While I'd be the first to admit that my sound engineering skills are somewhat rudimentary, there are a number of helpful techniques I've learned along the way for mixing in a software environment. Many of these may be obvious to more experienced producers but not necessarily to us hobbyists, and I wanted to share some of my findings.
We recently completed the final mixing stage of the debut Pinscape full-length album - with production and mixing assistance from Scott Worley of Jatun - and it was a daunting yet enlightening process. In preparation for getting the songs sent to Taylor Deupree for mastering we went through many mixing revisions (the final version was labeled "mixdown 5.7"); below are some of the most beneficial tips I learned and used throughout this process.
1. Attenuate all channels to allow headroom on the master output
I tend to mix things too hot in the early stages of recording a song, and find that I often need to reduce channel volume when refining the mix. If you use as much volume automation as I do, this can be a little tricky. Cubase curiously does not include a simple utility/gain plugin for adjusting channel volume post-inserts/EQ, so I had to get creative and use the gain knob in the native channel-strip's Expander. This allowed me to attenuate by 6dB and then copy and paste the same Expander settings to all necessary channels in the project, resulting in a mix that no longer entered the red zone on the master output. Similar tools in other DAWs - such as Ableton Live's Utility effect - will let you accomplish the same thing.
2. Double up a sub bass line to bring out melodic content
Bass tends to be my biggest challenge in a mix, and I think this technique really saved me on this most recent project. Noting that many of the triangle wave-based synth bass lines in our songs were inaudible on smaller speaker systems, Scott suggested that we duplicate the channel and adjust to bring out more midrange melodic content. On the duplicated channel, this typically involved some combination of rolling off the low frequencies, boosting the low-mids, adding a bit of tube-style saturation to bring out harmonics, and even changing the synth's oscillators to a richer sawtooth-style sound. Adjusting this low-to-midrange-focused channel to taste next to the original bass channel allowed us to get the best of both worlds with deep, rumbling sub bass that won't get lost amongst other melodic elements even on the lowliest of laptop speakers. A similar technique could also be applied to kick drums.
3. Bounce MIDI tracks and certain automation to audio
This one may boil down to personal preference and difference in workflow, but we ended up having to commit a lot of channels to audio to fix issues found late into the mixing process. For instance, I rely heavily on MIDI Program Changes to control Native Instruments Maschine drum pattern changes, but ran into some odd timing issues during song export; bouncing the drum channel to audio before export took care of this. Similarly, we encountered some weird audio blips with an automated comb filter effect, specifically when it was brought out of its Bypass state. Bouncing this to audio and trimming the offending blips was the quickest and easiest solution in the moment. Beyond just fixing strange anomalies such as these, working in the audio realm allowed us to get creative with certain sounds, easily reversing, time stretching and stuttering various parts to add that final touch before mastering.
4. Roll off unnecessary frequencies with EQ
A common technique is to try and carve out a frequency space for each and every instrument. Rolling off unnecessary high or low end frequencies for each channel is an easy way to open up a mix, while notching out a specific frequency range from a channel that may be conflicting with another will allow them to sit well together. This can result in some strangely-thin sounding parts, but when played back in the mix every element will have its place and sound appropriate. The real-time spectrum analyzer built into the EQ view on every Cubase channel makes it easy to see the effect of these frequency adjustments. I watch it closely as I go along but try to remember to ultimately trust my ears more than my eyes.
5. Don't forget about panning
I often use panning for creative effects like a reversed cymbal crash traveling from one ear to the other as a dramatic build-up to the chorus, but sometimes forget to use it more traditionally. Don't be afraid to pan that guitar part nearly hard-left for the entirety of a song, as long as there are other elements panned to the right to balance things out. Spreading parts across the stereo field can really open up an otherwise dull-sounding mix.
6. Trim audio events to eliminate unwanted noise
For any parts recorded via microphone (especially a sensitive condenser), you will likely want to trim the audio to eliminate elements such as breathing, headphone bleed, and ambient noise. Some people may prefer to leave things like the inhale before a vocal part, but I tend to trim them pretty closely with a short volume fade on each end. Do the same for large gaps of silence between parts during a take and use a noise gate to silence some of the shorter spaces. This tip can vary based on personal preference, but the point is to ensure you don't end up with unintentional noise buried in your mix that may not be noticed until it's too late. I unearthed a bothersome lip-smacking sound on a vocal take pretty late into the game after repeated headphone listens and was very happy to eliminate it before being released in the wild.
7. Have a quick and easy way to A/B across different speaker sets
I use the Mackie Big Knob to effortlessly switch between my primary Event TR8 monitors, some average Logitech computer speakers with subwoofer, and a very small set of cheap Dell computer speakers. This gives me a good reference point with the monitors, and a quick way to see how the mix may sound on more typical listener setups. Referencing with a few pairs of headphones is also a must so I keep both my AKG Q 701 and Sennheiser HD 202 sets plugged into my audio interface at all times. And don't forget to review your mix in the car, on cheap earbuds, from across the room with your TV/media setup, etc. Listening from so many sources can be tiresome, but worth it in the end.
8. Keep a list of what you've changed, and what you need to change
After all the referencing you've done in step 7, you ought to have a good way to keep notes and a to-do list going so you don't get lost. I use OneNote to keep track of my mixing to-do's but there are endless tools for the job, ranging from Trello to Evernote to Wunderlist to, of course, the classic pen and pad of paper. The point is to keep tabs on what you'd like to change as you repeatedly review your mixes, while also keeping a history of the changes you've made along the way. That second point not only helps to see the progress you've made and feel good about it, but also allows you to share this with your bandmates and anyone else involved in the production.
9. Use a compressor with wet/dry functionality on group channels
Compressors are powerful tools that can be used for everything from the popular side-chained pumping effects heard all over the place to simply leveling out the dynamics of a vocal performance. I use them for many things and have recently found a more subtle approach which requires that the compressor include a wet/dry or mix parameter (this is not as common as it should be from what I've seen). The Cubase 7 Tube Compressor plugin offers this and it allows for a great balance of the squashed compression effect that can make drums or other elements sound bigger than life along with the natural dynamics that make these things sound human. I use this 50/50 mix often on group channels with several drum channels routed into it, and this blend of compression really helps to glue the elements together without taking the life out of them.
10. Save multiple versions of project files
While this last tip leans on the administrative side of audio work, it is nevertheless an important one when working towards the finish line. This is somewhat related to the idea of keeping notes on the adjustments you've made along the way and it ensures you have a fallback plan if things go awry with your latest project file. Perhaps you made a mistake and hit the Save button before realizing your Delete key had wiped out an entire channel or a batch of intricate volume automation. Maybe you just want to go back to a previous version for reference because things are no longer sounding as good as you'd like with the current mix. Just do it: any time you make a significant change or a number of smaller changes to your project remember to Save As and give it a new name. I tend to append version numbers onto my files like "Song Name 2.5", if the song has gone through 2 major revisions and 5 smaller ones. Choose a naming convention that works for you, and don't forget about proper on-site AND off-site backup of all this data!
Hopefully a few of these suggestions help you in your journeys to craft the perfect mix. There are many more advanced methods to learn out there, and it can be a job in and of itself to find and implement the ones that make sense for your workflow and desired sound. Don't forget the more obvious things like taking breaks during work sessions to rest your ears, as all the tricks in the world will be of no use if you can't attentively listen to what you're doing.
What techniques do you employ to get your mixes ready for the world?