- Sample
and Hold
- A circuit or
function in early synthesizers that enables the instantaneous value (voltage)
of a waveform to be captured, and
continues to output that value until the next sample is taken. This voltage
is then used to control some other parameter in the synth such as a filter.
Depending on how they are used, a sample and hold circuit can produce pretty
random sounding fluctuations in one or more aspects of a sound. A good example
of sample and hold applied to filter cutoff is at the beginning of the Emerson
Lake and Palmer classic, Karn Evil 9.
- Sample
Dump Standard (SDS)
- The MIDI Sample
Dump Standard is a method of sending digital audio sample data from one machine
to another via MIDI connections. Due to the bandwidth limitations of MIDI,
SDS transfers can be quite slow, but are an effective way to share sample
data between samplers, or between samplers and computer-based sample editing
software.
- Sample
Rate
- In a digital
recorder or sampler, the sample rate is how many times per second the source
material is being "sampled" or recorded. Sample rate affects the
frequency response of the final recording or sample; the highest frequency
that can accurately be sampled is 1/2 the sample rate. In general, the higher
the sample rate, the better the sound quality. But, the best sample rate to
use will depend on your application, your gear, and the amount of storage
available (the higher the rate, the more storage required). CDs use a 44.1
kHz sample rate, while DAT recorders often default to 48 kHz. Multimedia applications
may use rates of 22.05 kHz or even 11.025 kHz for maximum efficiency.
- Saturation
- Saturation refers
to the maximum amount of magnetism a magnetic tape can hold. Attempting to
add more magnetism to the tape's oxide particles will result in distortion.
Normal record levels do not generally approach saturation as distortion will
be introduced before saturation is reached, especially in the low frequencies.
High frequencies normally do not saturate as they have a tendency to self-erase
during recording.
Engineers using
analog tape often make use of tape saturation as an effect. By carefully
controlling record levels, compression, warmth, and fatness can be added
to a signal - all part of the much-heralded analog "mystique".
- SCMS
- SCMS is an acronym
(pronounced "scums") standing for Serial Copy Management System.
This nefarious little "feature" was designed by the ever-paranoid
record labels to prevent evil-doers from digitally cloning CDs. Usually found
on the S/PDIF ports of "consumer" (was there ever REALLY such a
thing?) and "semi-pro" DAT recorders, SCMS is a bit flagging system
that prevents digital copies from being made of digital copies. This means
you can make as many digital copies of your original DAT tapes as you like,
but you cannot digitally make copies of any of those copies. Beware of SCMS
if you are sending backup DAT copies of your master tapes to a CD duplicator,
or a collaborator. They may not be able to digitally transfer your work to
another tape or media!
- Scrub
- A useful function
found on many tape, disc, and hard disk based recorders, scrubbing is manually
moving through an audio waveform. Because audio can be scrubbed backwards
or forwards at rates much slower than real time playback, scrubbing allows
for precise location of edit points.
- SCSI
- Pronounced "scuzzy,"
this acronym stands for Small Computer Systems Interface. SCSI is a hardware
interface incorporated into computers, disk-based digital recorders, samplers,
and other microprocessor-based equipment. It allows for the easy connection
of a variety of peripherals such as hard drives, removable media drives, CD-ROM
drives, scanners, and more. One SCSI controller can support up to 7 peripherals,
each having their own unique "id" or address. The first and last
items in a SCSI chain must be terminated for proper operation. The "theoretical"
maximum length of a SCSI chain is 19 feet, but in practice, the chain should
be as short as possible!
- Semitone
- Literally, half
a tone. Also known as a half step. A way of describing a musical interval
of pitch. In our equal tempered scale system we
use there are 12 semitones per octave.
- Send
- An output on
an audio device used for routing signal to an external device, such as a reverb,
delay, or other processor. Typically, sends are paired with returns, which
accept signal coming back from the output of the processor. The more sends
a mixer has, the more flexibility you will have in routing signals around
your studio.
