50 !!Chapter 3
Time compressionchanges the tempo of a track without changing the
key.
Pitch correctorscan correct poor intonation.
Transpositionchanges a key. (The ability totransposeis usually
found in computer-based sequencing programs and hardware samplers.)
Flanging(flanger) is created by using a 1- to 10-millisecond delay in
combination with filtering. It sounds like a ‘‘swishing’’ effect.
Chorus devicesare used to create a doubling sound (as well as other
effects). For instance, a lead vocal with a chorus effect sounds as if the lead
singer overdubbed the original part.
If a singer arrives at a session and the key is wrong, using thetranspo-
sitionparameter, included with most software sequencers and samplers
(hardware or software), can instantly change the key of a MIDI program.
The parameters in sequencers are adjusted by intervals, such as up one
whole step or from the key of C to the key of D.
Changing a key by using the audio transposition parameter might
sound unnatural—a vocal may sound like Mickey Mouse if the transposi-
tion is too excessive. In addition, a change of key might require changing
the octaves in which some of the instrumentation is written. For example,
a change of key might cause a bass part to sound too high, so it would
have to be lowered by one octave. This will, most likely, require rewriting
some of the parts because the range of an instrument might not accommo-
date the new key. For instance, if the lowest note on the new bass part is
notated as a low B (below the bass clef), the bass cannot play the note
because it is below the range of the instrument. The arranger has to either
select another note or play the B one octave higher. (The bass sounds one
octave lower than where it is written.)
Filters.Filters are used to eliminate or reduce sections of an audio sig-
nal. For example, a high-pass filter allows only frequencies above the des-
ignated threshold (which is adjustable) to pass, while the frequencies
below are attenuated. Conversely, a low-pass filter allows only the fre-
quencies below the threshold to be heard, and the frequencies above are
attenuated. Notch filters attenuate specific frequencies. Filters can be used
creatively to help achieve unusual sounds and eliminate unwanted fre-
quencies, such as a low hum.
Only the basics of signal processing have been discussed. Numerous
devices can create unusual results. When purchasing gear, cost is a factor.
If the budget is low, buy traditional software plug-ins, hardware effects
devices, or a combination of both. Equalizers, reverberation units, echo
units, compressor/limiters, expanders, gates, delays, and choruses are
essential to recorded sound production.
The Recording Console (Mixer)
Many of the physical functions described next can be accomplished with
the aid of a computer that is built into some consoles.