Audio Processing Techniques MIDTERM

Match the following relating to audio metering. 1. The '0' on an analog VU meter is calibrated to an electrical signal level of: 2. In standardized digital system, the LARGEST signal possible is: 3. In a standardized digital system, _____ is equivalent to '0 VU' in analog system. 4. According to the articles for Reading/Response #1, prior to PT12 typical DAW metering used was

1.+ 4 dBu 2. 0 dBFS 3. - 18 dbFS (EBU) or -20 dBFS (SMPTE) 4. sample peak meters

What delay times are typical for 'flanging'?

0-20ms

(EQ-IQ:Intro) According to Alex Case, there are many ways to affect 'spectral content' in a recording WITHOUT using 'EQ'. Two of the variables are [1] and [2].

1 - Mic Selection/Placement 2 - Tuning

In the diagram shown, identify each 'numbered' component

1 - direct sound 2 - early reflections 3 - reverb 4 - time

A 'spectrogram' allows simultaneous visualization of 1 (vertical axis), 2 (horizontal axis), and 3 (color intensity).

1 - frequency 2 - time 3 - amplitude

(Distortion) Match the term to its definition. 1. soft clipping 2. intermodulation distortion 3. hard clipping 4. asymmetric clipping

1. 'gentle' change at maximum output 2. energy at frequencies related to sum & difference components 3. 'abrupt' change at maximum output 4. 'even-order' harmonics

According to the 'delay chart' that we discussed in class, match the approximate amount of delay with the typical application. 1. discrete or 'ping pong' echo 2. doubling, phasing, flanging 3. 'slap' or 'bounce' echo

1. 150 - 400 ms 2. 1 - 35 ms 3. 50 - 150 ms

Match the following questions to their best answers. These come from class, readings, and videos. 1. Lifecycle of Sound in a Space 2. Effects Loop

1. A combination of direct sound, early reflections and reverberation that makes up the acoustic sound of a space. 2. Using aux sends and return tracks, this method allows you to use a single reverb for multiple tracks in your DAW

DYNAMIC EQ. Briefly describe how a 'dynamic EQ' differs from a traditional EQ (like those we have been discussing in class).

A dynamic EQ will only affect the selected frequencies when the signal goes past a certain threshold. A traditional EQ will affect the selected frequency no matter how loud or quiet that signal is.

Match the controls & their function on this Filter EFX plug-in. (Fuzz-Wah)

Modulation - controls the rate of the 'wah' frequency sweep up & down Filter - selects type of filter (HP/BP/LP) Pedal Min/Max Frequency - sets the limits of the 'wah' filter's frequency sweep Mix - balances of the amount of processed signal

Match the definition to the correct terminology about dynamics.

The music's rhythmic expression - microdynamics Loudness differences between sections of a 'track' - macrodynamics Use manual gain-riding/clip gain to manipulate this - macrodynamics Use dynamics processors to manipulate this. - microdynamics

Which diagram best depicts the result of 'flanging'?

a - orange lines

Select ALL of the typical operations or features of a 'deesser'.

adjust frequency to 'middle' of range to be reduced it is a fast compressor that attenuates annoying high frequencies (found in vocals, typically ~ 5kHz - 8kHz). adjust range to select amount of gain reduction

Which of the following are potential benefits of using 'clip gain' appropriately in the signal flow of a DAW?

allow the greatest resolution for adjustments near the '0' position on faders reduce the likelihood of inducing distortion in later processing in the signal path always keep the meters from 'peaking' regardless of their location in signal flow allow for easier panning in creating stereo mixes

A 'dynamic' EQ differs from a 'standard' EQ in that it...

alters amount of boost/cut based on amplitude of signal (rather than fixed change)

Match the dynamics terminology and its appropriate definition.

attack time - 'delay' prior to onset of dynamic adjustment threshold - point in signal level at which dynamic adjustment begins ratio - rate of 'change' after reaching threshold release time - 'delay' following dynamic adjustment to return to normal level