- Sensitivity
- In audio terms,
sensitivity is the minimum amount of input signal required to drive a device
to its rated output level. Normally, this specification is associated with
amplifiers and microphones, but FM tuners, phono cartridges, and most other
types of gear have a sensitivity rating as well. In general, higher sensitivity
is better (less input signal required for full output), but there are definitely
situations where a device can be TOO sensitive (picture a very sensitive microphone
in front of a wound-up Marshall guitar amplifier!) resulting in unwanted distortion.
- Serial
Time Code
- Editing devices
which can be controlled by computers, have a connection called a "serial
control port" or RS422 port. These devices communicate with the computer
and are controlled via commands in a serial data protocol. Serial Time Code
is a means of transmitting time code over the same
data stream that carries this control information for the purposes of synchronization.
Some of these devices have no SMPTE Time Code port,
but send and receive time code via these control ports. Other devices send
and receive only transport commands over their serial ports, but require a
conventional time code connection in order to read time code.
- 70-Volt
System
- A type of speaker
distribution system where transformers are used at the output of an amplifier
and at each speaker in order to provide a constant voltage of, in this case,
70.7 volts that can be tapped by multiple speakers. These lines can be run
great distances with less loss and can have many speakers on them as compared
to typical high current speaker lines. These types of systems are generally
employed in situations where an amplified signal must be distributed over
vast areas without a need for very high SPL (see WFTD archive "Sound
Pressure Level") in any one area. This is typically the type of P.A.
system you will see in schools, churches, business offices, and commercial
facilities like malls and shopping centers.
- SFSK
- Abbreviation
for Smart FSK (see WFTD archive FSK). Smart
FSK was adopted a few years after FSK and MIDI had been in common use. Professionals
were all switching over to SMPTE based systems which were much more reliable
and accurate than the old FSK based ones, but the cost of SMPTE readers and
generators was extremely high at the time, and units that translated it to
MIDI were yet another separate big expense. So a few companies, most notably
at the time were TASCAM (MTS30) and JL Cooper (PPS1), adopted Smart FSK which
added the ability to include location information to the FSK signal. These
boxes, which translated between MIDI and SFSK and back again, were much less
expensive than the SMPTE based ones and they still allowed users the luxury
of starting from within a song and having their sequencer locate to the proper
spot to begin playback. Also, because the system was continually able to "locate"
itself the common problem of FSK devices getting one or two beats behind (due
to drop outs and glitches) went away. Nowadays SFSK isn't used much because
SMPTE and MTC based systems are so inexpensive, as well as being even more
versatile and reliable.
- Shedding
- The phenomenon
of recording tape oxide (see WFTD archive Oxide)
coming unglued from the backing (the tape). This manifests itself as tiny
brown flakes that are deposited around your tape transport components. All
recording tape sheds. It is caused by several factors, including the quality
of the tape, age of the tape, the conditions in which the tape has been stored,
how much the tape is handled (how often it is played), how smoothly the tape
transport handles the tape, and the abrasiveness of the various tape transport
components. For example: if your tape machine is out of mechanical alignment
such that the tape scrapes against the reels, you are going to have more shedding
as the bond between the tape baking and the oxide is weakened prior to passing
through the other transport components.
- Shield
- In electronic
terms, a shield is a conductive enclosure, protecting its contents from magnetic
and electrostatic fields. Since audio conductors and circuits tend to be extremely
sensitive to such fields, shields are very important to us! In cabling, shields
often consist of braided copper strands wrapped around the signal conductors.
The amount of coverage the shield provides is directly related to the noise
and hum performance of the cable. Some cables offer a shield consisting of
a thin wrap of metallic sheeting, which can offer complete coverage of the
encased signal conductors. Quality shielding, while more expensive, makes
a tremendous difference in the noise performance of a cable - skimping on
cables is never a good idea!
- Shockmount
- Commonly found
in two places in the audio industry, rack cases and microphone stands, shockmounts
are systems designed to isolate a device mechanically from its stand or case.
In rack cases, the idea is to prevent damage to sensitive gear by isolating
it from shipping and transport bumps, drops and similar catastrophes. Often
these cases consist of a case-within-a-case, with the inner case isolated
with foam or spring arrangements from the outer. Microphone shockmounts are
designed to reject vibrations transmitted through the stand or boom to the
microphone. Several types are in use, one common design using a system of
"rubber-bands" to suspend the mic away from its stand.
