Effects Processors
THE DIGITAL RECORDING STUDIO: A Practical Guide to Music Recording
By: James@audiomecca, copyright 2007.
Effects Processors
Audio Effects, and Signal processing tools for the recording studio.
Adding effects to your mix can create professional and unusual
characteristics to your recordings. They can add warmth to acoustic instruments, put life into your virtual instruments, or soften a brittle sounding sample. They can
also strengthen an electric guitar track, or create the illusion of a vocal
performance from an acoustically sound cathedral.
This
section explains:
- How
audio processors can benefit your music recordings.
- What
the difference between an effects processor and a signal processor is.
- The specific functions of audio processors.
- Hardware
and software audio processors.
The
two root-categories of audio processors are:
- Audio Effects (fx) Processors
Audio processors edit the waveform, and then send the audio file with the signal changes to the output.
They can do this by recording a new audio file over the old one, adding the processed effects. Some processors allow you to preview the effects in real time from within the multi track recorder. This lets you monitor the changes, or compare and contrast the new signal before the
recording is permanently rewritten.
Effects processors manipulate the waveform it processes, but in a different way than signal processors. Effects processors can be understood as artificial additions to a recording. For example, adding chorus replicates a recording or track. This duplicate signal is changed and a slight change to the original pitch is added. This effect results in a more pronounced section or louder, doubled, highlighted, instrument section. Signal processors can be understood as natural modifications that control the signals
output. For example, Equalization adjusts the output of frequencies. The
modified frequency response can be used to highlight a high hat by 6db at
15khz, which would make the frequency have a higher sizzling sound to it. The
frequency spectrum is the scale of frequencies heard by the human ear. This is understood to be 20 HZ – 20KHZ.
Note that audio processors only process audio. (There is now such a thing as Midi Effects, but they are much different and not explained in this section) This means that every audio
software effect you use within your home recording environment will require
more resources from your computer.
Manipulating
audio requires more DSP and hard work than midi and data. Further, FX
processors and audio tracks can be taxing on your CPU. Use discretion according
to your digital audio workstation’s DSP power. Hardware processors can be
integrated units or standalone modules. Both can be used in a versatile way and
are not outdated, yet. They are both very capable in audio processing power.
Hardware processors are usually more expensive than competitive music editing
software applications. Whereas they can be more reliable than music software due to the fact that they are not run on a computer. They both have their
advantages and disadvantages.
Hardware and Software processors
- FX processing units can be bought as hardware modules and/or music software FX processors.
Music software processors, also known as
plugins, are typically designed to emulate hardware units. As the hardware
ranges from decent, to state of the art; the same is true for software
processors. Both do the same thing, just have a different form of interface
and control. In most cases, since the software FX processors replicate a model
of hardware, the only practical difference is instead of using your hands to
adjust the knobs, you’d adjust the knobs on your screen using your mouse or control surface. Thus, I will cover general functions and results of popular audio effects used in the modern home
or pro recording studio.
Signal
Processors
Compressor: Acts as a volume control
that regulates the signal when it gets too loud.
Limiter: Prevents the audio signal
from peeking above a preset level, this level, is determined by you. Limiting
helps keep an overall balance, as inconsistent vocal takes and DAT overloads
are common in all recording studios.
Noise Gate: Gates are used to smooth
the pauses in between active parts of your recordings. They automatically
decrease the gain when its level falls below your pre-set volume. (I.E the
breathing or moving around that gets recorded in between vocal sections.) These
are very helpful and should be experimented with hands on tweaking.
Equalizer: The process of
equalization is adjusting the way a frequency range responds. (Adjustment of
frequency to affect its placement in the mix.) This is generally used to
accentuate a frequency range or exclude a certain frequency, dependant upon the
producer’s vision and recording techniques.
Effects
Processors
Chorus: Produces a slight pitch
delay that makes the recording sound fuller. Chorus gives the illusion of
additional performers/accompaniment, it somewhat highlights a given section.
Flange: Flanging is the process
of replicating the original sound, and then delaying that replicated signal.
This alters the original sound and makes a swirling, swooshing, sound. Again
these effects are “audible,” so needless to say it’s much easier to understand
them by using them.
Reverb: Is simply a reflection of
sound that repeats or slowly fades. Reverb mimics what you hear when you scream
into an auditorium. This slowly fading sound, is the decay of reverberation.
Delay: A delay processor simply
makes a signal lag. This lag is what you hear and it is the interval between
the original signal and the delayed signal.
Echo: Whereas reverb is the
decay of the original sound, echo can be explained as the original reflections.
For example, Screaming into the grand canyons you hear a very loud reflection
of what you screamed for a few repetitions…This is the echo…The slow decay of
the noise is Reverb.
Audio processors are available for the hardware or software based
recording studio. They are available as physical units or software plugins. These additions can be
used to boost a second rate mix to a commercial quality record. The first step
is to understand what audio processors do. The next step is developing
techniques for how to implement the right effects when needed, to add dynamic
and realistic characteristics, or entrancing sound scapes to your digital audio tracks.
Happy Recording,James
