audio exam Flashcards
How do we measure the level of sound?
Decibel
The human hearing responds to a broad range?
Frequencies
What is the standard ratio band for professional analysis EQ?
31 band EQ
What is the range of the human audio spectrum?
20Hz – 20,000Hz
How many octave bands are in the above audio spectrum?
11octave bands
What do we often talk about frequencies as?
Ratios
What do we define average threshold of human hearing?
1kHz – 0dB SPL
What dB scale is the threshold of pain?
120-130dB
What does logarithmic scales express?
Loudness in non linear as a compact form as decibels
Can decibel measure voltage?
Yes
What are critical bands?
The smallest frequency difference between two signals or partials such that each can still be heard separately.
What are the three sections of the ear?
Outa, Middle, Inner
What the other name for the outa ear?
Pinna
When sound focuses into the ear canal what is the level of db boost?
5 to 6dB boost
What’s the function of the tympanic membrane?
The tympanic membrane converts acoustic pressure variations from the outside world into mechanical vibrations in the middle ear.
What are three auditory ossicles of the middle ear?
Malleus, Incus, Stapes
The inner ear consists of the snail-like structure what is its name?
Cochlea
What is the function of the cochlea?
The function of the cochlea is to convert mechanical
vibrations into nerve firings to be processed eventually by the brain.
Which way do we recognise sound in the cochlea?
High frequency to Low frequency
What’s the medium frequency in the cochlea?
1.5kHz or 1,500 Hz
What does the basilar membrane do?
The basilar membrane is responsible for carrying out a frequency analysis of input sounds.
What does MIDI stand for?
Musical Instrument Digital Interface
What does MIDI Do?
A communications language that lets synthesizers, computers, keyboards, controllers and other devices talk to each other.
What a three ports of MIDI?
MIDI in, MIDI out, MIDI thru
What is another connectivity with todays hardware devices?
USB (Universal Series Bus)
Name four various MIDI messages?
Note on, Note off, controller change, pitch bend
MIDI cable carries how many logical channels?
16
What is a MIDI Network?
A MIDI network is a combination of hardware and software that provides interconnectivity between a group of MIDI devices, such as
synthesizers, controllers, and sequencers
How many bits per second of a MIDI data rate?
31250 bits per second
- Can MIDI handle 1500 messages per second?
Yes
Name two types of MIDI bytes in a message?
Status, Data
What’s the meaning of a control or controller?
An instrument that controls other, (keyboard controller, etc.) Physical controls (foot pedal etc.) MIDI control change messages [volume controller etc)
What are the four types of MIDI messages?
Channel Messages/System Exclusive Messages/System Common Messages/System Real-Time Messages
What’s a synthesizer?
A synthesizer is an electronic musical instrument that uses one or more sound generators to create waveforms which are then processed and combined in order to generate musical sounds
What’s the application of a sequencer?
A music sequencer is an application or a device to record and playback musical information / notation
What’s a sampler device?
A sampler is an electronic musical instrument which plays back recordings (or “samples”) that are loaded or recorded onto it to perform or compose music
What is General MIDI?
General MIDI or GM is a standardized specification for electronic musical instruments that respond to MIDI messages.
Name one non musical application that MIDI could be used for?
Special effects, Lighting etc
What is a transducer?
A transducer is a device that coverts energy from one form to another. Usually a transducer converts a signal in one form of
energy to a signal in another. Types of transducers you’ll be using are microphones and loudspeakers
Does a microphone have a transducer?
Yes
. What is amplification of sound?
Amplification of sound involves input and output transducers (usually a microphone and loudspeaker).
What kind of devices would you find a vacuum tube?
Guitar Amplification, Some hammond organs, HIFI, certain recording equipment, microphones,
old vinyl amplification etc
What a the four ways of storing the electrical signals of captured sound?
Vinyl, Magnetic Tape, Compact Disk, Digital Recording
. What are the four components of recording to vinyl?
Cylinder, Needle, Diaphragm, Horn
Vinyl records revolve at?
33 or 45rpm
What kind of cut into a vinyl LP would produce 4 tracks of 300Hz?
Vertical
What type of recording machine produces AC bias?
Tape Recording Machine
How many heads did a tape recording machine have
3- Erase head, record head, playback head
What are three most common microphone types?
Dynamic, Condenser, Ribbon
Which microphone type would be best for a live performance?
A dynamic microphone
Name two disadvantages with a condenser microphone?
Expensive, May pop and crack closed miked (fragile)
Name two microphone directivity?
Omnidirectional, cardioid
Name four parts of a dynamic speaker?
Suspension, cone, magnet, diaphragm
Name the three parts of a three-way speaker?
High frequency driver, Mid frequency driver, Low mid/Low frequency driver
What is binaural hearing?
Binaural hearing gives a sense of localization of the sound source
. What’s non linear gain?
Overdriving an amplifier occurs when the amp is supplied with an input signal that takes it outside its linear region
. Name one of the limitations of amplification?
Limited output voltage, current, and power levels. This will mean that a given amplifier can’t output
signals above a particular level.
What does SNR stand for?
Signal to Noise Ratio
. What does Panning on mixing desk do?
Changes the placement of the signal
What are the 5 digital representations of sound?
Sampling, AD/CA DAC, Sampling rate, Quantization, Resolution
What is a sample rate?
The numbers of samples per second is the sample rate
What does ADC and DAC stand for?
Analogue to Digital Converter/Digital to Analogue Converter
When does aliasing or foldover occur?
Aliasing or Foldover occurs if you try to digitise a signal higher than the Nyquist frequency?
What is the common sample rate for CD audio?
44.1kHz
What does the sample rate need to be to achieve the Nyquist frequency?
The sampling rate must be at least twice as high as the highest frequency to be reproduced
What is quantization?
Is assigning binary values to analog inputs
How many bits are in CD audio
16 bit
Name one process of a computers memory and storage?
RAM or CPU
What is dithering?
Introduces random noise into the signal to spread out the effects of quantization distortion replacing it with 1b noise and making it much less noticeable
True or False – Digital Clipping produces a good unity range?
False
What would +4dBu level be in digital (full scale)?
-20dbFS
A perceived doubling of the apparent volume is an increase of approximately: +
+10dB
An average perceptible halving of the volume of a sound is a change in level of
-10dB
Name three uncompressed file formats?
WAV, AIFF, CAF
What is the most popular lossy compressed file to send by email?
MP3
Name three advantages to digital?
Wider Dynamic Range, Better reproduction, Time Efficient
Name one disadvantage?
Clipping
Can a clipped recording be restored?
No, re-record