- Sibilance
- Sibilance refers
to the high frequency components of certain vocal sounds, especially "s"
and "sh". Sibilance lives in the 5 to 10 kHz frequency range, and
can cause problems if over-emphasized in a recording. While it is possible
to use a graphic or parametric EQ to correct for sibilance, this is often
an unsatisfactory approach. Often the overall track will begin to sound dull
before the sibilance is corrected. A better solution is to use a dedicated
de-esser, or use an EQ in the sidechain input on a compressor to perform de-essing
(see "sidechain" in the inSync Word
For The Day archives for more on this). Since a de-esser dynamically corrects
for sibilance (only processes where necessary), the resulting track
will sound much more natural.
- Sideband
- The result of
one signal or waveform being modulated by another
(or others). When a signal is either frequency modulated (FM) or amplitude
modulated (AM) by another signal sum and difference frequencies are produced
that appear with the signal. These are known as sidebands. The Upper Sidebands
(USB), which are the result of adding the signals together, and Lower Sidebands
(LSB), which are the result of subtracting them. Sidebands are a phenomenon
that occur in FM and AM radio stations, but they are most relevant to us because
they are a phenomenon that occurs in FM Synthesis.
They are a big part of what gives FM synthesizers their unique sound.
- Sidechain
- inSync reader
Shawn E. in Tokyo wonders what a sidechain is, and how it is used - A sidechain
(sometimes called a key input, or a detector input) is a control input used
to trigger a compressor or gate with an external signal. Let's look at a common
example, ducking: When recording voice-overs, the background music bed is
run through a compressor, which is set so that it is not normally operating
on the input signal. The voice-over announcer's mic signal is split so that
it feeds both the mixer's input, and a sidechain input on the compressor.
When the announcer speaks, their voice goes to the sidechain, where it tells
the compressor to start working, turning down the background music. When they
stops speaking, the sidechain tells the compressor to stop working, and the
music comes back to its uncompressed level. Other uses? Try using a kick drum
to trigger a gated bass synth for extremely tight rhythms, or insert an EQ'd
signal into a sidechain, making a compressor more or less sensitive to certain
frequencies (de-essing is a good example of this), many other applications
are possible - feel free to experiment!
- Signal
To Noise Ratio
- In layman's
terms this is simply a measurement of a given noise level in a device as compared
to the level of the signal. Higher numbers signify a greater difference, which
is better. In technical terms it is the ratio of signal power at a reference
point in a circuit to the noise power that would exist if the signal were
removed (its noise floor). The maximum signal to
noise ratio (which in many schools of thought is equivalent to dynamic
range) of a given piece of equipment can be an important thing to know.
This ratio is how much absolute noise it has compared to the highest signal
voltage it can pass without distortion. While signal
to noise ratio is often used as a specification to characterize relative quality
differences in equipment, the way in which measurements must be done, and
the degree to which they can differ, makes the true objectivity of such measurements
highly suspect. Factors such as how much distortion can be allowed before
you say the signal has reached "maximum" as well as other kinds
of noise (like modulation noise) that may only show up when signals are present
are just two examples of many variables that affect objective measurements.
In digital equalizers the signal to noise ratio is a function of the maximum
possible sine wave signal power compared to the
quantization noise (a.k.a. quantization error) power.
This is a very unambiguous value in linear PCM (Pulse
Code Modulation) systems, but in other types of PCM systems the quantization
noise (or quantization error) depends strongly on the level of the audio being
recorded so it is very difficult to nail down the actual signal to noise ratio.
It is sometimes useful to be able to compare S/N Ratio differences between
equipment in certain applications, but it is more important to just understand
the concept. Signal to noise ratio concerns us every time we pass audio (or
video or data) though anything, and knowing what factors in our setup (such
as gain structure) affect it is a fundamental part of building clean, quiet
systems and mixes.
