AE 282: Spring 2004
INSTRUCTOR: Eddie Ciletti
WEEK-1: Summary,
Assignments,
Reference
Material and Links
SUMMARY
Preparation for the Final Exam starts
now. Each week you must submit a progress report, in week-2, all
that's required is a paper and e-mail outline of your plans. The
rhythm tracks should be completed no later than week-5 so that you can
deliver a rough mix by the Mid-Term Exam. The Final Mix is the Final
Exam and is due week-12.
In the first class, students were asked
a range of questions to determine strengths and weeknesses both in the
practical aspects of actual recording and mixing as well as general audio
knowledge. We pumped a 40Hz tone into the studio and walked around
listening for nodes - places where the tone was lost or was loud - to emphasize
one of the reasons that low frequencies can be so elusive.
One of the most common problems is the
bass-heavy mix. At the other end of the spectrum, it is important
to act upon instinct - if a track or mix seems too bright, then immediately
take action before the ear becomes accustomed to the problem. While
the term, "Bass Management" became an issue with the introduction of Surround
Sound, it can be globally applied to all recording situations.
ASSIGNMENTS
-
Determine how the feed to the SSL's Channel
Insert Patch Point changes with the various status options.
-
Submit an outline of your plans for the final
project.
REFERENCE MATERIAL
The Equal Loudness Curve details
the ear's non-linear sensitivity to the audible spectrum. 20Hz to 20kHz.
The ear is least sensitive to bass frequencies when the overal Sound Pressure
Level (SPL) is low, the "curve" at the threshold of hearing being most
severe. While it never actually flattens out, the curve does get
smoother as SPL increases. For the audio control room, 85dB-SPL is
considered a reference level. All engineers should be aware of, and
have access to, a sound pressure level meter. It is important to
limit exposure to excessive SPLs to preserve hearing. If your
instinct and preference is to monitor at lower levels, keep the Equal Loudness
Curve in mind as most control rooms and monitors are not compensated for
lower level listening. The "fix" would simply be to re-voice the
room / monitors by increasing the low frequency response. On a consumer
audio system, you hope this is accomplished by a front panel switch, although
it is sometimes integreted without the ability to be disabled.
Links begin here.
More Links BELOW
The Proximity Effect of directional
microphones (cardioid and figure-of-8) is the increase of low frequency
amplitude as the microphone is placed closer to the sound source.
Relative to all that was explained about the Equal Loudness Curve, this
can create the illusion of the sound being "right" when in reality there
is a good chance that a bass-heavy foundation is being laid. This
may create problems in a rhythm track, for example, when overdubs are likely
to be referenced, and possibly re-voiced, to "fit the track."
Armed with these two bits of information,
students are advised to skeptical about all Monitoring Systems until proven
worthy.
WHERE DOES "THE SOUND" COME FROM?
It is important to understand the difference
between sonically "neutral" equipment and gear that imparts "color."
In electronic terms, "neutral" best desribes the primary goal of the classically
trained design engineer - Linear Amplfication. Before the Integrated
Circuit, gain was accomplished one stage at a time, using discrete components
such as a vacuum tube or a single transistor.
Discrete designs are generally capable
of linear operation when used conservatively, in the nominal region with
adequate headroom. But, they also have a non-linear region between
nominal and just before clipping. Hard clipping is obvious and, unless
going for an effect, is avoided. However, the non-linear region has
a way of "dealing" with transients in a way that is far less obvious.
The effect is similar to a peak limiter
- the signal is absorbed and somewhat reduced from peak-to-peak.
In its place are added harmonics, the "nice" way to say that a complimentary
distortion is added to the equation. This sound is often referred
to as "warmth," a harmonic richness that adds to the RMS or average level
even while diminishing the peak-to-peak or transient amplitude. This
is what "classic" vintage gear is all about. See Table-1
for examples of both types fo gear.
