Audio (1. & 2. Sem | 2024) Flashcards
What’s the Human hearing boundaries: frequency range (in Hz) and dynamic range (in dB SPL)?
The limits of our hearing range in terms of frequency: (20 – 20 000 Hz) and dynamic range (0 – 137,5 dB SPL)
How many dB correspond to “double sound pressure level”?
+6 dB
How many dB correspond to “double sound power or intensity”?
+3 dB
How many dB roughly correspond to “double perceived loudness”?
in the middle frequency range, about 250-2500 Hz, +10 dB
How much more power in W is required to get +10 dB SPL?
10 times the power in W
Equal Loudness Contour curves (ISO 226:2003). What do they show?
That our perception of loudness is not “linear” and depends on both the frequency and the dynamic range
Reference level (in dB) for electrical audio signals, consumer standard?
-10 dBV
Reference level (in dB) for electrical audio signals, professional standard?
+4 dBu
Reference level (in dB) for digital audio signals?
0 dB FS
Digital audio: relation between quantizing precision in bits and dynamic range?
Each bit ads about 6 dB dynamic range
Characteristics of Omnidirectional Microphone
- Omnidirectional – pure pressure transducer.
- the same sensitivity from sound coming from all directions
- very flat response across the complete frequency spectrum
Characteristics of Wide Cardioid or sub-cardioid Microphones
- cross between Omnidirectional (Omni) and Unidirectional (Cardioid) patterns, with mild directivity.
- to record instrumental groups in an orchestra, but without focusing too much on a single instrument
Charactersistics of cardioid Microhones
- Unidirectional, with pronounced directivity.
- This polar pattern has maximum sensitivity on-axis (0°), -6 dB from the sides (90° and 270°) and minimum sensitivity from the rear (180°).
- Standard close-up support microphone
Charactersistics of super-cardioid & hyper-cardioid Microhones
- cross between cardioid and bidirectional
- directional sensitivity than the cardioid
- the rear-lobe response is out-of-phase.
Charactersistics of shotgun Microhones
- cross between cardioid and bidirectional
- extreme directivity.
- example: to interview somebody in the middle of a noisy crowd
Charactersistics of figure of eight Microhones
- Bidirectional pattern – pure pressure gradient transducer.
- 2 two symmetrical sensitivity lobes, with maximum sensitivity on-axis (0°) and from the rear (180°); minimum sensitivity from the sides (90° and 270°).
- the rear-lobe is out-of-phase
Which microphone type has the best frequency response?
Condensor (best), ribbon (good)
Which microphone type has the most accurate transients??
Condensor (best), ribbon (good)
Which microphone type has the lowest self noise (S/N ratio)?
Condensor Microphone
Which microphone type has the highest sensitivity?
Condensor (best), dynamic (good), ribbon (bad)
Which microphone type has the highest headroom?
Dynamic Microphone
Which microphone type is best for live usage?
Dynamic Microphone
Which microphone types required phantom power?
- Dynamic (NO phantom power or batteries)
- Condensor (49V phantom power)
- Ribbon (NO phantom power)
Live amplification of vocals in a rock concert: what microphone would be the best choice?
(Between a dynamic cardioid, a condenser omni, a ribbon figure-of-eight and a PZM)
cardioid Dynamic
Live amplification of a drum kit in a rock concert: what microphones would you choose as
overheads? (Think about the requirements for impulse accuracy and high-frequency range
transparency …)
Condenser, because of accuracy in transient response and linear response in high frequency range
Dynamic only for the bass drum, since they have higher headroom
In which context can the “proximity effect” occur? (Think about the microphone type, polar
characteristic and distance from the sound source)
The “Proximity Effect” is an undesired boost of the lower frequencies that occurs when a microphone with directional polar pattern is placed very close to the sound source
In which context can “comb filtering” occur? (Think about multiple microphone sources, or
reflective surfaces in proximity of the sound source and microphone)
The interference from the direct and delayed sound wave causes a type of phase interference called “comb filtering”
What are the two basic principles used in stereo recording setups? (ITD and IAD)
ITD based on differences in time delay between the L and R channel, that are caused by the incident of sound waves when reaching the two microphones with time delays at different angles.
