Home Recording Studio 101: How to Mix Audio

Audio mixing is the process of balancing and editing recorded audio tracks to produce a proper blend of all the sounds present on a single song. If you’re at the music mixing stage, it means you’ve already tracked your instruments—whether that’s drums, guitar, bass, keyboard, brass, strings, or vocals. And perhaps you’ve also created audio tracks using MIDI-controlled software synthesizers. No matter what instruments you’re using, mixing comes after tracking.

When you mix, you’re looking to do the following:

• Balance audio levels so that all instruments can be heard at their desired volumes. This can be assisted by compression plugins.
• Cover a wide range of frequencies so that the sonic palette sounds appropriately full. This can be enhanced with EQ effects and plugins.
• Add effects to dry audio tracks—including reverb, modulation, and distortion/overdrive.
• Remove mistakes that occurred during instrumental tracking—such as using AutoTune or de-essing on vocals, or using filters and EQ to cut the squeaking of guitar strings.

Audio mixing is very much a product of trial and error. Simply put, the more mixes you do, the more you’ll learn and the better your results will be. That said, here are a few tips to counteract a lot of common issues that home producers run into.

1. 1. Pan your instruments. Some beginning mixers make the mistake of placing all their instruments in the “center” of a stereo mix. Using subtle panning to push certain instruments to the left or right of a sound stage helps make each instrument distinct for the listener.
2. 2. Add compression, but don’t overdo it. Compression is a great tool for adding depth to your music and making your mixes fill the room. But overuse of this effect can deaden a mix. Remember that compression works by reducing the volume of your loudest signal and then (optionally) raising the overall volume of everything. This effectively makes you loud sounds quieter but your quiet sounds louder. If you use too much compression, you’ll lose any volume changes and make the music rather boring. So use enough to make sure everything can be heard, but not so much that you create a monolithic blob.
3. 3. Reverb is also great, but don’t let it muddy a mix. With today’s digital technology, it’s usually best to get a very dry, reverb-free recording of a vocal or instrument, and then add reverb during the mixing stage. This effect can be magical: creating the illusion of a beautiful spacious recording studio or concert hall when you were actually recording in a clothes closet. But much like compression, a little reverb can go a long way. This is particularly true of vocals. If your singer has a message to get across in her lyrics, don’t drown them out in a sea of muddy reverb. Add enough to create atmosphere, but not so much that you lose precision and definition.
4. 4. Use a high-pass filter, but once again, in moderation. Too much bass might sound cool in headphones, but it can muddy up a mix and make it hard to hear individual parts. Subtly applying a high-pass filter, which cuts certain low frequencies and allows higher ones to pass through, can bring clarity to your mix. Most EQ effects and plugins have a high-pass filter option built in.
5. 5. Test your mix on multiple sets of speakers. If you’re mixing while using high-end headphones or studio monitors, that’s great in terms of your ability to add nuance and detail. The problem is that a lot of your listeners may not be playing back the track on such nice equipment. Think realistically about how most of your audience will be encountering this music. Will it be on laptop speakers? A car stereo? Earbuds? A TV soundbar? Make sure you’re listening to your mix on the medium by which it’s likely to be heard.

Mastering is the final stage of the recording process. Unlike mixing, where an audio engineer tweaks each instrumental track comprising a single song, mastering involves working with a finished mix. Usually, this means a two-channel stereo track (a left channel and a right channel), but for home theater mixes, the finished product might have six to eight tracks to account for things like subwoofers and surround speakers.

Mastering engineers typically add subtle amounts of compression, limiting, and EQ to make a final mix consistent with the standards of today’s radio, television, film, and streaming standards. Typically this means that they’ll make the track as loud as possible without undermining the nuance of the original engineer’s mix.