- SIMM
- Acronym for
Single In-line Memory Module. A SIMM is basically a group of memory chips
soldered to a small circuit board designed for easy
installation into computer equipment. These were created to provide some standardization
and ease of user installation for upgradable computers in recent years. The
technology was adopted by musical equipment manufacturers in the 1990's and
now almost all samplers use some kind of standardized memory upgrades (quite
often SIMMs). This provides a more economical means of upgrading memory. SIMMs
are available in different configurations: There are 30 pin and 72 pin versions,
each available in a wide range of memory capacities ranging from 128K all
the way up to 128 MB. There are other more subtle differences between SIMMs
too. Composite versus non-composite arrangements, parity, and many other minor
circuit configuration issues can cause SIMMs to fail to work properly in some
equipment. To say that SIMMs are "standardized" is a very loose
use of the word. Nevertheless, this technology and its scale of economy has
helped to bring the price of memory down by several hundred percent in just
a few years.<
- Sine
Wave
- A continuous,
cyclic waveform in which the amplitude
(or instantaneous voltage) varies according to the sine (a trigonomic function)
of the time. It is unique in that it has no overtones
whatsoever. Since it contains only the fundamental
pitch it gives a smooth rounded tone. Test tones used to calibrate tape machines
and other equipment are generally sine waves. In acoustic instruments a flute
sometimes has a nearly sinusoidal output. On an oscilloscope a sine wave looks
like a symmetrical wavy line.
- Skin
Effect
- The tendency
of high frequency current to travel near the outside of an electric conductor
rather than through its cross section. Skin effect increases the effective
resistance of a wire at higher frequencies. While skin effect is a very important
concern when working at the high frequencies of radio and television, it is
widely considered to be a minor issue at the relatively low frequencies used
in the audio world. There are many audio purists, however, who dispute this
and claim that it still does make a difference.
- Slave
- Our common sense
understanding of the word slave pretty much clues us in to how it is used
in audio/video production. The specific literal definition we are concerned
with is; a machine or component controlled by another machine or component.
When two devices are synchronized to one another it is necessary to have one
be the master and the other the slave. The slave unit responds to commands
or information from the master and is thus controlled by it. This is the basic
principle behind all synchronization in audio and video. For example, if a
computer system is following an analog tape machine (or video deck) it can
be said to be "slaved" to it.
- Slave
Reel
- Historically
refers to a reel of multitrack tape upon which there is a submix of the tracks
from a "master reel" to record overdubs against. The purpose of
slave reels is to more easily provide additional workspace (tracks) for creating
multitrack recordings. Back in the days when sessions began to span across
two 24-track tape machines it was common to record the base tracks from the
first machine as a mix on to the second machine. This allowed the overdubs
to be recorded without having to sync up the two machines (which back then
was a pain) for every pass of the tape. Once the overdubs were recorded using
many tracks on the second machine, they were then mixed and bounced back to
the first reel or were just mixed down to a comp track on the second reel.
Nowadays our modern digital tape machines and disk systems have the ability
to use what are known as virtual tracks (see WFTD archive Virtual
Track) to accomplish almost the same thing.
- Slew
Rate
- Slew rate is
the ability of a piece of audio equipment to reproduce fast changes in amplitude.
Measured in volts per microsecond, this spec is most commonly associated with
amplifiers, but in fact applies to most types of gear. In amplifiers, a low
slew rate "softens" the attack of a signal, "smearing"
the transients and sounding "mushy." Since high frequencies change
in amplitude the fastest, this is where slew rate is most critical. An amp
with a higher slew rate will sound "tighter" and more dynamic to
our ears.
- Slip
Cue
- A DJ trick.
It is a method of cueing up records where the stylus (needle) is placed on
the record at the beginning of the desired material and the record is held
stationary while it slips on the rotating turntable. At the moment of truth,
the record is let go, and almost instantly comes up to the speed of the turntable.
This usually requires a special "slippery" record mat be placed
over the normally rubber surface of the turntable. There are mats made especially
for this.
- Slope
- In audio filters,
slope refers to how quickly frequencies are attenuated by the filter once
the cutoff frequency is passed. Slope is given as a dB/octave figure. For
example in a high pass filter with a cutoff frequency of 4000 Hz, and with
a slope of 6 dB/octave, for each octave (doubling of frequency) above
4000 Hz, the level of frequencies will be diminished by an additional 6 dB.
Slope is determined by the "order" of the filter, or the number
of poles it contains. A first order, or single pole filter will have a slope
of 6 dB/octave. A second order, or two pole filter will have a slope of 12
dB/octave, and so on (slope increases by 6 dB/octave per order or pole).
