VOCABULARY FOR THE DAY...
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Acoustics – The behavior of sound, and it’s study.
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Reverb – A sound effect that simulates different size rooms. Basically, it’s “echo”
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Dry – The sound coming from a PA system with no effects (raw sound).
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Distortion – usually an undesirable result from overloading the system... please
check and make sure your system will not blow up momentarily : )
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Wet – having reverberation or ambience.
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Early Reflection – The first echoes in a room, caused by the sound from the
sound source reflecting off one surface before reaching the listener.
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Wave – a continuous fluctuation in the amplitude of quantity with respect to time.
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Wavelength – The length of one complete cycle (peak to peak, trough to trough)
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Sound Wave – Short for Sound Pressure Wave (a wave of pressure changes
moving away from something that is vibrating between 20 times a second and
20,000 times a second.
LETS TALK ABOUT REVERB
What is reverb? From our Daily Class Questions we learned that reverb is
basically an effect used to simulate a room. It can make you sound like you are in
a huge gymnasium, or a tiny practice room.
Reverb works wonders for making something sound more full and bigger than it
really is… but what is it really changing?
SOUND WAVES!
Did you know that each and every sound is a real, physical WAVE!? Here’s what
some different sounds LOOK like…
BACK TO REVERB…
So, now that we learned briefly about sound waves, let’s talk about how they travel…
Sounds travel in all directions, and if the object making the sound is stationary, at
a constant speed.
If you were sitting in an empty
room listening to music from
one speaker, this is what it
would look like…
REVERB CONTINUED…
Notice that there are three different points of contact for the sound in this
picture… the “direct signal” and then two “early reflections.” For our discussion,
reverb comes from the early reflections. Notice that the path each early
reflection takes is longer than the direct signal? This is what causes the delay, or
reverb.
REVERB CONTINUED SOME MORE…
Now that you understand how sound bounces and travels, here’s what that room
REALLY looks like…
SO HOW DO YOU USE IT ON YOUR MIXER?
Here is what a typical sound board (mixer) looks like…
EVERY SOUND BOARD IS DIFFERENT,
BUT THE SAME…
As you can see by looking at the pictures and looking at our synthesizer cart’s
sound board, they are VERY different. However, they are also VERY similar.
Reverb is usually found in the effects channel on your sound board. You can
control how much effects you want in each signal by turning the EFX 1 or EFX 2
knobs left or right. On our synthesizer cart, we have a separate knob specifically
for reverb.
ENOUGH ABOUT REVERB!!! WHAT ARE THE
OTHER GAGILLION KNOBS AND SLIDES FOR!?
Every sound board can be broken down into three main parts… the volume,
settings, and effects.
Let’s talk about the volume first…
Most mixers have slides that control the volume.
We have mixers that utilize both styles...
SETTING EACH CHANNELS VOLUME OUTPUT
There are three main areas of volume to be concerned with… first is the individual
channel volumes, second is the monitor volume (we will skip for now), and third is
the main volume, or “Master Volume.”
It’s actually real simple… let’s say that we are running sound for someone who is
singing and playing a guitar.
You want to adjust the individual volume of each component (voice/guitar) to
where it sounds good to you! You will typically want more vocal sound than guitar
sound, so you will set your channel volume to the desired level for each channel.
Then, you can adjust the main (master) volume to how loud you want your mix to
be.
THE SETTINGS
What are all those knobs for!?
Here are your main settings every sound board
will have (we will break into detail on each)...
Gain/Trim
Highs
Mids
Lows
AUX / MON 1 and 2
EFX
GAIN/TRIM/LEVEL
On most mixers, the very top channel setting will be the GAIN knob. On others, it may
be called TRIM or LEVEL, but it all means the same thing.
This knob is used to deliver the correct amount of signal the board receives of that
particular voice or instrument. It can get extremely complicated using this setting, so
here is the basic rule...
Make sure all the volume is turned off (muted) on the entire board, each channel AND
main volume. Turn the channel you are setting, on. Play the instrument at it’s loudest
part and adjust the gain knob up just until the instrument begins to peak, or hit the
“red” on the light board. That’s it... Don’t touch the gain knob again! Set it, and forget
it!
One of the most common mistakes people make is using the gain knob to adjust volume...
HIGHS
The “Highs” setting controls how much high frequency is placed in the mix. The
instrument, voice, or sound you are controlling should determine how much high
frequency is put into the mix.
For example: A flute would need more highs than a tuba.
Setting too much high frequency can be a bad thing, however... You need to use
your ear and determine what sounds the best. While there are limits to how you
can set it, there is no fine line that determines right from wrong.
MIDS
The next setting you will have on your channel is MIDS. Depending on the sound
board you may have two knobs, High-Mids and Low-Mids, or just one knob that
controls all the Mids.
The MIDS setting adjusts just what it sounds like... the middle frequencies.
Nearly all voices and instruments need some MIDS put into them in order for
them to sound natural... again, how much depends on your ear. With the
exception of the extremes, there is no right or wrong.
LOWS
Again, this setting adjusts what it says... the low frequencies of the voice or
instrument. How much you put into it depends on your ear. There are a few
things to keep in mind with lows, however...
A flute does not need much LOWS in it at all... it plays mostly high frequency stuff.
A Tuba needs more LOWS in it... it plays mostly low frequency stuff.
An instrument that plays the entire spectrum (low-high frequencies) will need
some LOWS, MIDS, and HIGHS... but at a roughly balanced level depending on
the sound you want to get.
AUXILLARY / MONITORS
Auxillary, or AUX knobs can be found on most mixers, but not all. These knobs
control the amount of OUTPUT sent to their assigned device. For example...
My in-ear monitors that I use when drumming are run through the AUX 3 channel
on our church’s sound board. If I need more lead guitar in my ears, the sound
guy goes to the lead guitar’s channel and turns UP the AUX 3 knob, thus giving
me more lead guitar volume in my ears.
The most important thing to remember is that the AUX channels are OUTPUT, NOT
INPUT.
MONITORS work the exact same way the AUXILLARY knobs work... Most boards
have a MON 1 and a MON 2 knob which allows for 2 stage monitor mixes.
EFFECTS (EFX)
Effects, or the EFX knobs, are on most soundboards but not all. Effects can be a
bit tricky to deal with so here are the basics of how they work...
Most boards have 1-4 EFX knobs. You must first set your effects (more on that
later) over on the “effects portion” of your board. Once you have designated a
specific effect to an EFX channel (for example you put reverb 24 in EFX 2) you can
adjust how much effects you put in each channel.
NOTE: On most boards you cannot have different effects for individual channels...
for example: On channel 1, EFX 2 is reverb... therefore on channel 2, EFX 2 can
only be reverb. You cannot set EFX 2, on channel 2 to anything else.
OTHER ODDS AND ENDS...
Other buttons your mixer has or may have on it...
MUTE button- Mutes everything for that specific channel
LINE/MIC button- Adjusts the signal based off of whether you are using a mic
cable or a ¼” cable.