Audio Engineering Final Study Guide

Sound is a disturbance of mechanical energy that propagates through matter as a:

Longitudinal Wave

A single complete cycle of an acoustical pressure wave consists on half-cycles of _____ followed by one half cycle of ______.

Compressions/Rarefaction

What term is used to refer to the rate of air pressure fluctuation?

Frequency

What term is used to refer to the amount of pressure variation?

Amplitude

What physical property of sound provides the pitch in a musical instrument?

Frequency

The position of a sound wave in its cycle at a given point in time or in relationship to another one is called:

Phase

The acoustical envelope of a sound can be broken down into these sections:

A (Attack) D (Delay) S (Sustain) R (Release)

The Harmonic Content can be described musically as:

Timbre

What number system is used by digital systems to encode audio?

Binary

The Nyquist Theorem says that the _____ needs to be _____ as high as the highest recorded frequency.

Sample Rate/Twice

How are the number of measurements that are taken in 1 second called in digital audio?

Sample rate

The number of levels (values) that represent one sample are known as:

Resolution

Bit depth has a direct effect on:

Dynamic Range

Sampling rate has a direct effect on:

Latency

What is a DAW?

Digital Audio Workstation

In a digital audio system, what device is in charge of the sampling and quantization processes?

AD/DA Converters

The difference between the loudest and the softest levels a system can handle is known as:

Dynamic Range

A device capable of converting one type of energy into another is called a:

Transducer

What do engineers refer to as the “brains of the studio”?

The patchbay

This type of patch connection will break the input but not the output path

Half-Normaled

What is the most widely use of patch connector in professional recording studios?

TTY

What is currently the most widely use connector in studios for multi-channel audio cables (aka Snakes)

DIN

How many individual cables can be found inside a CAT6 cable?

8

How many individual cables can be found inside a USB-A cable

4

How many individual cables can be found inside a MIDI cable

5

How many individual cables can be found inside an XLR cable?

3

A female connector that can accept either TR, TRS, or XLR is called a:

Combo Jack

(T/F) MIDI cables carry both, data and audio

False

(T/F) The quality and materials of an analog cable have an effect on frequency response.

True

(T/F) The quality and materials of a digital audio cable have an effect on frequency response

False

Network cables can carry MIDI, analog and digital audio

True

The standard format for CD audio is:

44.1kHz/16 bit

The two operations done by an AD converter to digitalize audio are:

Sampling and Quantization

The signal paths used to send signal laterally from one channel to another channel are called:

Buss

The signal paths used to carry the signal from the input into the Mix buss on a console is called a:

Channel

The signal path where multiple audio signals are combined are routed together is called a(n):

Buss

The process of converting one type of acoustical energy into another is called:

Transduction

The slope parameter in filters and EQ bands is typically measured in:

dB/Octave

The type of EQ with fixed bandwidth, fixed frequencies and multiple faders each controlling a frequency band is called a:

Graphic EQ - only one with faders

The type of EQ with selectable bandwidth, frequencies and Q is called:

Paragraphic EQ

The difference between the loudest and the softest levels a system can handle is known as: (REPEAT?)

Dynamic Range

The difference between nominal level and noise floor is called:

Signal to Noise Ratio

An expander with a ratio of 10:1 or higher is known as:

Gate

A compressor with a ration of 10:1 is known as:

Limiter

What compressor parameters defines how smooth the transition between compressed and non-compressed signal should be:

Knee

Which compressor parameter defines the signal level at which the unit starts engaging?

Threshold

Name 10 essential tools an Audio Engineer should have when on the job

• Multitool

• Flashlight

• Tape

• Sharpie

• Zip Ties

• Headphones

• Wire Tester

• Gloves

• Adapters

• Saudering Kit

What are the three types of electrical analog audio signal running through an audio system

Line Level, Mic Level, Speaker Level

What are the two types of line signals and their respective levels

Consumer (-10), Pro (+4)

What are the two types of electrical audio formats in an audio system

Analog and Digital

Name five types of audio input transducers

• Microphones

• Instrument Pick Up

• Needle on Vinyls

• Tape Head/Playback Head

• Electromagnetic pick up

Name 4 types of audio output transducers

• Speakers (Woofer, Sub-Woofer, Subtweeter, Midrange)

• Recorder Head

• Recorder Needle

What is an octave?

A unit for ratios between frequencies (Doubled to be an octave)

What is phase?

Time relationship to another sound wave

What is frequency response?

The usable range of frequencies that pass from input to output/The highest and lowest frequencies the human ear can hear (20-20,000 Hz)

Define the four musical properties of sound:

Volume - Amplitude

Notes - Frequencies

Timbre - Harmonic Content

Acoustical Envelope - ?

Define distortion in an audio system

Frequencies that exist at the output that weren’t at the input

What is the approximate frequency response of the human ear?

20-20k Hz / 20-120 dBspl

What are the most commonly used Sample Rates in pro audio?

44.1 kH, 48 kH, 96, kH, 192 kH

What are the most commonly used bit depths in pro audio?

