Sound Ministry Series Part 8 - The AUX buses

So, what's a bus? Well, it's something that gets you from one place to another! On a mixing console, when we see the word BUS, that's just what it is - a routing device to get the signal from one place to another.

The AUX (which stands for auxiliary, meaning secondary or additional) buses are used to create a second, third, fourth or even fifth mix (with the front of house mix being first) that can be used for stage monitors, recording of sermons and worship, cry-rooms, broadcast, etc.

Each channel should have knobs labelled AUX1, AUX2, etc. These are used to control the level of that individual channel in the AUX mix. Somewhere on the far right of the desk should be other knobs or sliders also labelled AUX1, AUX2, etc. which are used to control the overall volume of the AUX mix. Near the top right of the desk, either on top or on the back, there should be outputs for each AUX bus for plugging in a cable to take the signal, well, anywhere you want!

Here are some worked examples:

Recording the sermon

Plug your recording device, like a computer soundcard or a tape recorder, into their AUX1 output. Increase the volume of the overall AUX1 volume (the one on the right of the desk) to about halfway. Use the AUX1 control on the preacher's microphone channel to adjust the recorded volume. Your AUX1 bus is now your recording mix! You can add other channels to this mix by using their AUX1 controls.

This idea is the same for a cryroom. Just plug the cryroom feed into the AUX1 output.

Stage Monitors

Remember that each AUX bus can provide you with a separate monitor mix (depending on how many monitors you have). For now, let's use AUX2 and AUX3 for vocal and instrument monitors respectively (remember that AUX1 is our recording bus).

Plug your monitor sends into their respective AUX outputs on the mixer. Adjust the volume of each AUX mix to about halfway. Ask the band to play, and let them help you to determine how much of each instrument or vocal needs to be added to each monitor mix. You can also walk up there yourself and take a listen, but that's going to involve a lot of walking back and forth! The vocal mix (AUX2) will need more vocals and less instruments, and the instrument mix will need the opposite, but still enough vocals to hear the words so they don't get lost!

Finally, always ensure that your AUX buses are "pre-fade". There should be a button on each channel allowing you to set your AUX buses to pre- or post-fade. If they are set to post-fade, any change you make to that channel in the main mix will also affect the monitor mix. For instance, you turn up the piano in the main mix and it also goes up in the monitor! Pre-fade allows you to maintain completely independent AUX mixes.

The only time you may want post-fade AUX buses is if you are controlling an effects unit from an AUX bus. If this is set to pre-fade, the sound from the effects unit will still be heard when you turn the channel down.

Remember, however, that if you have your AUX buses on pre-fade, the MUTE switch won't work on the AUX buses - i.e. you will still hear a "BOOM" on the monitors when someone unplugs even if the channel is muted - you will have to turn down the AUX buses separately.

Comment if anything's still unclear.

Next time: The PAN control

Sound Ministry Series Part 7 - A Final Word on EQ

Before we move on to the AUX buses, maybe it would be good to have a final word on EQ.

The hard part of mixing with EQ is the time spent learning what different frequencies sound like. When most of us hear a low sound, we imagine that's it's lower than it actually is. Same for highs - we imagine they are higher than they actually are. So, we need to learn more or less what 120Hz sounds like, what 2kHz sounds like, and so on. We also need to learn what frequencies are produced by what instruments and voices. It might sound like hard work - and any ministry is! - but spend time playing with the EQ whilst you're mixing and you will definitely learn a few things.

Always cut rather than boost. If a vocal is missing some clarity, try and cut some 240Hz before boosting the 5kHz. This ensures that you keep the overall level under control and prevents problems caused by too many boosted frequencies (like feedback).

Lastly, remember that EQ tends to relate across channels. If your vocal is getting lost, try and create an open space for the vocals by reducing a little 2kHz-5kHz in the other instruments. This will help balance the sound as a whole.

Mixing is more than adjusting volumes between instruments and voices. It is ensuring that the total sound that comes out of the speakers is comfortable, enjoyable, intelligible and audible for those hearing. The EQ is the steering-wheel to get you there!

A document that has helped me hugely is http://www.digitalprosound.com/2002/03_mar/tutorials/mixing_excerpt1.htm.

Next time: (I promise!) The AUX buses

Sound Ministry Series Part 6 - The Low Frequency EQ Knob

Hey guys. It's been a while since the last post, so let's dive right in!

The next knob on your channel after the mid range is usually your low frequency. This control typically allows you to boost or cut everything from 80Hz or so and below. Remember that if your PAD switch is in, you are already cutting the lows to an extent. Therefore, the Low knob and the PAD switch are interactive.

These low frequencies are going to really affect the fundamentals of the rhythm section (bass guitar, kick drum, 'body' of acoustic guitar sound, bottom end of the keyboard, etc.) They can give the music a more powerful sound in larger doses, or a bit more body in smaller doses. That's when it's used right. Used wrong, it will make the music sound boomy or muddy, and if cut too much can make everything sound 'thin'.

Be careful with lower frequencies. Lower frequencies are what we call "omni-directional" - they go everywhere in all directions, even behind the speaker! This means that a little boost goes a long way.

Be aware, also, that as you get lower you will begin to feel the sound more than hear it. This means that even if you can't hear the difference you are making, you might still be reprogramming someone's pacemaker in the 3rd row (just kidding).

On vocals, low frequencies won't to do much, especially if you have the PAD switch in to reduce handling noise.

Next time: the AUX buses

Sound Ministry Series Part 5 - The Mid Frequency EQ Knob

Next on the channel we have either one, two or four knobs that control the midrange. When we talk about midrange, we mean the frequencies between the highs and lows. Most of the sound is actually concentrated in these frequencies, so your mid range control is pretty powerful!

If you have 1 knob called "MID", it works the same way as your high and low controls, boosting or cutting a very large range of frequencies.

On better mixers, you will have a MID control and a FREQ control. The MID control does the cut and boost thing, but the FREQ control allows you to decide on which frequency the cut or boost centres on. Imagine a bell-curve (up for boost, down for cut) where you are able to move the apex left and right across different frequencies to get a visual image of this in action.

If you have the luxury of four knobs, you have a LOW MID with a FREQ control (around 800Hz) and a HIGH MID with a FREQ control (around 3kHz). This allows you the best management of your midrange.

To get to know how these controls behave, it is important that you grab a mic, cut the MID knob all the way, and then turn the FREQ knob backwards and forwards while speaking into the mic. Do the same with with the MID knob boosted all the way, and you'll quickly hear what's going on.

The best way to use these controls is to listen out for offending frequencies in instruments or voices, then cut your midrange by 1/4 and 'sweep' your FREQ control until you find the point on the dial where the problem lessens. Remember to look at what frequency you have stopped on and try and remember what it sounds like - it will help you get there quicker next time.

The best thing to do with this control is to play with it and listen for the results. Try boosting a little on your singer's mic and then sweep until you find a pleasing result.

Next time: the Low EQ knob