Basic Live Audio Cheat Sheet

Before you begin, make sure the snake is properly connected to the mixer, the mixer is connected to the amplifier rack correctly, the power supply for the amplifiers is plugged in but powered down, and the speakers are plugged into the amplifier rack.

Turning the Sound System On:
1. Make sure all mics and instru­ments are plugged in to the snake and any powered instru­ments (keyboard, electric acoustic guitar, etc.) are turned on.

2. Turn on Mixer/­Sou­ndboard and make sure the gain knobs are all down, the channels are muted, and the main volume faders are pulled completely down.

3. Turn on the amplifiers with gain knobs turned completely down, increase gain knobs to no more than roughly 50%.

4. Set gain structure for each channel, un-mute the channels one at a time and slowly increase the fader volume. Set a rough EQ for each channel as you do this. If need be, have the musician play solo so you can hear clearly.

5. While the band is playing at full volume, go to the amp rack and make sure there is no clipping happening in the system. If none, slowly increase amp gain until either clipping occurs or you reach roughly 75% gain. If clipping occurs before this point, decrease gain by 10-20% as excessive clipping can damage the speakers.

6. Once all channels (instr­ume­nts­/mics) have been un-muted, EQ'd and sound decent solo, have the band play a song. If you hear anything you want to change, do so and then move around the room listening to the sound from different perspe­ctives (remember, what sounds decent in one place can sound not so great in another). Continue to adjust levels, panning, EQ until you have the sound you desire.

To make an instrument sound "­bet­ter­":
Do not boost the freque­ncies you want to hear, simply remove the ones you don't want to hear.

To make an instrument sound "­dif­fer­ent­":
A tactful frequency boost can help achieve this.

Think about what freque­ncies each instrument produces. For example, a piano can produce low freque­ncies like a bass guitar, however, slightly cutting the lows from a piano can give the bass guitar more "­spa­ce" so it doesn't have to fight the piano for those freque­ncies.

If you get to a place where you are happy with the mix, step out of the room for a for a few minutes to let your ears rest. When you return, walk around the room and listen for anything you didn't hear from the board. For example, the freque­ncies from the bass guitar can be quite a bit more noticeable from a few spots than others. Work to eliminate these "hot spots".

16 Hz - 60Hz
Encomp­asses sounds which are often felt more than heard. These freque­ncies give the music a sense of power even if they occur infreq­uently.

60 Hz - 225Hz
Contains the freque­ncies of the rhythm section so EQ'ing this range can change the musical balance, making it fat or thin. Too much boost in this range can make the music sound boomy.

250 Hz - 2 kHz
Can introduce a telephone or "old time radio" like quality to the music if boosted. Boosting the 250 Hz range can give the sound a muddy quality. Boosting the 500 Hz to 1 kHz octave makes the instru­ments sound horn like, while boosting the 1 KHz to 2kHz octave makes them sound tinny. Excess output in this range can cause listening fatigue.

2 kHz - 4kHz
Too much boost in this range, especially at 3kHz, can also cause listening fatigue. Dipping the 3kHz range on instrument backgr­ounds and slightly peaking 3kHz on vocals can make the vocals audible without having to decrease the instru­mental level in mixes where the voice would otherwise seem buried.

4 kHz - 6kHz
Respon­sible for the clarity and definition of voices and instru­ments. Boosting this range can make the music seem closer to the listener. Reducing the 5kHz content of a mix makes the sound more distant and transp­arent.

6 kHz - 10 kHz
High frequency which cymbals often produce. The higher end of the vocal spectrum is here too.

10 kHz - 16kHz
Controls the brilliance and clarity of sounds. Gives "­air­" to the mix.

Equalizer (EQ) - A device that boosts or cuts selected bands of freque­ncies in the signal path.

EQ Sweep - The act of boosting a frequency and then changing the frequency being boosted until a specific (usually unplea­sant) frequency is found. Once found, that frequency can be isolated and then removed.

Feedback - The “howling” or “ringing” sound caused by bringing a microphone too close to a loudsp­eaker driven from its own amplified signal.

Frequency - The number of times an event repeats itself in a given period of time. Generally the time period for audio freque­ncies is one second, and frequency is measured in cycles­/wa­vel­engths per second, abbrev­iated as Hz. One Hz is one cycle per second. One kHz (kiloh­ertz) is 1000 cycles per second.

Gain - The variation in level of a signal. Proper gain structure within a sound system allows for maximum dynamic range and the minimum level of noise a system is capable of genera­ting.

Headroom - The available signal range above the nominal level before distortion occurs. Headroom may be thought of as a safety margin that allows room for all those dynamic peaks that give impact to music.

Peak - The high point in signal level. Where clipping or distortion begins.

Phantom Power - The +48V power supply available at the channel mic inputs, for condenser mics and active direct boxes.

Reverb­eration ("Re­ver­b") - The sound remaining in a room after the source of sound is stopped. It's what you hear in a large room immedi­ately after you've clapped your hands.

Tinnitus - The ringing in the ears that often results from prolonged exposure to very loud sound levels.

Unity Gain ("Un­ity­") - When a gain-p­rov­iding circuit is set for zero boost. Settings at unity gain typically ensure balanced signal levels and help protect against feedback.