16 bit, 24 bit, 32 bit, 32 bit float

What are the most common file formats in audio?

Compressed (.Mp3) and Uncompressed (.WAV or .AIFF)

Name the Digital Audio formats most used in professional audio for data transmission.

.WAV, .MP3, .AAF

What is an STP cable? Can it pass phantom power?

Shielded Twisted Pair cable, YES because it is shielded

What are the three most commonly used kinds of built-in connections between patch points?

Normal, Half-Normal, Mult

What is a balanced cable?

When a cable has positive, negative, and ground conductors. All balanced cables are shielded.

What is the name of the cable-connector most commonly used in professional patchbays?

TTY (TeleType Writer)

What is a Mix Buss?

The bus that combines al the signals inputed into the board or console

What is the difference between Pre-Fader and Post-Fader on a channel strip signal path? What is each most commonly used for?

Pre-Fader: Routed before it gets to the fader. Commonly used for effects such as reverb. Won’t be affected by the Main Channel Fader

Poster Fader: Routed after it gets to the fader. Commonly used for compressors and limiters. Will be affected by the Main Channel Fader

What is a Tie Line?

It is a patch in the wall with inputs and outputs which connect audio to different rooms

What is an Insert? What is it typically used for?

It is another output to input used with a Y cable. It is used for outboard/external gear not attached to the board/console. Recommended for dynamic effects (Effects you want to use with 100% effectiveness)

What is the approximate dynamic range of the human ear?

20-120 dB spl

What is a dB?

Measurement of two ratios between two quantities often related to power. Measured by 1/10th of a bell created by Alexander Graham Bell

Why is audio level measured in dBs?

Because it needs to know what is referencing, whether acoustical or electrical

Name 3 dB types used to measure electrical signal:

dBm (mic level), dBu (Line level), dBV (speakers)

Name 2 types of dB used to measure acoustical levels:

dB SPL, dB PWL

Explain the equal loudness Contour phenomenon as described by Fletcher and Munson

The human ear is sensitive to different frequencies therefore naturally sounding louder than others

What is Dynamic Range

The difference between the loudest and the softest sound in a system.

What are the names of the two main level sections and the three reference levels in a systems dynamic range?

Reference LevelsNoise Floor, Nominal Level, Ceiling

Level Sections: Headroom, S/N Ratio

What are some of the limiting factors defining the ceiling on a live sound system?

Limited by design and components of gear and quality of other gear.

What are some of the of the limiting factors defining the floor on a studio sound system?

Every component has noise, so it depends on the quality of the gear.

According to the book, what is a microphone?

Any element that transforms acoustic energy into electrical energy

Name 5 types of mircrophones based on their methods of transduction

Dynamic Mics, Condenser Mics, Electret Condenser, Ribbons, Carbon

Name 8 types of microphones based on their functional design

Hand Held, Stand Mounting, Contact Pick Up, Pressure response, Shot Gun, Parabolic, Lavalier

Name 4 pick up patterns used by microphones

Hyper Cardioid, Super Cardioid, Bi-directional, Omnidirectional

Briefly explain the proximity effect

The closer you get to the mic, the more bass responds and gets augmented based on proximity. (Ribbon is the only one without proximity effect)

What does the sensitivity spec for a mircrophone indicate?

It’s the maximum pressure level the mic can take

What is the purpose of a shock mount?

Decouples the mic from the floor from picking up other vibrations

What is phantom power and what is it used for?

It is an electrical current sent straight through the XLR cable to power the mic (Specifically condensers most of the time) Without it the mic won’t work. If used with some mics it could blow them up.

What are the two most commonly used phantom power types?

48v and 24v (12v)

What is a patchbay?

The brains of the studio. Connects all the external gear into the board.

What is DANTE

Digital Audio Network Through Ethernet (Network system formed out of software, firmware, hardware, and protocol)

What is an IP address and what are the two types of IP addresses?

IP = Internet Protocol

IPv4 - 4 groups of #’s separated by periods

IPv6 - 8 groups of hexadecimal numbers

What is a DVS?

Dante Virtual Soundcard

What is DANTE via?

software that delivers multi-channel routing of computer-based audio

What are the benefits of using DANTE over an analog audio system?

You can connect a whole campus to one network and control from one room to different rooms

What are the cons of using DANTE?

All of your tech has to run DANTE?

What is a PoE?

Power over Ethernet

What are the different wattage powers for PoE, PoE+ and PoE ++?

PoE - 15.4 watts (Suitable for devices with low power requirements)

PoE+ - 25.5 watts (Devices with high power like PanTiltZoom cameras - security cameras)

PoE++ - Type 3 (60 watts) & Type 4 (100 watts)

Review all types of audio connectors

• Speakon

• Female ¼ TRS/TRRS/TS (Balanced and amount of rings)

• BNC Cable for world clock

• RCA

• DN (MIDI) Connector

• 5 Pin XLR not for audio but for lighting

• 8 Pin Speakon

• Ethernet (CAT 5,6)

• USB A
  USB B

• USB C