wrong when it’s your turn to make a mixer purchase.
Your Needs, Please
It’s easy to get lost in all the facts and figures surrounding a mixer purchase, so let’s start with what you need. How many mic inputs do you really need? Will you ever use condenser microphones that require phantom power? How many mono or stereo inputs could you use on a regular basis, and what about connector types? Will you need battery power for portable use? How will you integrate the mixer in your production chain? That’s a lot of questions, but you should have answers before buying a mixer you’ll hate for years to come.
Inputs and outputs are easy – just do an inventory of your existing equipment and connectors. Consider what other gear you may buy or upgrade in the near future, and check the requirements. Professional XLR connectors are standard for microphone inputs, and 1/4″ connectors are standard for line-level sources. Outputs may be on XLR, 1/4″ or even RCA connectors. If the mixer you’re considering isn’t a perfect fit for everything you own, a few inexpensive audio adapters may solve the problem. A related issue is output level. If your mixer has line-level outputs on XLR connectors, and your camera uses a 1/8″ stereo mic input, you have a serious mismatch. Yes, there are adapters for this challenge too, but some of them cost as much as a mixer. It’s better to get closer to your actual needs first. Fortunately, there are plenty of options.
Aside from the technical aspects, there are functional concerns. For instance, do you need to mix multiple sources in the field? If so, a battery-powered option is a consideration. How much real estate is available in your studio or edit suite? A 32-input model might be perfect for mixing a rock band or a musical, but it’s tough to find three or four extra feet of space on your computer desk.
Knobs and Buttons
Most modern mixers offer a variety of controls to help match, shape and route the input signals. A gain or trim knob allows you to adjust the volume (gain) of each incoming signal to better match the others. This is perfect for blending multiple interview microphones, musical instruments or media players. Tone controls come in several flavors. A simple two-band version offers basic bass and treble controls that are fine for basic adjustments. A three-band equalizer adds a midrange control, increasing your options. More complex mixers may offer sweepable midrange frequencies, dual midrange controls or a full parametric equalization section. Don’t let the extra knobs scare you off; they all adjust the tone of your signals. You may also find a low-cut switch on some mixers. This is a simple form of tone control that eliminates the lowest of frequencies – perfect for minimizing wind or mechanical noises.
The final output of your mixer could be as simple as a mono or stereo output with a volume control. You may also find routing buttons that allow you to send various signals to alternate output jacks. This makes it easy to send one or more inputs to a secondary mix for a house sound system, audio-only recorder or headphone cue feed. Although not mandatory, it’s nice to have level meters on your mixer. This lets you check incoming and outgoing signals for optimum volume. Even a simple 5-segment LED meter is better than nothing, though as you grow into the world of audio, you’ll be wanting more.
As you know, the world is converting to digital, and the audio mixer segment is no exception. Many manufacturers offer digital mixers, although most models will severely tax your budget. There are exceptions, though, and digital mixers tend to offer a lot of bells and whistles. Don’t forget, you already have a simple digital mixer inside your computer. In a pinch, it’s easy to blend a microphone, CD audio and a media player with no external hardware. It’s also very easy to route the resulting mix to your digital audio software for further processing.
It’s All Up to You
The choice of an audio mixer is a subjective decision. A mixer that’s perfect for me may not suit your needs at all. Each manufacturer has a unique approach to mixer design, which results in a wide variety of mixer sounds and feels. The American mixers are different from the Japanese versions, while the European offerings differ from their Chinese cousins. Your job is to research your specific needs and compare them to the features and prices on the market. Whenever possible, get your hands on the potential candidates and test them with a microphone or other sound source. Plug in some headphones and check the tone controls, sliders and other controls. Look for sturdy construction, responsive adjustments, ease of use and flexibility. Should you find everything in a package that fits your budget, grab it and run. You’ve just made a significant investment in the quality of your productions.
With all this talk of hardware mixers, it’s easy to forget that some of the coolest mixers in the world are virtual. Some level of software mixing is included with all multitrack recording packages. It may be as simple as a volume and pan control or more elaborate than any hardware mixer you can imagine.
Most often used in post production, software mixing offers you several advantages. First, all your mix moves and channel settings are saved with the project. Everything comes back up exactly as you left it – whether it was yesterday or a month ago. In addition, most software mixing allows you to use plug-ins – little bits of code that emulate real devices like EQ, compressors, reverbs and even guitar amplifiers. Using plug-ins gives you a virtual rack of audio equipment that would cost thousands in the real world. Finally, once the signal is in your computer, all the processing takes place in the digital domain, giving you clean mixes and the ultimate in control.
Contributing Editor Hal Robertson’s first audio mixer was an ancient Shure M67. He’s upgraded a couple of times since then.
Side Bar: Virtual Mixers: Limitless Possibilities Abound
Audio editing software, also known as a Digital Audio Workstation, is to audio what your NLE is to video. With a DAW, you can trim and splice audio, tighten narration and even out differences in volume. With signal processing, it’s easy to transform the tone quality of a piece, making it fuller or thinner, or creating the illusion of an acoustic environment. You can even do pitch and speed adjustments, making your voice sound like Darth Vader or stretching a short piece to fit a specific time limit. Having and understanding a solid audio editor are essential for the video producer today.
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