So you find it easy to isolate musical instruments with different frequency characteristics. For example if the mix is only consist of a simple vocal and a bass guitar; then even without any effects the vocal and the bass would stand out naturally because they are occupying completely different frequency characteristics.
As you might know, vocals frequencies are common around 300Hz to 3000Hz while bass guitar obviously occupies below 200Hz; so finding space for them in the mix is not really a serious problem. But what about you have two or more instruments in the mix having the same frequency characteristics? This is where you can see a lot of challenges in the audio mixing process because it is becoming hard to isolate them properly in the mix.
The following are very common audio mixing issues:
1.) Vocals vs. the Background vocals – particularly if the lead and background vocals are both female or both male. But in case of a male lead singer with female background vocals or vice versa; it won’t be a serious problem since female voices tends to occupy at a higher range of vocal spectrum.
2.) Kick drum and bass guitar – this is often a common source of audio mixing issues.
3.) Guitar vs. Vocals vs. Other string or wind instruments (violin, flute, etc.) – these instruments have the same frequency characteristics, becoming harder for them to isolate properly in the mix.
Effects that you can use to improve clarity and space in the mix
For best results, you would be using the following effects:
1.) Parametric EQ –Basically the principle is that; supposing two instruments sound the same (or occupying the same frequency spectrum); you can use EQ to make them sound different in the mix. This is done by applying the concept of “contrasting EQ”. This works by boosting a certain frequency range favoured for that first instrument for clarity/definition and then cutting that same frequency range on the second instrument. Make sure that the amount of cut and boost are in the same values but in opposing direction. The Q should be the same as well. See an example EQ setting of two instruments occupying the same frequency spectrum applied with “contrasting EQ” effect:
First instrument: Boost +6dB 400Hz at Q=1.4, Cut -3dB 2000Hz at Q=1.0, Cut -3dB 8000Hz at Q=1.4
Second instrument: Cut -6dB 400Hz at Q=1.4, Boost +3dB 2000Hz at Q=1.0, Boost +3dB 8000Hz at Q=1.4
What’s the expected resulting sound of contrasting EQ? The EQ applied can make them sound distinct in the mix. For example, the second instrument has more mid-frequency presence and sibilance as compared to the first while the first has more tone at 400Hz. When played together, you can hear both instruments clearly because they are now made to sound distinct using EQ. Other example that perfectly applies this concept is mixing bass guitar. You can read that tutorial to learn more about this technique. This will work with any instruments in the mix. You just need to decide which instrument should occupy that specific frequency range that would give them the best sound definition and clarity. And then you apply contrasting EQ technique.
2.) Reverb– less reverb puts instruments in front of the mix while more reverb puts them more in the background. When used properly, this is a very effective method to assign space for two similar sounding instruments. This will improve the clarity of the instruments in the mix.
For example in a lead and background vocals; it is common for the lead vocals to be up-front in the mix because in reality the lead singer is the one that is performing in front/center of the stage and near to the listeners. Therefore by adding less reverb on the lead vocals, you can push it to sound more up-front while adding more reverb on the background vocals to make them sound like they are on the background.
3.) Panning- this is a very important effect in finding space and isolating instruments in the stereo mix. This effect works best when combined with EQ and reverb as panning alone is insufficient to make them sound distinct and unique. To implement panning, imagine the artist performing live onstage. The vocals should be in the center, the guitars on both left and right, bass in the middle and some keyboards at half-way left or right. To make them sound more distinct and finding a well-defined space for your instruments, use panning wisely with reverb.
Panning and reverb
Center instruments should sound as dry as possible while those in the hard left and right have more reverb effect applied since they appear farther from a stereo listener perspective. For details, you can read this tutorial for some excellent tips on how to apply reverb on your mix with panning.
4.) Compression – you can also use this effect to improve the sound and clarity of the instruments in the mix. For example, a compressed snare sounds very different to raw unprocessed sound. This can produce distinct results in the mix when played together. Other use of compression is to reduce the dynamic range of beat instruments like bass guitar in order to make them sound “consistent” and “steady”. For example you have noticed that the bass does not still cut through in the mix after EQ adjustment primarily because the bass guitar player dynamics is not solid and consistent. By applying compression, you can make the bass shine and cut through the mix and every bass guitar notes would now sound clear. Read more about this in audio compression tips.
Content last updated on June 17, 2012