The IAD based on differences in amplitude (peak, level) between the L and R channel, that are caused by the varying sensitivity of the cardioid polar pattern at different incident angles.
Equalizers: In which situation would you choose a shelving EQ, a peak EQ or a hi/low cut filter?
SHELVING EQ general tone correction, to adjust the balance of the low and high frequency range. If an instrument just sounds too dark and muddy, or too thin and harsh
Peak EQ is used for accurate tone shaping, to remove or emphasize specific formants, to change the character of a sound, etc.
Low-Cut to eliminate low frequency noise or vibrations. For mechanical noise transmitted through the floor to the microphone stand, or traffic noise.
High-Cut Filter on bass range instruments to remove high frequency noise (hiss); it can be used to soften an otherwise aggressive instrument or special effect in dance and electronica styles
Dynamic effects: what is the purpose of a Compressor, a De-Esser, a Limiter and an Expander/Gate?
Compressor: reduces the level of the signal by a set ratio, once the signal level crosses beyond a defined threshold.
Limiter: works with a hard-knee curve, infinite compression ratio and very fast attack and release times.
De-Esser: reacts only to the frequencies in the specific range of “S”, “T” and other consonants (usually, a range between 5 to 10 kHz).
Expander/Gate: remove undesired, low dynamic level parts of a signal or to reduce/remove noise between vocal parts.
What effects can be used to add movement and dynamic changes in color (modulation) to an
instrument track?
chorus, flanger, phaser
What effects can be used to add space and depth to an instrument or vocal track?
delay, reverb
Which effect categories are generally used as send/return?
delay, reverbs
Which effect categories are generally used as insert?
EQ, filters, dynamics, distortion
Which effect categories can be used both as insert or send/return?
modulation effects and Distortion
Which notation type defines the exact pitch of the notes, but not their exact duration?
Square notation on 4-lines
Which are the most used metrical feet in musical context?
iamb, trochee, dactyl, anapest
How many lines does a standard modern notation staff (or stave) have?
5
What is the difference between beat, time signature and tempo?
Beat: The grouping of the underlying pulse of a Rhythm, Basic unit of time
Time Signature: how many beats in there are in each bar/measure
Rhythms: arranged with respect to a time signature, partially signifying a meter
Meter: organization of music into regularly recurring measures or bars of stressed and unstressed beats.
Tempo: how quickly the beat flows in bpm
In which tempo signature are these musical styles written in: Jig, Tarantella; Polka, March; Waltz,
Minuet; Pop/Rock, Techno, Trance?
4/4 = rock, blues, country, funk, and pop; allemande, bourrée.
2/2 = marches and fast orchestral music; gavotte
2/4 = polkas or marches
3/4 =waltzes, minuets, scherzi; sarabande; country & western ballads, sometimes used in pop
6/8 = double jigs, polkas, fast obscure waltzes, tarantella, marches, barcarolles, loures, and some rock music.
12/8 = baroque gigue (jig); common in slower blues and doo-wop, rock music.
In standard pop/rock/dance music written in 4/4, where is the snare drum usually placed?
2nd and 4th beat
The bass drum is typically used as a …
down beat instrument, 1st and 3rd
The snare drum is typically used as an …
up-beat or off-beat instrument, 2nd and 4th
What is a “drumbeat” or “drum pattern”?
A rhythmic pattern establishing the meter and groove through the pulse and subdivision, often defining specific music genre. Played on drum kits and other percussion instruments.
Which genres are “off-beat”?
Jass and Blues
What is groove?
sense of swing, soul or other genre, playing laid back or shaker tambourine is slightly before, tension makes groove