BPM202: Digital Music Production II - QUIZ #3

MICROPHONES

• There is no such thing as a bad microphone, but a microphone's range of uses may be limited

• Microphones convert sound energy into electrical energy using different types of diaphragms

• Used for a variety of instruments & voices

TYPES OF MICS

1. DYNAMIC

2. CONDENSOR

3. RIBBON

4. OMNIDIRECTIONAL (OMNI)

TYPES OF MICS

1. DYNAMIC

• Use a diaphragm attached to a coil of wire in a magnetic field

  • Work like speakers but in reverse

  • Sound wave deflects a diaphragm attached to a coil of wire sitting in a magnetic field

  • This movement causes the sound to be converted into a small voltage

  • Very durable, broad frequency response & dynamic range

TYPES OF MICS

2. CONDENSOR

• Diaphragms are capacitors

  • Received sound impinges upon and moves (very slightly) a diaphragm that is one of two plates that make up the capacitor

  • Movement changes the spacing between the two plates, causing a change in the capacitance value, which produces the sound as a change in the voltage passing through it

  • This voltage is so small that an internal amplifier is usually required in this type of microphone → need

TYPES OF MICS

3. RIBBON

• Utilize a thin strip of metallic foil within a magnetic field

• Very sensitive with a smooth frequency response and natural sound but can be damaged by high SPL and wind (so there’s usually furry blimp-like surrounds applied to them when used outdoors)

• They add little to no noise to the signal and have excellent low-frequency pickup capabilities

TYPES OF MICS

4. OMNIDIRECTIONAL (OMNI)

• Non-directional mics are designed to pick up sound from all directions fairly equally

• More “open” sounding & have no proximity effect

3 COMPONENTS TO SOUND

1. Volume (Amplitude)

2. Frequency

3. Time

CATEGORIES OF SOUND EQUIPMENT

1. Sound Creators: Instruments, acoustic to electric, voice to synths

2. Sound Routers: Mixing boards, patchbays, splitters

3. Sound Storers: Recorders, tape players, sequencers, samplers

4. Sound Transducers: Mics, pickups, headphones, speakers

5. Sound Manipulators: Processing, effects

What is the function of VOLUME FADERS?

• Volume faders control the volume of each sound in the mix, including effects, based on its relationship to the rest of the tracks

What is the apparent volume of a sound in a mix?

1. Fader level

2. Waveform

3. Fletcher/Munson Curve

How does waveform affect apparent volume?

• The waveform, or harmonic structure, of a sound can make a big difference as to how loud the sound is perceived to be

What does the Fletcher/Munson Curve explain?

• The human hearing process does not perceive all frequencies at the same volume, especially at low volumes

• Mixes should be checked at all volume levels

What are the main functions of a compressor/limiter?

• To get a better signal-to-noise ratio —> less tape hiss

• To stabilize the image of the sound between the speakers

  —> more presence

What do ratio settings on a compressor/limiter control?

• Ratio settings control how much (by percentage) the sound volume will be turned down when it goes above the threshold

What is the function of a noise gate?

• A noise gate cuts off the attack and release of a sound or can be put on reverb to chop off the release, resulting in "gated reverb"

What is EQ?

• EQ is a change in the volume of a particular frequency of a sound

List the three main types of equalizers found in recording studios

1. Graphics

2. Parametrics

3. Roll-offs (highpass and lowpass filters)

What is a paragraphic equalizer?

• An equalizer with frequency sweep knobs but no bandwidth knobs

What is the function of a highpass filter?

• A highpass filter rolls off the low frequencies but passes the high frequencies

What is the function of a lowpass filter?

• A lowpass filter rolls off the high frequencies

Six Frequency Ranges

• Low Bass: Less Than 40Hz

• High Bass: 40Hz - 80Hz

• Low Midrange: 160Hz - 320Hz

• High Midrange: 640Hz - 1280Hz

• Low Treble: 2560Hz - 5120Hz

• High Treble: 10,240Hz - 20,480Hz

What are harmonics or overtones?

• The other notes hidden in a sound when an instrument plays a particular pitch

What is the root frequency?

• The basic pitch perceived when hearing a sound

List three main things to check when EQ'ing

• If the sound is muddy

• If there are irritating or "honky" frequencies in the midrange

• If the sound is bright enough

What frequencies should be cut to reduce muddiness?

• Frequencies around 300Hz

How fast does sound travel?

• Approx. 1130 feet per second

What is "doubling" in relation to delay?

• Delay time in the range of 30 to 60ms, which makes a sound seem like it was played twice

What is "fattening" in relation to delay?

• Delay time between 1 to 30ms, which makes one fatter sound

What delay time causes phase cancelation?

• 0 to 1ms

What is reverb?

• Hundreds and hundreds of delays

What is diffusion in reverb?

• The density of the echoes that makes up the reverb

What is "preverb?"

• A reverb effect on something before it happens

What is a microphone?

• A transducer that converts acoustical energy into electrical energy

• Microphones have different types, including dynamic, condenser, electret, carbon, and ribbon

How does a dynamic microphone work?

• A sound wave deflects a diaphragm attached to a coil of wire sitting in a magnetic field

  • This movement converts the sound into a small voltage

  • Dynamic microphones are very durable with a broad frequency response and a dynamic range

How does a condenser microphone work?

• Received sound moves a diaphragm that is one of two plates that make up a capacitor

  • This changes the spacing between the two plates, changing the capacitance value, which produces sound as a change in the voltage passing through it

• Condenser microphones require powering

What are the advantages of condenser microphones?

• Produce a minimal amount of noise and can handle all but the most excessive input levels

• They handle high frequencies smoothly and have a superior transient response

How do ribbon microphones work?

• A thin strip of metallic foil is surrounded by a magnetic field. The metal strip acts as a single turn coil, making the diaphragm and the coil one and the same

• They are very sensitive with a smooth frequency response and a natural sound, adding little to no noise to the signal and have excellent low-frequency pickup capabilities

• They can be susceptible to damage from high SPL inputs and wind noise

What is proximity effect?

• The closer a microphone is placed to the sound source, the greater the input, especially at low frequencies

What is a polar pattern?

• A diagram that shows the variation per frequency of a microphone’s pickup characteristics as per the direction of the sound source

• Microphones can be omnidirectional, bidirectional, cardioid, hypercardioid, or shotgun

What is a pressure zone microphone (PZM)?

• A common capacitor microphone mounted very close to a flat boundary or plate

• The direct sound it picks up arrives at the same time as those reflected from the boundary

Phantom Power (48 Volts)

• Requires an outside source

• DC is needed to power electronics & charge diaphragms of condenser mics

• Has no effect on audio & causes no problem when connected to microphones that do not require power like dynamic mics

• But sometimes, with some older mic power supplies, there’s an occasional popping noise (due to capacitive discharge) → so… turn off phantom power on console channels before these mics are connected to them

  • Condensors today produce a minimal amount of noise, their specs always include noise & maximum sound pressure level (SPL) ratings

MULTI-TIMBRAL

• Allows you to play different timbres AT THE SAME TIME