In EQ-IQ, Alex Case suggested that there are many methods that may be used to effect spectral content in recording or mixing WITHOUT using 'EQ'. Select from this list those that would LEAST likely do this.

changing from smaller to larger control room monitors using a different DAW changing bit depth of recorded files

Which effect is very simply represented here? (input,DELAY,LFO,gain,output)

chorus

(Basics & Design) 'Analog' spectral processors operate as [1] functioning devices in the frequency domain, while 'digital spectral processors operate on [2] data in the time domain.

continuous , discrete

According to Sabine's Equation, the Reverb Time or RT60 of an acoustic space is based mostly on [1] and [2],and varies with frequency.

cubic volumes absorption of materials

Match the diagram to the name of dynamic function.

multi-band compressor, de-esser, key input broadband compressor, broadband compressor

(Basics & Design) The 'phase response' of a spectral processor will affect the sonic character of the signal passed through it. Analog spectral processors are always [1] phase type, while digital spectral processors may be [2] phase unless they are modeled to be like analog processors.

non-linear, linear

(Spectral Repair / EQ-IQ: Fix) Audio 'noise' may include pink noise which is equal energy per [1] and white noise which is equal energy per [2].

octave , frequency

Match the spectral processor device characteristics (on the left) to the device classification (on the right).

operate on discrete data - digital frequency domain - analog continuous functioning - analog time domain - digital

We discussed three basic (general) categories of USES for which spectral processing can be applied in music recording/mixing, which are reinforced in the EQ-IQ video. These are (IN SEQUENCE):

overcome deficiencies - fix affect a better blend - fit alter for creative reasons - feature

Match the 'family' of reverb with the typical example.

rooms - acoustical processors - digital plate - mechanical spring - mechanical chambers - acoustical plug-ins - digital

The function or purpose of audio metering is to (select ALL that apply):

show specific audio characteristics display the measured level in an objective manner

Match the 'type' of compressor with its most basic characteristic.

tube - level detector drives the gain of the tube digital - algorithms influence gain optical - light source & light sensitive resistor influence gain FET - solid-state electronic device (e.g. VCA) changes the gain

Select ALL benefits of using a 'send/return' procedure for adding 'reverb'.

easier to combine 'dry' sound with 'wet' sound allows sonic blending of multiple instruments in reverb easier to maintain similar reverb sound across multiple instruments reduced CPU power required over applying in 'insert' style

Complex sounds are made up of many discrete parts. Match the related terminology to its definition.

fundamental - lowest frequency present in a musical tone overtones - all other frequencies present harmonics - whole number multiples only timbre - relative intensities that are key to an instruments sound

(Introduction) 'Spectral processors' affect the balance between the ____ and ____ , which together make up the 'timbre' of the instrument.

fundamental ; overtones (harmonics)

Detail an idea or concept about 'level & metering' or 'spectral processing' that you have discovered this semester from class discussions, readings, videos, labs, or your own work, AND explain how it has or will influence your recording/mixing of music.

getting an overall understanding of what each metering is showing you is a great option to recieve an objective opinion on your audio signals. I very often use PPM meters to make sure whatever I am recording is not clipping. I also use RMS and LUFS all the time once I am done with my mix to measure the perceived loudness of my finished mix

FILTER EFX. The 'wah wah' pedal creates a distinctive effect, which it supposed to mimic the [1], and was originally intended to imitate the sound produced by a [2] trumpet

human voice, muted

The 'wah-wah' pedal creates a distinctive effect, which is supposed to mimic a _. It was originally intended to imitate the sound produced by a ____.

human voice; muted trumpet

Typical applications for using dynamic processing include: (select ALL that apply)

- overcome 'noise' (allow overall volume increase) - overload - increase perceived loudness - improve intelligibility (smooth performance)

With a Threshold set to -20db and a ratio of 2:1, and the input signal is at -5db, what is the output level?

