Recording Systems 2 Study Guide

Standard sample rates for: Professional video / broadcast

44 kHz

Standard sample rates for: Compact Disc

44.1 kHz

Nyquist Shannon Theorem

in order to accurately reproduce a signal, it should be periodically sampled at a rate at least TWICE the highest frequency recorded

Effects of higher sample rates

• provide wider frequency response

• reduce aliasing distortion during heavy plugin processing

• requires more CPU power

• smoothes out higher frequencies

What is PCM

the standard method for converting analog audio into uncompressed, high-fidelity digital audio

Lossless audio format

a digital file format that compresses audio without losing any original data, ensuring the playback is identical to the source master.

Lossy audio format

a digital audio compression method that permanently eliminates, or "loses," data considered less audible to human hearing to drastically reduce file sizes

Core Audio

the foundational digital audio infrastructure for Apple’s operating systems (macOS, iOS, iPadOS, tvOS, and watchOS). It acts as the intermediary between audio applications (like GarageBand or Spotify) and the hardware, handling low-latency, high-resolution audio input/output, processing, and recording

Common plugin formats used in OSX/iOS

1. Audio Units

2. VST

3. AAX

What is Latency

the time delay between producing a sound and hearing it, typically measured in milliseconds (ms). It is caused by digital processing (A/D/A conversion, buffering) or physical distance. Common synonyms include lag, delay, and buffer delay and causes audible echo or "out-of-sync" issues.

How does Buffer Size affect latency?

Lower→minimizes

Higher→more

Tracking Buffer Size

Low

minimize latency

Mixdown Buffer Size

High

maximize CPU resources

What MIDI stands for

Musical Instrument Digital Interface

5 MIDI Pins

1. nothing

2. ground

3. nothing

4. signal

5. signal

MIDI In

recieves messages from an external source and communicates this performance, control and timing data to the device’s internal mircoprocessor, allowing an instrument to be played or a device to be controlled

MIDI Out

used to transmit MIDI performance, control messages or SysEx data from one device to another MIDI instrument or device

MIDI Thru

retransmits an exact copy of the data that’s being recieved at the MIDI In jack

MIDI channels per device

16

MIDI “magic number” (data resolution concept)

128

General MIDI (GM) program

changes use a standardized system of 128 patch numbers (0–127 or 1–128) to ensure consistent instrument sounds across different synthesizers and devices.

MIDI Mode 1

Omni On/Poly

an instrument will respond to data that’s being recieved on any MIDI channel and then redirect this data to the instrument’s base channel

everything is polyphonic

MIDI Mode 2

Omni On/Mono

an instrument will respond to all data that’s being recieved at its input, without regard to channel designations

one note at a time

MIDI Mode 3

Omni Off/Poly

an instrument will only respond to data that matches its assigned base channel in a polyphonic fashion

most commonly used

MIDI Mode 4

Omni Off/Mono

an instrument will be able to respond to performance data that’s transmitted over a single, dedicated channel; each voice will only be able to generate one note at a time

often used in MIDI guitar systems

Quantization

the process of aligning musical notes or audio transients to a specific, rigid timing grid in a DAW, correcting timing errors by shifting them forward or backward to the nearest beat.

Purpose of synchronization in audio/video

to align sound with corresponding visuals to create a realistic, seamless viewing experience, specifically ensuring lip-sync in dialogue and matching audio cues to on-screen actions.

SMPTE Timecode

identifies an exact position within recorded media or onto tape by assigning a digital addres that increments over the course of a program’s duration

Longitudinal Timecode (LTC)

timecode that’s recorded onto an analog audio or video cue track of an older style video tape recorder

encodes a bi-phase timecode signal onto an analog track in the form of a modulated square waves at a bit rate of 2,400 bits/sec

MIDI Timecode

allows SMPTE based timecode to be distributed throughout the MIDI chain

Why sync is critical in production workflows

ensures audio-visual alignment, operational efficiency, and data consistency, preventing costly delays, errors, and wasted assets. In media, it ensures high-quality, aligned audio/video, while in business, it aligns teams and systems for accurate, real-time collaboration, saving time and resources.

