Choosing a mixing engineer is a key part of producing a song. A good mix can help a good recording shine, while a mediocre mix might make it sound flat. Since it's not common practice or recommended to record or re-record parts after a song has been mixed (although in rare cases it happens), mixing is undeniably a milestone in the production process. It's a point of no return. As a result it's where musicians and producers have to 'let go' and put their faith in a specialist to do their recording justice. Lets start from the top.

Music mixing is the process of taking a multi track recording and 'mixing' it down to one single stereo track (left and right). Before mixing you have a multi track session – for example 12 individual drum tracks, 6 vocal tracks, a bass track, 2 guitar tracks, 4 keyboard tracks totaling a few dozen tracks. After mixing you would have one stereo file. This audio file is almost the final product for distribution. A song is truly 'done' once the mix is mastered. So why is mixing so important? Because of what happens during the mixing process. A mixing engineer does much more than just 'combine' the tracks. You see mixing is all about context, the way individual elements of the arrangement behave, sound and feel relative to each other, and how that affects the overall experience of the listener. The mixing process can be divided into the following main parts. An easy way to understand them is through the tools the mixer uses for each. The combination of these things the mixer does hugely affects the sound and feel of the recorded song, which is why good mixing is so important.

Balance and panning

One of the most important components of mixing is balancing the levels of the individual instruments relative to each other. Should the guitar be loud or soft? Which instrument takes center stage at which section in the song? Balancing the levels of the individual recorded instruments might sound easy, but it's an art form. It's also dynamic. The level (volume) of a track (such as an instrument or voice track) does not stay level throughout the song. Different instruments typically take center stage at different moments otherwise the song would be boring. And because most instruments are dynamic themselves, some leveling is necessary to ensure that they are heard even if they sound too soft or loud in certain parts relative to other instruments. Sometimes an engineer will also 'mute' (silence) specific instruments in different sections of the song, but typically this is done as part of the arrangement by an arranger or producer before the tracks are given to the mixing engineer.

Panning involves choosing where on the stereo spectrum tracks play. Since most music today is listened in stereo, individual instruments can be placed on the far left, smack in the middle, far right, or somewhere in between. Panning is used creatively, to create a feeling of width and sometimes motion. It's also used surgically, to help the listener understand which instrument is taking 'center stage' (literally).

Equalizing and compression

After level and panning, two important tools in a mixer's toolbox (and on most mixing console channels) are equalization and compression. If you are not familiar with what equalization does, just think of the 'treble or bass' knobs on old stereos or the EQ tab in iTunes. EQ is used to manipulate (raise or lower) certain frequencies. Sometimes EQs are used to manipulate groups of instruments or even the whole mix. The frequency curve an instrument was recorded depends on how and where it was recorded and with what microphone (if it's a live instrument), and it doesn't necessarily sound the best it can, especially in context of all the other instruments around it. Engineers can make instruments brighter or darker, more bass heavy or thinner in very particular ways to make them sit better with other instruments and make sure they all have room in the mix. Equalization is used to treat instruments that fight each other for 'space' in the frequency spectrum, for example bass and kick drums, which share low frequencies that sometimes compete. They both may sound great on their own, but together sound muddy. EQing can be used to bring out the best of a track or hide problem frequencies in specific tracks. To make instruments poke out of the mix or to feel softer, to get more clarity or increase or decrease the perceived warmth or weight of a track.

Compression is used in two ways. The most common use for a compressor is to level individual tracks' dynamic range. Imagine a waveform that has big spikes and deep valleys and ironing it out, so the soft parts become bit louder and the loud parts become a bit softer. A good example is the human voice - a very dynamic instrument. Within sentences or even single words there are big volume changes. Since we listen to pop music on small speakers or ear buds, often in noisy environments, hearing all the nuances of dynamic instruments is difficult, especially if we hear them alongside a dozen other instruments. Compression helps. It enables the listener to understand every soft syllable of a singer's voice, while ensuring loud syllables don't poke out to be harsh. This is key for being able to enjoy a recording without having your hand on the volume knob, as well as for understanding all the lyrics even in the context of a busy mix and a noisy environment. Compressors are used to 'squish' and flatten out the roller coaster that is the internal volume of these tracks.

The second way compressors are used is as a creative affect. A really cool thing can happen when you exaggerate a compressor's effect and push it hard. It actually changes the feel of the instrument. It can make an instrument that sounded kind of wimpy feel strong or more urgent. It can literally make drums sound like they were hit harder than they actually were, or vocals sound like they have more urgency and pop than their original recording. Compressors can be also used to make certain instruments feel like they are 'pumping' if used in a certain way and to 'glue' certain instruments together if they feel disconnected. Compressors are magical sonic manipulation tools, and when used correctly, can add character. This is why engineers love them so much.