-12.5db

Match the following characteristics to the type of metering. 1. displays a 'peak' then holds for period of time 2. give better impression of perceived loudness 3. good for evaluating peaks to avoid overload 4. similar in response to the human ear 5. emulate VU meters in a digital system 6. good for continuous duration sounds (i.e. music) 7.poor for monitoring continuous duration sounds (i.e. music) 8. does NOT register 'peaks' or 'transients'

1. PPM 2. RMS 3. PPM 4. VU 5. RMS 6. VU 7. PPM 8. VU

OTHER SPECTRAL PROCESSING PLUG-INS. Match the spectral processing plug-in name to their function.

1. Talkbox - adds a voice-like resonance 2. Kill EQ - filters out low, mid, high broadband frequency range 3. Vintage Filter - applies a modulating, resonant filter 4. Enhancer - generates harmonics

Match the following questions to their best answers. These come from class, readings, and videos. 1. Wet/Dry Mix 2. Direct Sound 3. Pre-Delay 4. Early Reflections

1. The blending parameter the engineer can use to balance the amount of direct signal versus the reverberant signal 2. The original impulse of sound that is created 3. The gap in time between the direct sound and the onset of the reverb tail 4. The first echoes that 'bounce back' in a space, indicating the size of the space

Referring to this diagram, explain what will be perceived by the listener as the delay time (T) is varied. 1. > 35 ms 2. ~ 0.5 ms to ~ 30 ms 3. 0 ms

1. The sound will appear to first come out of the left speaker with a delayed repetition coming from the right speaker 2. The sound will appear to come from the left speaker first with a fused sound widening out to the right 3. The sound will appear to come from the center of the two speakers ('phantom center') in front

(Spectral Repair) Match the recorded 'noise problem' with the best plug-in solution: 1. 50/60 Hz + harmonics line frequency noise 2. pops & tics on 'records' 3. analog tape hiss or similar

1. debuzzer 2. declicker 3. denoiser

(Distortion) Match the term to its definition. 1. anything that is NOT part of the intended signal 2. particular artifact that is correlated with the signal 3. high level on the signal peaks 4. hiss, rumble (HVAC), wind, etc.

1. noise 2. distortion 3. distortion 4. noise

Match the type of processor with its primary function or characteristic. (temporal, dynamics, spectrum) 1. change 'timbre' of the sound 2. change the acoustic envelope 3. 'change' the acoustic environment 4. affect the time relationship of signals 5. affects the frequency/amplitude response pattern 6. affect the dynamic range

1. spectrum 2. dynamics 3. temporal 4. temporal 5. spectrum 6. dynamics

FILTER EFX. Match the controls & their function on this Filter EFX plug-in. 1. Pedal 2. Filter 3. Frequency 4. Mix

1. sweeps the 'wah' center frequency up & down 2. selects type of Filter (HP/BP/LP) 3. sets the limits of the wah filter's frequency sweep 4. balances of the amount of processed signal

(Spectral Repair/EQ-IQ: Fix) Match the following related to audio spectral 'noise' types. 1. Impulsive 2. Continuous/Broadband 3. Continuous/Tonal

1. tics, pop, clicks, crackles 2. white noise, pink noise, rumble, hiss 3. feedback, hum, buzz

What are typical delay time settings for the above effect? (Chorus)

15-35ms

Match the digital system 'bit depth' to its possible 'dynamic range'.

24bit - 144dB 16bit - 96dB

(EQ-IQ:Process) Not all frequencies are present in all genres of music. The range of the acoustic piano represents the 'fundamentals' of most instruments, which include the frequencies from approx. ___ Hz to ____ Hz.

30 ; 4000

Not all frequencies are present in all genres of music. The range of the acoustic piano represents the 'fundamentals' of most instruments, which include the frequencies from approx. ___ Hz to ___ Hz.

30 Hz - 4000 Hz

Approximately how long does it take for sound to travel the LONGEST dimension of this space?

