1. Sonic Fundamentals
a. Loud vs. Soft
Sound is moving air. Our ears are designed to be sensitive to these vibrations
and interpret them. In music, the term, "Dynamics" refers to whether a sound
is "soft" or "loud". The ability of a recording medium to reproduce the difference
between soft and loud is called its "Dynamic Range". Vinyl records and cassette
tapes have a limited dynamic range of 20 db or so while modern CD's and Digital
Audio Tape (DAT) are capable of full dynamic range; that's 100 db! The limiting
factor of how much of that range you get to actually hear is determined by
the speakers, and amplifiers and the room you're listening in. Read on...
b. Highs vs. Lows
We've all heard terms like "bright", "dull", "deep" and "thin" used to
describe music. Two major factors complicate this affair. The first is that
we all hear the same thing differently; one person's "bright" is another person's
"dull". The second is the accuracy or lack thereof, of our sound source, i.e.
the speakers and amplifiers. Technically, the audible frequency range for
human hearing is 20 Hertz(Hz) on the low end and 20 Kilohertz(Khz) on the
high end. Most people's hearing range falls between 40Hz and 16 Khz and in
fact, the specified frequency range of FM radio is 50Hz to 15Khz.
A typical car radio, boom box or home stereo has two EQ knobs on it. The
"Low" and "High" knobs are usually centered at 100 Hz and 10 Khz respectively
with a broad "fixed Q". "Q" refers to the range of frequencies affected by
the boost or cut and is expressed in octaves. Their effect is not subtle but
for consumer applications this is simple, convenient and usually sufficient.
The loudness button is simply a low frequency boost that compensates for the
apparent lack of low frequencies at low listening levels.
c. Speakers and Amplifiers and Rooms
This is the last step before your ears get to do their thing. Any problems
here affect the sound reproduced, and thusly, your ability to interpret what
you hear. The amp, speakers, and the room they are in, all make up the listening
environment. When your mix sounds great in the studio and terrible everywhere
else, you know something is wrong.
"Flat" is a term used to describe a system that reproduces all frequencies,
equally, more or less. Some people spend thousands trying to achieve a "flat"
room. As for me, it's great on paper, but it's not always great for music!
As long as I know what the speakers and room are doing, I can deal with it.
I like to mix on near-field systems at moderate SPL levels. This tends to
decrease the affects the room may have. My current favorites are the Genelec
1031 A's, a compact 2-way self-powered monitor. They don't lie to me. Alesis
and the Event 20/20 are recent entries into the more inexpensive 2-way self-powered
Listening level is a very subjective matter, but the ear does respond to
frequencies differently at different volumes. Constant loud levels tend to
dull the high end response of the ear, while at low levels the low frequencies
are not as apparent. As with other things in life, drugs and alcohol also
affect the ears, and usually not in a good way.