by Bob Kirschner, Chief Engineer at CMD
I thought I’d share some general thoughts about what goes into mixing audio for post production projects. Here at CMD we take on audio interns regularly and I provide significant training. I’ve found that interns who attend audio programs typically get good education in the fundamentals, and sometimes also in an area of focus such as sound design or music production. But mixing is an area that interns find challenging and even a bit scary. Probably because it requires being confident in the fundamentals and having the ability to use your ears properly, a combination that comes with advanced knowledge, dedication and practice.
How To Achieve A Great Mix
Mixing sound for an audio post project is always challenging. The good news is, the skills needed to achieve a great mix can definitely be learned. But like most high-level skills, it requires practice to get to the point where you can accomplish the perfect mix (or if not perfect, than achieving a level where you know that your mix sounds great on many different speakers).
A good mixer has a keen ear for many things, including tone, volume, balance, and depth. Mixing audio requires the power of serious concentration and takes immense patience. Most importantly, you need the ability to adjust the sonic details while understanding the effects on the big picture - not an easy thing to do!
For example, you’re working on a spot and the music track is arranged nicely for piano, strings and guitars. But when you balance the track in with your dialog, why does your dialog get lost? The problem is, the frequencies of the music are directly competing with the frequencies of the dialog. What you don’t want to do is brighten up the dialog too much - you might end up with sibilant, harsh-sounding dialog. The better approach is first reduce the mid-range and upper mids of the music with EQ and/or narrow-band compression. This will go a long way to help the dialog stand out. Be sure make these adjustments while you’re listening to the entire mix in context.
In post production, the most important thing to keep in mind is: dialog is king. I’m not suggesting to just mix dialog loud and that’s that. Actually, this is a common problem - mix the dialog too loud and the quieter moments of music and sound effects will get lost. A good approach is to treat dialog with the highest priority. Dialog is the element that, to the greatest degree, carries the message directly to the listener. Of course, music and sound effects have a huge impact. But getting dialog to sound great will do the most to ensure the success of your mix - and will definitely make your client happy!
Some Tips For Mixing
In almost all cases, establish dialog levels first. This provides the anchor for all the other the elements to join in and around.
Use a fader, not a mouse! Mixing is the art of balancing audio to make it sound good to your ear. There are so many reasons why working with a fader is essential. For one, and this is a huge one, it lets you use your ears. You can mix with a fader (using automation) and not have to look at your screen while clicking with a mouse. This lets you concentrate on using your ears to set levels. Of course you’ll still be looking at your screen but you’ll be able to focus your ears on deciding what sounds right.
Use multiple speakers for mixing. High quality, full-range speakers are needed for critical listening. But be sure to also use smaller computer-style speakers for checking balances. Headphones are great for checking your mix, particularly if the format is primarily for headphone playback (podcast or audiobook).
Get accustomed to mixing at a specific SPL level. I listen at 78dB for television broadcast, and 68dB for digital. Once your ears know how loud something feels (sound pressure) it makes it much easier to mix with confidence.