Creating the
correct slope is very important in filter design. For example, it determines
how accurately an EQ can cut or boost some frequencies without affecting
others. Slope is also important in crossovers, where it is undesirable for
frequencies beyond the cutoff frequency to be passed on to amplifiers and
drivers (typical crossover filter slopes are in the 12-24 dB/octave range).
Sometimes crossovers feature selectable filter slope so that response can
be matched to particular speaker set ups.
- SMDI
- A very interesting
word because it is actually an acronym within an acronym. SMDI, pronounced
"smiddy" stands for SCSI Musical Data
Interchange. SMDI allows samples to be transferred from some sampling keyboards
to a computer equipped with SCSI. The benefit of SMDI over the MIDI sample
dump standard is speed. It can take hours for large samples to transfer
to a computer over MIDI. With SMDI this happens in minutes. In order to do
SMDI data dumps you must have an appropriate software application on the computer,
a SCSI port on both the computer and sampler, and a sampler that is compatible
with the software program. Of course, then there are the other gyrations you
must go through getting the two devices to cooperate with each other on the
SCSI bus.
- SMPTE
- An acronym (pronounced
SIM-tee) for the Society of Motion Picture and Television
Engineers. SMPTE, much like AES (see WFTD archive AES),
IEC, and other organizations, provide a coherent place for keeping professionals
(in this case television and film audio engineers) up to date with current
information as well as formalizing and documenting necessary standards from
time to time. It was SMPTE
who devised the classical method of measuring intermodulation distortion,
but one of their most noteworthy achievements is the formalization and standardization
of SMPTE Time Code.
- SMPTE
Time Code
- SMPTE (see WFTD
archive SMPTE) Time Code (see WFTD archive
Time Code) was an adaptation of the time coding
that was in use by NASA to track space flight. In its current form (as used
by audio and video engineers) it is referenced to video frames and is based
on a 24-hour cycle. Within the 24-hour period each frame is identified by
the exact time with a unique SMPTE address number in hours, minutes, seconds,
and frames (also sub frames can be addressed). The signal is comprised of
80-bit digital words that can be recorded on one track of a video or audio
tape recorder using a modulated (see WFTD archive Modulation)
audio carrier. SMPTE Time Code recorded on analog tape sounds about the same
as the sound your fax or modem makes when transferring data. There are other
types of time code, but SMPTE is now such a standard in the industry that
the words "SMPTE" and "Time Code" are used almost interchangeably.
There are many different variations of SMPTE in use today that we'll eventually
cover here.
- Soft
Clipping
- Clipping is
the "squaring off" of an audio waveform that occurs when the signal
level in a device exceeds that device's capacity to accurately reproduce it.
Soft clipping rounds off the edges of the clipped waveform, making the sound
easier to listen to, and less damaging to high frequency drivers.
- Soft
Knee (Compression)
- A type of compression
where the onset of compression is gradual. In normal or hard knee compression
when the signal reaches the threshold
the unit immediately begins to compress at whatever ratio
is set. In some situations the compression becomes very easy to hear (which
is often not desirable) as the signal amplitude
moves above and below the threshold. This is usually made worse when using
high compression ratios. The solution is to have the compressor gradually
enter into compression at a lower ratio prior to the signal reaching the threshold.
The ratio is gradually ramped up as the signal gets louder until, at some
point beyond the threshold, the full compression ratio is reached. This slower
onset often makes the compression much more difficult to detect. The process
is called "soft knee" because of how the compression ratio looks
when plotted on a graph. In normal compression the knee (which is the point
where compression begins) is an abrupt angle (how steep depends on the ratio)
whereas in soft knee it is more of a curve.
- Solder
- A metallic alloy
used to seal joints. In plumbing solder is used to seal metal pipes, in electronics
it is used to electrically and mechanically join components together. For
example, this is what is used to affix components to an electronic circuit
board. Plumbing solder and electronic solder cannot be used interchangeably
as they are comprised of different materials. At room temperature solder is
a solid metal, but when heated by a "soldering iron" or some other
heat source it becomes liquid. In fact, it very suddenly becomes liquid. It
doesn't go through much of a "soft" stage at all, which is one of
its desirable properties. To solder (verb) is the process of heating solder
and using it to join materials. Once it cools it very quickly becomes a solid
metal again and provides (when done correctly) a strong electrical and mechanical
joint.