40 ms

For appropriate 'musical' slap echo, the formula for the calculation for delay time is....

60,000 divided by the BPM of the song.

Identify the following (A, B, C, D) according to our class discussions. (Study Picture)

A - Dynamic Range B - Signal to Noise C - Headroom D - Reference Level

Match the letter to the measurment on a typical sine wave signal. (Study Picture)

A - Period B - Peak Amplitude C - Peak To Peak Amplitude D - RMS Amplitude

(Spectral Analysis) Identify what parameter each of the 'letters' indicate in the display below... (Study Picture)

A - amplitude/intensity B - time C - frequency D - time E - amplitude/intensity

The TWO adjustable controls on a typical FILTER (hardware or plug-in) are shown on the figure below. These are the (A)_ and (B)_.

A - corner/turnover frequency B - slope

In the final EQ-IQ videos, Alex Case suggests that the 'total sound' of any instrument (e.g. guitar) is made up various frequency ranges that encompass the:

A - fundamentals B - harmonics & harmonic distortion C - performance gestures D - reverb

EQ-IQ: REVERB & SPECTRAL. In the final EQ-IQ videos, Alex Case suggests that the 'total sound' of any instrument (e.g. guitar) is made up of (Study Picture)

A - fundamentals B - harmonics & harmonic distortion C - performance gestures D - reverb

The TWO adjustable controls on a typical FILTER (hardware or plug-in) are shown on the figure below. These are the A and B.

A -corner/turnover frequency B - slope

Match the reverb type to its typical characteristic or definition.

Acoustic chamber - Gently decaying energy across the frequency spectrum Spring reverb - Lots of energy around 250 Hz Plate reverb - Lots of energy between 1kHz - 8kHz Algorithmic reverb - Calculation based on hypothetical rooms or types Convolution reverb - Utilizes the impulse response of a room derived from a single sound to generate a pattern of reverb Non-linear reverb - Rearranges the 'reverb' normal cycle of direct, early and late reflections

What are the implications for use of EQ in music mixing presented in this chart (titled 'Masking as a Function of Amplitude') and class discussion (EQ-IQ:Fit)?

As level of 'distraction' increases, so does the range of frequencies increase (upward spread effect), resulting in loud low frequency events (bass/kick) 'masking' mid-frequency events (vocal).

The function or purpose of audio metering is to (select ALL that apply)

BOTH (a) and (b) a. display the measured level in an objective manner b. show specific audio characteristics

This graph shows the composite frequency response curve of one type of equalizer. The left-most response curve represents a C equalizer , and the right-most curve represents a D equalizer. The TWO typical adjustment parameters of this type of EQ are A and B

C - low frequency shelf D - high frequency shelf A - corner/turnover frequency B - gain (boost/cut)

FILTER EFX. The inner workings of the 'wah wah pedal' are fairly simple. The foot pedal controls the [1] of a bell curve EQ or pass filter with a gain boost

Center Frequency

Match the following related to audio spectral 'noise' types.

Continuous/Tonal - feedback, hum, buzz Impulsive - tics, pop, clicks, crackles Continuous/Broadband - white noise, pink noise, rumble, hiss

This graph represents the response curve of the most common type of equalizer, called a D equalizer. 'A' (vertical axis) is the _. 'B' (horizontal axis) is the _. 'C' (width) is the _.

D - peak/bell curve A - gain (boost/cut) B - center frequency C - bandwidth

Match the following questions to their best answers according to readings, videos, and class discussion

Delay time - Typically set in milliseconds, controls the amount of time the signal is held before output Low Pass Filter - Attenuates high frequencies, creating the illusion of distance Feedback - The amount of delayed signal sent back into the delay input for additional repeats Polarity Reversing - Allows us to shift the spectral impact of the effect to different frequencies LFO - Low frequency wave that modulates the audio Depth - Adjusts the spread between minimum and maximum delay times

Match the following terminology and parameters to their definition based on readings, videos, and class discussions.

