 | AGC Automatic Gain Control set the sound levels for you. |
| Aggregators are pieces of software that allow websites to be
regularly checked for updates. They need the RSS standard and allow
users to 'pull' news rather than wait until it is 'pushed' at them. |
| Analogue describes the type of signal which is, as the word
suggest, analogous to the source. In other words, the signals looks the way
it did when it left the source. The alternative to analogue (or analogue as it
is rendered in the US) is digital. The irony is that the analogue which
contains all the information , has been displaced by digital sampling.
However, when the sound is delivered to the listener must be an analogue of
the original. |
| ADC (analogue-digital-converter) converts the analogue
sound-signals we can hear into a digital format that we can process and store
on a computer. |
| Breakout box often mounted in a drive bay to house audio and video
connections. |
| Buffering is a process where some seconds worth of material are
kept in reserve to allow for the intermittent delivery of data. The player
requests the next segment when the buffer runs low. |
| Cans aka headphones but not of the earplug variety. |
| Clipping occurs when the sound wave exceeds the amplitude the electronics
can cope with. (i.e. It is too loud). |
| Compression schemes include, MPEG 1 Layer 3 (MP3), Advanced
Audio Coding (AAC), Adaptive Transform Acoustic Coding (ATRAC
used in MiniDisc), and Windows Media Audio (WMA). |
| Critical Distance (Dc) is a distance in every room, measured from
the source, where the direct and the reflected speech are equal. Anybody not
at the critical distance will hear two or more versions of the same sound. |
| CD quality is created when two 16 bits samples are taken 44,100
times per second. = 2x16x44100 bits per second of music or 176,000 bytes per
second. |
| DAC (digital-analogue-converter) restores an audible, analogue signal from the
digital sample. |
| DAT (Digital Audio Tape) audio processing device allows the
transfer of audio from one file to another without the conversion to and from
an analogue format, which could degrade the signal quality. |
| Digital Signal Processor (DSP) is a specialized microprocessor and
takes some of the workload off of the computer's CPU |
| Dynamic range is a function of pieces of acoustic equipment. |
| Equalisation is a way that the electronics compensates for the way
that different media stores sound. |
| Envelope is the term applied to the outline of a wave's shape. |
| Feedback is better expressed as acoustic feedback, occurs when the
amplified sound from a loudspeaker re-enters the sound system through any open
microphone so is amplified again and again. A nuclear chain reaction is
feedback but happens much faster. The quick solution is to turn off mics when
not in use and/or shield them from the amplifiers. |
| FireWire /
IEEE 1394 connects video recorders. |
| Foley artists supply the subtle sounds that production mikes often
miss during post-production. |
| Frequency is a physical measurement of vibration per second |
| Frequency Response The audible range of the human ear is
approximately 20 Hz to 20 kHz. The most important frequencies for speech occur
between 250 Hz and 8 kHz. Telephone line frequencies are limited to those
between 400 Hz and 3.4 kHz. |
| Gain has a meaning that is very similar to volume when referring to
audio. |
| Hum or more accurately, mains hum, is the sound produced when the
50 or 60 cycles per second note that is used by the electrical distribution
system intrudes into the detection or amplification system. Good grounding is
normally the answer. |
| MIDI (Musical Instrument Digital Interface) synthesizers musical
instruments in a computer. |
| PCM Pulse Code Modulation is the process used to overlay
information on top of an analogue wave. |
| Pitch is a subjective quality perceived by the human ear. Often
defined by 'highness' or 'lowness' of a note. |
| Podcasting the emerging meaning is
downloadable broadcast on demand. |
| Pop-filter is a screen that removes the high energy sounds such as
P, T B and S. |
| Pre-amp(lifier) is an underrated piece of electronics that turns
the minute input signal into something the amplifier can work on. The preamp
performs many other technical tricks to ensure the signal accurately reflects
the wave pattern going in without injecting miscellaneous noises. |
| Impedance is an electrical characteristic similar to resistance and
affects how much of a signal is transferred to the sound card. The output
impedance of a microphone must be less than the input impedance of the sound
card. |
| Level is a general term to indicate the ‘size’ or ‘strength’ of a
signal. |
| MIDI (Musical Instrument Digital
Interface) specification defines a physical connector, message
and storage format for connecting and controlling devices that generate
musical instruments. |
| MP3 format is a compression system for music by a factor of 10 to
14 without noticeably affecting the CD-quality sound. A 32MB song on CD
compresses to about 3 MB. The technique works because there are some
frequencies that the human ear cannot hear and others it hears much better.
Also when two sounds are playing simultaneously only the louder one is heard.
|
| MPEG is the acronym for Moving Picture Experts Group that developed
compression systems for video data used in DVDs. One subsystem to compress
sound, called MPEG audio Layer-3 which we know as MP3. |
| Normalization brings the overall volume level up to exploit the
recording technology |
| Podcasting (Pod was the name given to the iconic MP3 payer from Apple) |
| Resistance is measured in ohms (Ω
) and is a measure of the amount of electrical resistance something puts up.
Think of a water hose. A very thin hose puts up lots of resistance so not a
lot will get through. Attach a pipe and you will drain the tank in an instant.
Now reverse the process in your mind. The thin hose will not feed enough in,
while the big pipe will cause everything to get covered in water. The
electrical equivalent is an expensive puff of blue smoke. The message is that
resistance of whatever you are plugging in needs to match the design of the
output. |
| Reverberation happens in an enclosed space when multiple
reflections build up and blend together. |
| RSS technology allows Internet users to subscribe to websites and
receive notice of changes. To achieve this site owners use an emerging XML
dialect that enables the headlines to be scanned for items of interest. |
| Tape hiss is a characteristic magnetic tapes which gets amplified
along with the signal stored on the tape. Noise can drown soft passages.
Digital recording technique avoid this. |
| Signal to noise ratio is a measure of amount of white noise
generated by the electronics. |
| Sampling rate measures the number of samples taken of an analogue
signal and is measured in kHz. The faster the rate, the more accurate the
stored image of the wave is. |
| Streaming is one method of sending audio or video and is
effectively 'live' broadcasting. The data stream is not stored but is played
as it is sent. See buffering and podcasting |
| Rip(ing) is a process of converting music tracks from a CD to an
MP3 file. |
| RCA connector is a coaxial plug sometimes known as a phono and jack
plug. |
| S/PDIF (Sony/Philips Digital Interface) is the standard file
transfer protocol for digital audio data. Uses RCA coaxial or optical
connections. |
| VU (Volume unit) meter displays the average volume level of an
audio signal. A PPM displays the peak volume level of an audio signal. |
| Webcasting is just like broadcasting but uses the web rather than
radio-signals and the ether as the conduit to deliver material. |
| White noise is low level fizz that is produced by the amplification
of the random motion that happens in every piece of electronics (above
absolute zero). Designers have done their very best to eliminate it form
recording equipment. |
| Wild track is the background sound that can be applied at the
editing stage to give an interview context. You might have the sound of wind
blowing through trees to open a scene and then fade it to the background once
the reading starts. |