- Solo
- A function commonly
found on mixing consoles, soloing a channel is the opposite of pushing a mute
switch; solo mutes all channels EXCEPT the one being soloed. In general, solo
only affects signals in the control room monitors, or headphones on a live
console. It does not mute signal being sent out other outputs. This allows
the engineer to listen to individual signals while not interfering with other
mixer functions (feeding recorders or PA amplifiers, etc.).
- Song
Position Pointer (SPP)
- A type of MIDI
message held in a MIDI sequencer or synchronizer telling a connected device
how many 16th notes have elapsed since the beginning of a song. Used in conjunction
with MIDI clocks, this allows operation similar to true time code (which
provides location as well as speed information). Song Position Pointer
is used by sequencers and synchronizers which do not support MIDI
Time Code (MTC) or SMPTE time code as a means
of locating to a point in a song other than the beginning or the end. For
example, a sequencer synched to a tape deck can use Song Position Pointer
to start at the correct bar and beat even if the deck hasn't been rewound
to the beginning of the song, or has been fast-forwarded from where it was
stopped.
- Sound
Pressure Level (SPL)
- The acoustic
volume or loudness of sound, measured in decibels. SPL is a function of a
signal's amplitude. Aside from the usual (and justified) warnings about
hearing damage from high SPLs, it is worth noting that because of the way
our ears function, sounds will appear to have a different timbre (or tone)
to us at different SPL levels. This is important to keep in mind, especially
when mixing in a studio environment. Be sure to check your mixes at a variety
of volume levels to ensure that the mix is accurate. The old rule of thumb
is that if a mix sounds good at a low SPL, it will sound great at higher
levels...
- Soundstage
- Typically known
as a room or studio, usually soundproof, where audio production for film and
video is done. It has also become a word occasionally used to describe the
virtual acoustic space produced in a recording or sound playback system. When
you listen to a CD of an orchestra and you can tangibly hear the acoustic
space of the recording and where the instruments are in it, the created space
or sonic signature is known as the sound stage.
- Spaced
Omni
- A method of
stereo recording where two omnidirectional microphones are placed several
feet apart in front of the sound source. This system was used by Harvey
Fletcher in 1933 in the first demonstration of stereophonic reproduction
of an orchestra. Because the omni pattern will pick up room ambience as well
as the desired sound source, mic placement is critical in balancing room sound
with direct sound. And, as with any stereo miking technique, phase must also
be considered when placing the mics. Spaced omnis are excellent where a natural,
"real" sound is desired.
- S/PDIF
- A format for
interfacing digital audio equipment together, S/PDIF (Sony/Philips
Digital Interface Format) is considered a consumer format,
and is largely based on the AES/EBU standard. In fact, in many cases the two
are compatible. There are, however differences between the two formats, particularly
in the channel status and user bits.
S/PDIF typically
uses either unbalanced, high impedance coaxial cables or fiber optic cables
for transmission. When using coaxial cables for transmission, it is normally
best to keep cable lengths to a minimum, and to use the best quality 75
ohm video-type cables available.
- Speakon
- A type (and
brand) of multi-pin connector developed by Neutrik which is now commonly
found on speakers and amplifiers intended to be used in high power mobile
applications. They have become popular because they offer a very high quality
reliable connection, can handle extremely high power, are very durable, and
are relatively low cost compared to other similar connectors. Standard Speakon
connectors come in four or eight conductor versions (though other configurations
are available). The Speakon 8 has the same footprint as the EP8 connector
and the Speakon 4 has the same footprint as XLR "D" type connectors.
- Splatter
- An onomatopoeia
(word that sounds like what it is). A type of extreme distortion in an audio
signal caused by hard clipping of the waveform from
a device being overloaded. As mentioned above, the word splatter pretty well
gets across what it sounds like. While it can happen in all sorts of audio
devices the use of the word comes mostly from distortion caused by overmodulation
in AM transmitters where splatter has additional implications.