Creative effects – reverbs, delays and more

A mix engineer's arsenal includes other creative effects for making songs sound more interesting and add 'ear candy'. Reverbs, delays, distortion, filters, chorus, flangers are all popular creative effects. Reverbs and delays are probably the most popular of the bunch and are used to add space and depth to mixes. Adding reverb or delay to instruments makes them sound like they are in a physical space. Since most tracks these days are recorded with the microphone very close to the source, they end up sounding up very close and dry when played back. Reverbs and delays address this problem and psychoacoustically place that same dry recording in a lush space. There are different flavors of reverbs and some actually have names of spaces like 'small club' or 'large hall'. By adding reverb and delay tracks sound 'farther away', providing an awesome way to give the mix depth. Keeping certain instruments 'close' (dry) and others 'far' (wet), creates an illusion of space between them. Too much or the wrong type of reverb or delay will quickly make a mix sound cheesy or amateurish. When used well, they can be beautiful and moving. You can use short and minimal reverbs for an intimate sound, or big ones for a dreamy or stadium effect. Reverbs and delays are sometimes used to soften particular tracks that otherwise sound harsh and dry, and other times to glue instruments together and make them sound like they were recorded in the same room when they were not. Some popular uses for delay include slap delays (think Elvis or John Lennon vocals) or echo repeats synched to the song rhythm (as you can hear in many pop productions). These echoes can be made to sound washy or well defined.

Mixing is about skill, taste and knowing to serve the song. The same song can be mixed in many different ways. Mixing entails many creative decisions and skilled 'moves' and when done well it can truly make a song shine and be interesting.

There are many mixing engineers out there with varying styles, experience, expertise and levels of customer service. Here are questions to ask and things to look for that will help you make a decision about whether a mixing engineer is the right partner for you.

Mix Samples

There is nothing more helpful to understanding an engineer's style and skill than listening to previous songs they've mixed. A sound sample can speak a thousand words and you should trust your ears. One thing to keep in mind is the tracks they worked on might be different than yours in style or recording quality and that can make a big difference. It's fair to ask an engineer if you can expect similar results after you discuss price and send them a rough mix or your tracks. At that point they should have enough information to tell you if you can expect your mix to be in the ballpark of the samples in their reel.

Genre

Every engineer has a different mixing style, and that's natural. This is no different than musicians who are more connected with and (have more experience in) a particular genre. A mixing engineer's style will often depend on what music they like, what they work on most often and their abilities. Really 'getting' the nuances of a any genre is key to nailing that sound. There are engineers who are eclectic and work on a wide range of genres, but finding a specialist is often helpful. I recommend listening to an engineer's reel to get an idea of what their style is. If an engineer really connects with your genre of music, that will make a huge difference. Mixing engineers are geeks and if for example they like EDM and work on a lot of EDM, they will already know how to get that pumping sound you might be looking for and won't have to start experimenting. The approach for EQing a kick drum or bass for a Jazz track is totally different than for a rock song. If you don't hear a track in your genre in the mixer's reel you can always ask if they have one that wasn't included.

Budget

This one is obvious. Mixing engineers work with a wide range of budgets, like everything else in life. Don't approach a Grammy winning engineer if your budget is $400 per song (hint – the top ones charge thousands per song). In the same vein, don't expect your mix to sound just like Katy Perry's if you recorded the song in your bedroom and have $200 per song for your mixing engineer. There are young passionate engineers who will work all night for you for $200 and might get you a significantly better result than what you can get yourself. Be realistic about what you're willing to spend and what you're expecting in return. In general rates start at $200/song and go up to several thousands per song. You start having access to very experienced engineers at around $500 per song. Tip - Some engineers will cut you a deal on the per song rate if you pay for multiple songs in advance. Some of the things that determine an engineer's going rate are their years in the business, their credits (this is a big one), reviews, their skills, their gear and their availability.

Payment terms

Some mix engineers want payment upfront, some half upfront and half on delivery and others are willing to receive full payment on delivery and only when you are happy as long as you fund the job to SoundBetter (so they know you won't just disappear). You can choose what you feel more comfortable with; just make sure you understand what payment term a proposal includes before you choose your engineer. If you really want to work with someone but you don't feel comfortable with their payment term, you can ask them to change it and they might agree. Be fair and sensitive to the engineer's time spent on your music.

Credits and Reviews

World-class engineers rely on their credits to speak for their ability. If you've heard songs they've mixed on the radio you know the level of skill you can expect from them.
For engineers with fewer or lesser-known credits, reviews are a powerful alternative. By reading what other clients have to say about working with them, you'll get an idea of whether they delivered on the clients' expectations. All musicians are emotionally attached to their music. If numerous musicians gave a mixing engineer a great review, you know that not only the engineer delivered on expectations, but they likely also gave good customer service. Finding an engineer that will take the time to realize your vision is important. An engineer might have skills, but if they aren't open to accommodating your feedback you run the risk of having an unpleasant experience or not getting a mix you are happy with. You can read reviews for engineers on SoundBetter. Verified reviews are ones who's authenticity we guarantee. By hiring someone through a platform like SoundBetter you have some extra leverage because you will give the engineer a review at the end of the work, and they know that. This helps ensure they go the extra mile to make you happy.

Gear

The gear an engineer uses is less important than the other things above. There are awesome sounding radio mixes that were done all 'in the box' (i.e. mixed in the computer as opposed to on an analogue mixing console). A great mixer can do wonders on a laptop and a mediocre or wrong mixer for the genre can butcher a song on an analog console. Don't believe the hype. Nonetheless, it's worth looking at where an engineer works and what gear they use. It's just one more factor in understanding how serious they are about their trade. Are they in an acoustically un-treated bedroom with a laptop and mediocre speakers, or are they going to mix your music on a professional console in an acoustically treated control room? Most engineers these days fall somewhere in between on that spectrum. I wouldn't make gear the deciding factor, but I do recommend taking note.