Armin van Buuren, a dance music DJ, record producer, remixer, and label owner from the Netherlands, has the following insights on the mixing and mastering process:

1. 1. Mixing and mastering are all about making creative choices to highlight different elements in your track. Using EQ and volume control, you’re trying to make sure the audience is hearing the most important parts of your recording.
2. 2. It’s better to let your tracks sit a day or two before you mix and master them. Things always sound different when you’re listening with fresh ears. When you do sit down to review and mix your tracks, test your mixes on multiple sound systems—in your car, in a friend’s studio—to make sure they have the same sound quality in any environment.
3. 3. Consider giving each track its own EQ setting, and note that changing the reverb, release, or attack on each track can make a difference in the overall sound. Reverb is essential to trance music and creating a dancing atmosphere, but it can clog your mix without proper EQing. A reverb plug-in that lets you adjust the frequency spectrum of the reverberations, like the ArtsAcoustic, can help you avoid this issue.
4. 4. When it comes to mixing vocals, it’s important to listen back to your composite vocal on its own, without any effects processing or any music behind it. You should listen carefully for imperfections, any background noises, strange mouth sounds or clicks, pitch inaccuracies, etc. If you or your vocalist are unhappy with your composite, ask your artist to do more takes. Once you are satisfied, you can begin to clean up the track.
5. 5. When you edit a vocal, leave some breath in to give it a natural sound, but take out any noisy breathing that might distract from the music. Consider using a de-esser plug-in to reduce the sharpness of harsh sounds like “s,” while taking care not to lose important parts of the singer’s words.
6. 6. Record all of your lead vocals at the same time to avoid changes in the sonic quality of the vocal, due to the food the artist has eaten (such as milk), sickness, or strain on the vocal cords. If you’re not getting the best performance out of your vocalist, play around with what the singer’s hearing in their headphones by adding reverb to their voice or playing a different backing mix. The goal is to get the vocalist excited and encouraged to make the next take their best.
7. 7. Consider using multiband compression to bring the track’s loudness up across the frequency spectrum; use a limiter to get the overall track as loud as you can without distorting.
8. 8. As part of the mastering process, try to constantly A/B your processed mix against your unprocessed mix to hear how the sound has changed. To make this easier, have the two mixes set up on auxiliary channel strips that get their signal from the pre-dynamics bus. When tweaking the processed mix, be careful to make sure the perceived volume is the same as that of the unprocessed mix—otherwise your ears will be fooled into preferring whichever is louder.
9. 9. When testing your final mix, turn things way down—if you can hear all the important elements at a low volume, chances are your mix is well-balanced.

Learn more about audio mixing in Armin van Buuren’s MasterClass.

The popular Canadian producer and composer Joel Zimmerman, otherwise known as deadmau5, has the following tips about mixing in the context of EDM.

1. 1. The mixing process starts as you’re laying down your first tracks. Set up groups to help you keep organized, with the drums all summing into a drum group and the bass and synth pads each doing the same.
2. 2. Balance your track volumes against each other roughly, and try to keep your master volume around -6 DB so you have headroom to work with when you go into your mastering plug-ins later.
3. 3. Use EQs to help similar instruments or instruments that play in similar ranges fit together without sounding muddy or dull. Figure out what part of the harmonic spectrum you want from a given instrument—top-end shimmer, or bass resonance for instance—and duck the rest of the frequencies to make sonic room for other sounds.
4. 4. Use side-chain compression, keyed to your kick drum, to make big leads feel like they’re a cohesive part of your track. This ducks the lead’s volume every time the kick hits and keeps it from sounding like it’s sitting awkwardly on top of the mix.
5. 5. You also want to duck your bass volume when your kick drums hit, to avoid phase-cancellation dulling your kick sound. An LFO tool works even better than side-chain compression for this.
6. 6. Most importantly, don’t feel like you need better gear to be better at mixing. DAWs like Ableton come with all the plug-ins you really need to make a great sounding mix. Focus on training your ears and getting used to what the plug-ins can do for you before you start investing in more studio equipment.

Learn more about digital music production in deadmau5’s MasterClass.