- Standing
Wave
- A phenomenon
where a sound is reflected back and forth between two parallel surfaces, such
as two side walls in a room. Technically they are created by "room modes"
or "eigentones," which are modes of vibration of air in the room.
The sound waves interfere with one another to produce a series of places where
the sound pressure level (SPL) at some frequencies
is high, and another series of places where they are low. The places are sometimes
called peaks and nodes. A standing wave exists in a room where a frequency
is such that the distance between any two surfaces is equal to one half of
its wavelength.
For a given distance there will be many frequencies that will generate standing
waves, each a multiple of the fundamental frequency
whose wavelength is related to the dimension in question. Standing waves are
always detrimental to the acoustics of a room, but can be avoided by careful
room design, or minimized by absorbing the frequencies where they build up,
which is usually along walls or in corners.
- Standard
MIDI File (SMF)
- A standardized
file format for saving MIDI sequences independent of the platform they were
created on. Standard MIDI Files allow musicians with completely different
types of computers or sequencers to exchange MIDI sequences. There are two
types, Type 0 (single track), and Type 1 (multitrack). Each
type contains the same information, but on a Type 0 all MIDI channels are
combined into one track (MIDI channel assignments and other information
are not lost) while on a Type 1 each track is kept separate.
- Star
Ground
- A type of grounding
scheme used in some studios to prevent ground loops.
It requires isolating each piece of gear from AC
ground (using a ground lift adapter) and running
a separate ground wire from the chassis of each piece (including the racks
themselves) back to the main studio ground (we call this "Technical Earth").
This "Tech Earth" gets connected back to a main AC ground, and/or
a large copper rod driven 18 feet into the ground. Thus every piece of gear
still has AC fault protection, but no earth grounds are tied together. Technically
limited ground loops can still exist in the studio signal wiring, but the
path length differences are minimized to an extent that it isn't likely to
be a problem. Star Grounding is a time consuming and complex wiring scheme,
but is generally very effective at preventing ground loops and works great
in conjunction with other measures such as telescoping
shields. Occasionally you'll still find some piece of gear that requires
audio transformers to eliminate ground loops. Generally you'll find that with
today's equipment, you really don't have to go as far as all this. Telescoping
shields, balanced lines, and careful consideration
to signal cable wiring with today's equipment is often good enough.
- Stopband
- The frequency
range attenuated or not passed by a filter is called its stopband (as opposed
to its passband, where signal is let through unprocessed). A filter can have
more than one stopband. For example, a bandpass filter has a passband with
a high stopband above it, and a low stopband below it.
- Strap
- In audio this
term usually applies to multing two signal paths together. It is often specifically
used in patch-bay jargon and means to connect two patch points together for
the sake of making a common signal connection. Straps are typically used to
connect a top and bottom patchbay jack's normal switches for normalling. The
way you strap the normalling switches determines whether a patchbay is configured
as normalled or half normalled.
These straps are a built-in, hidden feature of many commercially available
"plug-and-play" patch bays. Sometimes the user can reconfigure them,
often by moving jumpers inside the patch bay. In professional custom installations,
however, the individual straps (normals) must be wired by hand just like the
rest of the patch bay.
- Stripe
- Besides its
obvious other uses the word stripe is commonly used in audio to denote the
recording of time code onto a tape. Typically (and this was especially true
in the analog days) time code was recorded onto
the entire length of one track of tape in one pass. Thus the verb to "stripe"
a tape came into wide spread use. Nowadays, with our digital and non-linear
systems, it is often not necessary to stripe time code because these systems
have built in coding that can be used as a good timing reference and converted
to SMPTE when needed.
- Subcode
- On digital media,
there is a region of the tape where audio data is not recorded. Rather, this
area has subcode written to it. Subcode can consist of a variety of different
types of non-audio information; track number, indexing, and timing information
such as track length and elapsed time, is found there. Digital tape has a
higher capacity for subcode information, and such proprietary information
as text (song titles), timecode, or even picture can be found written to subcode.
- Supraaural
- Used in reference
to headphones. Supraaural phones rest "on the ear", rather than
enclosing the ear. Supraaural phones typically are lightweight, and because
they do not seal around the ear, tend to not provide good isolation.
