So you’re wondering if perhaps there are some things you can do to your mixdown environment that will improve your sonic outcomes. Here are some tips that won’t kill the bank balance.
Using headphones
Let’s first look at the pros and cons of mixing with cans. The clear advantage headphones have is that they eliminate room acoustics from the picture. If your mixdown room is less than ideal, this can make it a very substantial advantage over external monitors. There are other advantages too. Together with a laptop, you can take your mixdown session into all sorts of places. With fully enclosed headphoness you don’t have to worry about disturbing others in your environment and equally you can stop the sound of your environment from distracting your focus from the job at hand.
Ideally you’d want to have a good pair of headphones that provide you with an accurate rendering of the mixdown you’re creating so that you produce a mix that translates well to other listening environments. As with all sound mixing environments, you want them to be revealing and not flattering so you can make informed judgements.
Comfort is an important consideration too. If you are going to be spending some time in those cans, and a mixdown can chew through quite a few hours, use headphones that don’t make you feel like your head is in a vice after a short while. The best ones sit around your ears, not on them.
Where headphones tend to fall down in comparison to external monitors is rendering the stage field accurately (where instruments appear to be placed in 3 dimensions.) A common experience when mixing in headphones is the feeling the band is in your head. Consequently, it is harder to make judgements about where instruments sit in the mix. It’s also harder to judge when you are over doing reverbs.
I’ve heard engineers describe the experience of mixing in headphones like using a microscope – you can hear detail better, but the image is somewhat distorted. Many engineers use headphones as a secondary reference to their main monitors to help enlighten them about how their mix is travelling.
Cost is important factor too. Good quality headphones are generally a fraction of the cost of good quality monitors. Bang for buck, headphones win hands down.
Mixing with near field monitors
There are good reasons why using near-field monitoring for mixdowns (1-2 metres from ear) is so popular amongst engineers across the world.
The further away your monitors are, the more the room acoustics come into play. If your room acoustics are less than ideal, why not reduce the impact of the room and go nearfield. The downside is the sweet spot is narrowed and you can find yourself doing bobblehead moves to stay in that sweet spot. Which brings me to another tip – mix in mono! You’ll hear phase incompatibility issues more easily and you’ll make better judgements about where to sit instruments in the mix compared with stereo, while also reducing bobblehead syndrome. Leave the positioning in stereo to the very end of your mix session.
Nearfield monitors tend to be small, which means they don’t do well reproducing lows. This can be used to your advantage, however! Most listening environments out in the world are bass challenged, so mixing with little sub bass representation helps ensure you get the midrange tones balanced for instruments like the bass.
In the eighties NS10s became ubiquitous in top studios around the world because they produced mixes that translated well into the big wide world. Roxy music’s, “Avalon”, Bruce Springsteen’s, “Born in the USA” and David Bowie’s, “Let’s Dance” were all mixed on NS10 monitors. I sold mine and I regret it.
Placement of your monitors
Position such that the two speakers and your head are positioned to form an equilateral triangle – that is, the distance between each speaker and the distance from each speaker to your head is the same. Now close your eyes and listen to some reference music. Note the position of instruments in the stage field. Now move closer to the speakers and reassess the stage field. Notice it is now wider, but also more distorted. If you move further back the stage field will narrow. Now try shifting the speaker positions slightly. With your eyes closed find the sweet spot where the stage field feels the most convincing for you. Experiment with this approach until you find the what works best for you.
The best listening position for mixdown is at the apex of the equilateral triangle formed between the two monitors and you the listener.
Assess the influence of your reflection points
Where are your reflection points? Look around you. Where are the nearest points where the sound is reflecting back to your ears? Why is this a problem? The reflected sound will arrive at your ears later than the direct sound from the speakers, and this time shift creates a hollow sound effect known as comb filtering. This is not a desirable sound for mixing.
If you haven’t heard comb filtering before, there’s an easy way to learn what it sounds like. Put a speaker on one end of a table and at the other end, while listening to some music from that speaker, slowly crouch down until your ears are level with the table top. As you do this you’ll hear a rising tone as your head approaches the height of the table. Likewise, if you start at table height and stand up-right you’ll hear a dropping tone. Now that you’ve heard this, stop in a position and note that the phasey sound freezes in tone. Remove the table and listen again in that same location. That comb filtered sound should now have disappeared.
What’s going on here?
When you are close to the table top, the reflected sound off the table top arrives shortly after the direct sound from the speaker, so you are hearing an echo. The thing with echoes is that if they are less than about 25 ms later than the direct sound our brain doesn’t hear it as a discrete echo, rather we hear it as one sound – a comb filtered sound. When our ears are close to the table top the reflected sound is arriving at our ears less than 1 ms later than the direct sound. At these time shifts it’s only the higher frequencies that are affected, hence we hear this as a high hissing type of sound.
When we move our ears higher and further away from the table top, more and more lower frequencies are comb filtered and the comb filter sound becomes more broadband. Also the sound pressure level of the reflection is reduced in comparison with the direct sound, so the affect is not as noticeable. In general, the further away your reflection points are from your listening position, the less intense the effect is. The places around the room where sound can reflect back from your monitors to your ears and potentially create comb filtering issues are know as mirror points. These locations are where you might consider placing baffles or diffusers to reduce comb filtering.
Being able to recognise subtle comb filtering is a very useful skill to have as it is generally an unwanted effect in audio production. Being able to recognise it draws you to the source of the problem and then you can address the issue. If you want to get more familiar with comb filtering, try this exercise. Set up a track of any sound you care to use and then duplicate that track. Now insert a delay plugin on the second track and adjust the delay time from 0 ms through to 100 ms. See if you can find the point at which the comb filtered sound changes to a perceivable echo.
A quick and convenient way of finding your mirror points, is to use … a mirror. Get a compact mirror and place it in locations around the room where you suspect reflections may create comb filtering issues. Wherever you can see your monitors reflected in the mirror are your early reflection points, or mirror points. Do a rough calculation of the distance sound travels direct from the speakers to your mix position compared with the distance travelled via the reflection point. If this ratio is less than 1:3 you may have comb filtering issues. If the surface at that point is hard and flat, i.e. there is not much sound absorption or diffusion going on there, you might want to reconsider your mix and monitor positioning, or think about acoustically treating that mirror point.
Any hard flat surface near your monitors may create two paths for the sound to travel to your ears – the direct path from the speaker and the reflected path via the nearby hard surface. This is a recipe for sound degrading comb filtering.
One of the most common and brutish culprits for introducing comb filtering into your mixdown environment is the desk top you have your monitors sitting on or behind. Remember mixing desks are designed with a slope for a reason, and that is to direct the reflected monitor sound below the listener’s ears.
Some speakers have been designed to sit on a desktop with the drivers angled up to the listener. The desk reflected sound does not reach the ears, and so comb filtering is avoided.
Knowing how sound behaves in an acoustic space can guide you in preparing your mixdown environment to optimise the clarity of the sound you’re listening to. An optimised listening environment leads to better mix decisions with the overall outcome of better mixes at the end of the day.
I love the little rubber stands that the Genelec 6010A’s come with, as they also allow you to angle the monitor up at your ears and work well sitting next to your computer monitor.
Leave a Reply