Clean Audio Signal for the Best Mixes

I believe in a very simple way of mixing an audio signal – Frequency Isolation. I use frequency bands relevant to instrument or source and clean out the rest. This way I create more space for other instruments to comfortably to sit in the mix.

There’s something we tend to forget as a result of all the technology we have at our disposal. Digital consoles give us the flexibility to use equalizers, gates, compressor, filters, and other effects on each channel on the board. Because of this luxury, we tend to drift away from the basics. However, if you want a clean mix, make it clean early in the signal chain – the earlier the better.

There are numerous ways of achieving a clean signal and here are some suggestions in their intended order:

1. Choose the right microphone
This is the most basic and effective way of getting your desired result. Every microphone has a specific purpose behind its design. Take time to read the specification sheet of mics that you use, as they all have a response curve and sensitivity for a specific use. See what best suits your needs and don’t go around putting a Shure SM58 on a Hi-Hat when you have something like a Shure SM81 available. There are situations when we have to use the ‘wrong’ mics due to lack of better options, do it wisely. If you have to chose between Shure SM58 and SM57 for hi-hats, what would you use? I’d use the SM57. Nothing beats making the best use of available resources.

2. Position the microphones right
Choosing the right microphone doesn’t end the story, placement of the microphone is equally critical. Positioning it too close to the source could be more disastrous than keeping it far from the source. Play around and experiment with the distance, angle and placement over the source. Try not to get too close to avoid the Proximity Effect but don’t go too far either, allowing the mic to pick more ambient noise that your intended signal. Getting your placement and distance right will give you the required gain structure on your console.

3. The right gain
Once you get good cables and the right equipments to get the signal to your console, the next step would be getting the right gain. Setting the gain is most crucial to your mix. Gain will affect the output to the PA and affect your monitor mix. So, once you set it, it is unlikely for you to change it without disturbing the monitor mixes. Well, what then is the right gain? Like every other answer in the audio business, it depends. Right gain according to me is one that will let me run my channel faders and master fader at Unity without feeding back or too much leakage from other instruments. Again, this completely depends on your taste and situation.

4. Filters
Use filters whenever required without thinking twice – especially high pass filters. For example, on Hi-Hats, you may not require any information below 500Hz. You can take your high pass all the way to 500Hz. Repeat this on all channels at desired frequency. The only two channels where you won’t need filters are probably the bass drum and bass guitar. There are exceptions, so use it wisely. The same goes for low pass filters – if your board allows it.

5. Equalizers
If you have instruments that sound decent with well-placed mics and a properly tuned PA , it’s likely that you wont need equalizers. Try not to use too much of EQ. I prefer to cut gain on frequencies, and avoid boosting on the equalizer. You can even use equalizers if you don’t have fixed low-cut filters to help erase the unwanted lows completely.

6. Go back to Point 1
Go back and check how you can improve your sound. Keep making notes on mic-placements and other aspects when you get satisfactory output. Try and replicate it at various venues till you find a formula that works for you.

Tip: You could call carry known good recordings of tracks with the instruments and style of music you are mixing for the day as a reference. Listen to the tracks before you start mixing and also after you are done with sound check to see how you fared. If you don’t want to play the tracks on the PA you could use a good pair of headphones to listen to the tracks even during sound check.

Hope this post has helped you in some way. Feel free to get back to me through comments if you have any doubts or if you feel I can add any information here.

Happy Gigging!

Update: 24 May 2016 – Minor edits and added last tip on reference tracks.

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