Direct Sound - The original impulse of sound in an environment Early Reflections - The first echoes that bounce back in a space, indicating the size of the space Reverb Tail - The series of diminishing late reflections in a space. Reverb Time/RT 60 - The amount of time it takes for the reverb to decay by 60dB Pre-Delay - The gap in time between the direct sound and the onset of the reverb tail. Wet/Dry Mix - The blending parameter the engineer can use to balance the amount of direct signal versus the reverberant signal Diffusion & Density - Drive the build up of complexity within the reverb sound Bass Ratio/Bass Multiply - Determines how much longer the low frequencies linger in the reverb algorithm.

(Basics) There are three basic 'uses' for which spectral processing can be applied in music recording/mixing. These are (in order as we discussed them in class) [1], [2], and [3].

Fix, Fit, Feature

ONE 'sonic issue' that may be improved by using 'FILTERS' (according to Alex Case in EQ-IQ FIX) is [1] .

Hum, Buzz, Proximity effect etc...

The 'law' that relates the above phenomenon (with time delay on one side) is called the _, which also refers to the _ effect and the_ effect

Law of the First Wavefront, Precedence, Haas

The 'law' that relates the above phenomenon (with time delay on one side) is called the _, which also refers to the _ effect and the_ effect.

Law of the First Wavefront, Precedence, Haas

In the EQ-IQ: Parameters, several analog EQ's are reviewed. Match each 'device' to the ONE correct 'characteristic' mentioned

Manley Massive Passive - small 'bump' just ahead of the corner frequency API 550b - proportional Q (BW) Pultec EQP-1 - combined effect of controls (i.e. may boost & cut simultaneously) API 215L - different 'slopes' for high-pass and low-pass

What are the implications for use of EQ in music mixing presented in this chart (titled 'Masking as a Function of Frequency') and class discussion (EQ-IQ:Fit)?

Our hearing threshold changes in the presence of 'distracting tones', and these 'distracting tones' will mask nearby frequencies.

Match the following questions regarding temporal processing to their best answers. These come from class, readings, and videos

Pre-Delay - The gap in time between the direct sound and the onset of the reverb tail Direct Sound - The original impulse of sound that is created Reverb - Late Reflections (related to size and characteristics of the space) Early Reflections - The first echoes that 'bounce back' in a space, indicating the size of the space

Q-IQ: REVERB. According to Case's video, how does 'reverb' add spectral content to an audio signal?

Reverb emphasizes the frequencies which adds spectral content to the signal by having longer resonance. Reverb also contributes to the timbre of the Instrument

Match the following terminology to its definition according to readings, videos, and class discussions.

Reverberation - A combination of direct sound, early reflections and 'ambience' (late reflections) that makes up the acoustic sound of a space. Chamber Reverb - A staple sound in early recordings from the 50's to the 80's. Generated by projecting sound into a large reflective space and capturing it with a microphone for mixing back into the recording. Plate Reverb - A system for generating artificial reverb involving a large sheet of metal suspended in a box Effects Loop - Applying aux sends and returns structure allowing use of a single reverb for multiple tracks

OTHER SPECTRAL PROCESSING PLUG-INS. Match the spectral processing plug-in name to their function.

Talkbox - adds a voice-like resonance Kill EQ - filters out low, mid, high broadband frequency range Vintage Filter -applies a modulating, resonant filter Enhancer - generates harmonics

Which diagram BEST depicts how 'flanging' was originally accomplished?

Tape Picture

Match the following techniques and applications in using reverb.

Using 'room mics' - Adds natural ambience that is linked to the direct sound Adding early reflections - Will add back in realism to tracks that have been close-miced and robbed of their realism EQ - Can be used to reshape the timbre of a reverb, such as extending highs or removing lows To create contrast and separate various instruments in the mix - Use different types of reverbs on various instrument groups to minimize competition between tracks. Stretching the Pre-delay longer in time - makes it easier to hear the reverb itself and prevents the dry signal from obscuring the reverb sound.