Channel Output (CHOP)

sends signal into DAW, feeding Pro Tools

Split Mode

splits the channel into 2 paths

1. Channel Path, input/preamp feeding CHOP into Pro Tools

2. Monitor Path, out of Pro Tools to Faders/Ears

Safe Monitoring Concepts

listening to what’s being recorded, out of Pro Tools

Nominal gain structure

turn preamp up until it clips and then turn it down a little

Insert

directly into the signal path

EQ/Compressors

Sends

manage how signals move between tracks, buses, and outputs, allowing for parallel processing or sending multiple sources to one effect

Human User Interface (HUI)

enables motorized faders, knobs, and transport buttons on a hardware unit to interact with software, providing a tactile, analog-like experience for digital mixing and recording

Multipoint Control Unit

a server-side device or software that mixes multiple audio and video streams into a single feed for conferencing, minimizing client bandwidth.

Order of Channel Strip

1. Channel Input

2. Dynamics

3. EQ and Filters

4. Cue/FX

5. Channel Output

Number of EQ bands on SSL Duality

4

Order of bands

1. HF

2. HMF

3. LMF

4. LF

High Pass Filter

a circuit or algorithm that passes signals with a frequency higher than a designated cutoff frequency while attenuating (reducing the amplitude of) signals with frequencies lower than that cutoff

Low Pass Filter

a circuit or signal processing algorithm that allows low-frequency signals below a specific cutoff frequency to pass through while attenuating (reducing) signals with frequencies higher than that threshold

When filters are “out” of circuit

(often called "bypassed" or "hard-wired") in audio equipment, it means the signal is routed around the active filter components (such as capacitors, inductors, or op-amps) rather than through them

DRV In

routes the input signal to a completely different preamp featuring VHD circuitry

Group Faders

8

The TFT screen fitted above each channel bay is normally used to display a number of channel related parameters for the __ channels in that bay

6

Outputs

Top

Inputs

Bottom

Full Normal

breaks the default connection

Best for scenarios where you need to completely isolate a signal from its normal destination when patching it elsewhere, such as microphone inputs that should be disconnected from their original channel when routed to a different input or outboard preamp

Half Normal

inserted into top jack, not broken

inserted into bottom jack, broken

Generally preferred due to its flexibility. It's useful for occasional signal splitting and introduces minimal risk.

Why patchbays improve workflow

centralizing all audio I/O, allowing instant rerouting of signals from the front panel without accessing the back of equipment

Purpose of nearfield monitors

designed for close-proximity listening (roughly 2–5 feet away) to provide accurate, detailed sound by reducing the impact of room acoustics

Test tones used for balancing

Pink Noise

Audio vs AC separation

to prevent electromagnetic interference (EMI), commonly heard as a 50/60 Hz hum, buzz, or noise in audio signals.

Power Conditioning

keeping the purity and isolation of a room’s power from the outside world

Hums

noise that occurs as a result of imporoper grounding or sheilding

Aliasing

a form of digital distortion that occurs when a signal is sampled at too low a rate, causing high frequencies to be miscoded as incorrect, lower frequencies (aliases)

How to avoid aliasing?

utilize higher sample rates (e.g., 96 kHz) to raise the Nyquist limit, and enable oversampling (2x–8x) within plugins, especially for saturators, compressors, and distortion effects.

Artist vs Entertainer

live musicians are the entertainers

studio musicians are the creators/artists

What it means to “Serve the muse”

dedicating oneself entirely to the creative process, prioritizing artistic inspiration, and allowing that inspiration—rather than commercial success, ego, or strict planning—to guide the creation of work

Hard Microphone for a

Soft Instrument

Soft Microphon for a

Hard Instrument

What is Mic Hardness

a subjective, often perceptual quality—not a standard technical spec—where a microphone produces an aggressive, forward, or bright sound, emphasizing upper-midrange frequencies (5-10 kHz) and sharp transients