- Supercardioid
- A polar pattern
name used to describe the pickup pattern of some microphones. The supercardioid
pattern is very similar to, and often confused with, the hypercardioid
pattern. The supercardioid pattern is slightly less directional than the hypercardioid
pattern, but the rear lobe of sensitivity is also much smaller in the supercardioid.
- Surface
Mount
- In electronics,
a generic name for miniature components that are entirely mounted to the surface
of a circuit board. Historically electronic components had little legs, called
leads, that protruded through holes in the circuit board. Solder was applied
from the backside to hold them in place and make electrical connection. As
electronic parts became smaller and smaller it became more efficient to just
mount the component to the front surface of the circuit. These components
usually rest entirely on the circuit board with contacts at the leads on the
component soldered directly to the top of the board. Besides making things
more compact, it also makes it even easier for modern machinery to build high-density
circuits with more efficiency, thus lowering the price of equipment to the
end user. The only downside to SM components is that they are harder to replace
in the field. Precision soldering/desoldering equipment and a very steady
hand is required. Often a magnifying lens must be used. Most electronic equipment
you buy today is made predominantly with surface mount components.
- Sustained
Transfer Rate
- This spec details
the speed at which a drive sends and receives data. Sustained transfer rate
is the total time required for system processing, head switching, and seek.
This spec is the most accurate reflection of a drive's true, real world performance.
Be careful when comparing drives; in many cases, manufacturers will only display
their drive's burst transfer rate, or maximum transfer rate (a much higher
figure reflecting only the movement of data into RAM). While this is a useful
spec for many applications, it does not reflect the requirements of digital
audio or video.
- Synchronization
- In keeping with
the release of the Digital Time Piece, our word for today is "synchronization."
In audio terms, synchronizing, or synching, is the process of making two devices
operate together as one. One device will be the "master", and tell
the second "slave" device when to start, when to stop, and how fast
to play. Originally, synching devices primarily meant locking two multitrack
tape recorders together to allow for more tracks, or locking audio and video
decks together when adding sound to picture. Today, synchronization also encompasses
locking recorders to computers, various digital devices' clocks to each other,
MIDI to SMPTE, and a variety of other possibilities. Synchronizing wildly
different technologies together can be a complex process; having a central
master sync device like the DTP around can definitely make life much easier!
- Syquest
- Syquest
is a company most noted for making affordable volume removable storage media
and related drives for computer systems. They were so popular in the early
1990's that their name became synonymous with the removable hard drive cartridge
to the extent that it is sometimes used as a generic name for them (which
also elevates its stature to being worthy of an inSync
Word for the
Day). Early Syquest drives and media were 44 Megabytes.
Later they updated to 88 MB drives, and then on to 105 and larger sizes. SyQuest
filed a Chapter 11 petition with the United States Bankruptcy Court in Oakland,
California on November 17, 1998. Trading in SyQuest stock was suspended on
November 2, 1998. Their assets are currently being sold to Iomega, another
company known for its removable media.
- System
Exclusive
- One of the categories
of MIDI messages, System Exclusive (Sys Ex) is data intended for, and understood
by, only one particular piece of gear. Normally, this data is used to communicate
with and control parameters specific to that item. For example, all of the
proprietary data in a Roland D-110 synthesizer representing RAM patches might
be sent as a "sys ex dump" to a computer librarian. When the computer
sends this data back out over MIDI, the only device recognizing and responding
to it will be a D-110, all other synths and MIDI devices will ignore it. Other
uses for sys ex? MIDI control of parameters not supported by continuous controllers,
remote patch editing, patch bank select, and more - uses depend on, and can
be tailored for, each specific piece of MIDI gear - that's the beauty of sys
ex!
- System
Real Time
- One of the MIDI
System messages (another is System Exclusive). System real time messages are
a set of messages that serve as uniform timing information for the synchronization
of MIDI equipment. They are sometimes just referred to as Real Time Messages.
Because of the timing-critical nature, a system real-time byte can be inserted
into the middle of any multi-byte MIDI message. System real-time messages
include MIDI clock, start, stop, continue, active
sensing, and system reset.