Delay, as discussed in this class, is a specific form of audio signal processing. [1] delay uses a physical means to 'hold back' a signal. One example of this is [2].

analog, tape delay

(EQ-IQ:Process) According to Alex Case, the conventional procedure for using an equalizer has the following three steps (in sequence):___, ___, and ___ .

boost / search / set

According to EQ-IQ, the PROCEDURE for using an equalizer has the following three steps (IN ORDER):

boost, search, set

Delay, as discussed in this class, is a specific form of audio signal processing. [1] delay uses a 'buffer' to hold a signal for a set amount of time. One example of this is [2].

digital, delay plugins

According to the 'delay chart' that we discussed in class, match the approximate amount of delay with the typical application.

discrete or 'ping pong' echo - 150 - 400 ms doubling, phasing, flanging - 1 - 35 ms 'slap' or 'bounce' echo - 50 - 150 ms

This diagram shows the basic effect process known generally as [1], and also referred to as 'ADT' or [2].

doubling, automatic double tracking

EQ-IQ: FEATURE. Musical sounds that are '1' create '2' energy. Examples include instruments such as '3' and '4'.

impulsive, broadband, kick, snare

The 'phase response' of a spectral processor will affect the sonic character of the signal passed through it. ANALOG spectral processors are ALWAYS _____ phase type. DIGITAL spectral processors may either emulate such analog devices OR they may also be designed to be ______ phase.

minimum; linear

a unique spectral processing device, called 1 EQ, was proposed in an AES paper in 1972 by inventor 2 . It allowed for 3 control of 4 , gain, and bandwidth.

parametric George Massenburg continuous center frequency

In EQ- IQ, Alex Case refers to the 'VOLUME CONTROL' as a(n):

perceptual EQ

(EQ-IQ:Process) Alex Case refers to the volume control as a(n) '_____', because spectral changes appear to us to be affected by _____.

perceptual EQ ; volume/level

What effect is shown very basically here? Allpass-allpass-allpass-depth-feedback

phasing

Match the following effects to their typical response/result.

phasing - 'peaks and troughs' are NOT related harmonically flanging - 'peaks and troughs' ARE related harmonically

(Estimating the Frequency of Sound) According to this exercise, ____ (type of signal) is/are more useful in equipment testing and measurement, whereas ___ (type of signal) is/are more useful in acoustic testing and measurement.

pure tones ; pink noise

EQ-IQ: SPECTRAL. Alex Case reminds us to create 1, NOT 2 in order to properly adjust spectral content.

strategies, recipes

EQ-IQ: FEATURE. In the final EQ-IQ videos, Alex Case recommends that you develop '1' for each instrument that represent the 'spectral '2' of each instrument.

templates, landmarks

(EQ-IQ: Parameters) List TWO characteristics that were ascribed in the EQ-IQ 'Parameters' video to specific analog equalizers, e.g. API 550, Massive Passive, etc.

these analog pieces of gear often introduce noise, rumble, buzz or hiss into our recordings. The massive passive features a nice boost around the 1.5kHz range when using a low-pass filter set to certain settings (like 6.5kHz or 9kHz) and the Pul-Tech Eq1 gives you a really cool sound if you boost and attenuate the same frequency as it will boost the frequecy right below the selected frequency, and cut right above.

Pitch shifting' relies on [1] the amount of delay in specific controlled ways in order to raise or lower the original pitch by musical intervals. This 'effect' was first made possible using [2] , which changed both the pitch and the [3] simultaneously.

varying, analog, tempo

(How the Ear Analyzes Sound) The human auditory system acts as a(n) '_____' . Using it, we can "hear out' the harmonics of a complex sound until we reach the point where two of these are within the _____, which is about 15-20 % of the frequency being considered.

wave analyzer ; critical bandwidth