As the title suggests, in this topic we will talk about isolating audio signal. I believe in a very simple way of mixing an audio signal – “Frequency Isolation” is what I would like to call it. If you want a clean mix, make it clean as early in the signal chain as you can, the earlier the better. This is something we tend to forget because of all the technology we have at our disposal today. Digital consoles give us the flexibility of having equalizers, gates, compressor, filters, and all kinds of effects on every channel on the board and because of this luxury I have seen many drifting from the basics.
There are numerous ways of achieving a nice clean signal and I will elaborate on a few here.
1. Choose the right microphone. Most basic and yet the most effective way of getting just what you want. Every microphone has a specific purpose behind its design. Take time to read the specification sheet of mics that you use, they all have a response curve and sensitivity. See what suits your need best. Don’t go around putting a Shure SM58 on a Hi-Hat when you have something like a Shure SM81 sitting around doing nothing. Yes there are times when we are left with no choice and have to use the wrong mics but why so it when you have a better option.
2. Position the microphones right. Choosing the right microphone doesn’t do it all, placement of the microphone is equally important if not more. Too close to the source could be more disastrous than too far from the source at times. Play around 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 allowing it to pick other sounds from around it. Right placement and distance will give you just the right gain structure on your console.
3. The right gain. Now assuming you have good cables and everything to get the signal to your console next would be the gain. Setting the right gain is most crucial to your mix. The gain will affect the output to the PA and will also affect your monitor mix. So once you set this there is a very small chance that you can change it without disturbing your monitor mixes. What is the right gain? Like every other answer in the audio business, it depends. Right gain according to me is something that will let me run my channel faders and master fader at Unity without feeding back. But again depends on your taste and situation.
4. Filters. Use whenever needed without thinking twice. Specially high pass filters, for example on Hi-Hats you don’t need any information below 500Hz, take your high pass all the way to 500Hz. Do this on all channels. Only two channels you won’t need is the Bass drum and Bass guitar, but again there are exceptions. Use wisely.
5. Equalizers. If you have decent sounding instruments, well placed mics and properly tuned PA you won’t need much of this. Try not to use too much of eq. Always cut frequencies, avoid boosting frequencies on the equalizer. You can even use Equalizers when you have fixed Low Cut filters to help take out the unwanted lows completely.
6. Go back to step 1. Go back and check where you can improve if you aren’t satisfied with what you get. Keep making mental notes on mic placements and other things you did when you get satisfactory output. Try and replicate it at various venues till you get a formula that works for you.
Hope this help in some way. Get back to me if you have any doubts or if you feel I need to correct something’s here. Happy Gigging!
