Intro To Audio

Multi track Recorder

Studio Loud Speakers

3 dB

A time delay between 2 or more waveforms

Degrees

It cancels out the sound

The way we differinciate between voicings, or tones.

• Partials: Frequencies that exist in addition to the fundimental frequency. (AKA "overtones")
• Harmonics: overtones that are whole number multiples of the fundimental freq.
• Ex: So let's consider the note that's 440 Hz (which is the A above middle C, referred to as A4). The harmonic partials of this note are:

• 440x1 = 440Hz (A4 -- the base note itself),
• 440x2 = 880Hz (A5, an octave above),
• 440x3 = 1320Hz (approx. the E6, the E above A5),
• 440x4 = 1760Hz (A6, two octaves above A4),

• simple: square, triangle and sawtooth waves. They're simple bc the have consistant harmonic structures, and they are continuous and repetitive.
• complex: dont necessarily repeat (ex: basic speach, instruments)

Also called "tonal balance", it is what makes a particular musical sound different from another, even when they have the same pitch and loudness. For instance, it is the difference between a guitar and a piano playing the same note at the same loudness.

the characteristic variations in level that occur in time over the duration of a played note. They're broken up into four parts: Attack, Decay, Sustain, & Release.

The time taken for a note to build up to its full volume, when the note is sounded.

How quickly th sound levels off to a sustain level after the initial attack.

The duration of the ongoing sound that is generated, following the initial attack decay.

How quickly the sound will decay once the note is released.

• How often and event occurs.
• Measured in Hertz (Hz)
• *Frequency has to do with pitch. The faster the frequency (or cycles per second), the higher the pitch.

Human hearing generally falls between 20 to 20k Hz (or cycles per sec.)

• P.H.E.W. F.A.V.
• Phase
• Harmonic Content
• Envelope
• Wavelength
• Frequency
• Amplitude
• Velocity

sine, square, triangle and sawtooth

• the loudness/volume of sound
• it is measured in decibels (dB)

0-120 dB

any device that converts one form of energy to another. Ex: a windmill, ears, microphone, speakers

• a measure of the amount of opposition in an AC current.
• represented by the letter Z (also shown as High-Z or Low-Z)

• 1. mic level
• 2. instrument level
• 3. line level

• a chart that shows the pitch response of a microphone or any sound capturing device
• the x-axis shows the response in Hz, the y-axis show it in dB

• the sensitivity of a mic's response at different angles.
• the path is 3D and has 3 catagories: omnidirectional, bidirectional, and cardoid

a change in frequency response of a directional mic as the sound source gets closer to the mic. The result is an increase in bass.

Reduction of a sound in amplitude. Measured in negative decibels. Example: -3db is a 3 decibel reduction.

Bright, Dark, Metallic, Warm, Tinny, Deep etc.

a stationary point in a mode of vibration

point of widest motion in a mode.

The Spectrum of a sound is the combination of frequencies that make up a complex timbre. Most often these are harmonics in various combinations and at various volumes.

A non-harmonic spectrum

Non harmonic and noise components of an otherwise harmonic spectrum. Breath, consonants, and air noise are examples.

the capacity of an object to emphasize certain frequencies while reducing others. A bottle has a resonant frequency.

a resonance in an instrument or voice that does not change with pitch.

When two copies of the same sound arrive at different times, either in a recording or in an actual space. If these two sounds are at similar levels and are within about 20 milliseconds of one another, a tonal coloration. The name is given because some frequencies will cancel and other frequencies between them will reinforce, forming a comb-shaped frequency response.

The spacing of the "teeth" is based on the delay between the two sounds, and the depth of the dips is based on the similarity of the two signals' volumes. When the two waves are equal in level, the comb filtering is most intense.

• 1. Two microphones at different distances picking up the same sound.
• 2. A strong reflection off a hard boundary like a wall or floor.
• 3. Multiple sound sources such as guitar cabinets all with the same source.

• 1. Observe a 3-to-1 microphone placement: One mic should be three times as far away from the source as another. This keeps the levels different enough to reduce comb effects.

2. Keep microphones away from strong boundaries, and avoid a mic between a nearby boundary and the source.

3. Avoid large numbers of speaker cabinets when recording guitar, and when possible mic one cone of the cabinet closely rather than putting the mic between cones.

4. Learn to recognize comb filtering and move your mics around until the signal is free of this sound.

• A term meaning a change in the waveshape of a sound, causing a change in timbre. Most distortion is undesirable and detracts from the quality of the sound.
• *There are cases, however, where distortion imparts character and could be considered beneficial.

A type of distortion that occurs when a circuit cannot reproduce the highest amplitude signals due to a lack of headroom. Typically the tops of waveforms are flattened creating the characteristic “clipped” waveshape.

In extreme cases the waveshape will look like a square or rectangle. The effect on the sound is to add harmonics that previously did not exist in the spectrum, causing a bright and buzzing sound. The nature of these harmonics is determined by the transfer function and symmetry of the clipping. Once a signal is clipped, it is very difficult or impossible to restore the recording.

This occurs when a signal exceeds the numeric limits of a digital system. This type of clipping is typically very harsh due to the unforgiving mathematical nature of the problem. Digital clipping will cause loud buzzing and popping sounds that usually render a recording unusable. Usually this type of distortion is symmetrical, leading to odd-numbered harmonics.

Depending on their design, analog circuits can clip in a way that is not sudden, but gradual, leaving rounded rather than flat tops on the waveform. Likewise, the onset of clipping is gradual rather than sudden, so their is no sudden transition to clipping. This is known as soft clipping and is less intrusive than the hard clipping sounds produced by digital devices. This type of distortion in small doses can actually benefit certain sounds, adding character.

Soft clipping is typical of tube and FET circuits.

Symetrical Distortion

Intermodulation

Equidistance, coincident pairing, and the 3:1 rule

Ensuring the 2 (or more) mics are the same distance away from the source

Placing the mics so close that the sound emitting from the source should hit the mics' diaphrams at the same time.

Setting one mic 3x the distance from the other mic, in relation to the source.

Ex: If mic A. is 2ft from the source, mic B. will be 6ft. (2ft x 3 = 6ft)

Spaced Pairing, XY Configuration, Blumlein Pairing, ORTF, & Mid-Side

2 cardoid mics placed apart from each other to produce 2 different recordings of the same instrument.

2 cardoid mics placed with their heads together at 90 degree angles. The result is that one mic will pick up the front left & back right of the room, and the other will pick up the front right & back left of the room.

similar to XY technique, however using 2 bi-directional mics at 90 degree angles.

A french made technique; also called a binaural technique which means its meant to approximate the response of your ears. Using 2 cardoid mics that are placed at a 110 degree angle w/the heads 7 in apart.

Placing one cardoid mic pointing at the source and a bi-directional mic placed perpendicular to the cardoid mic. They're both recorded onto one track. The track recorded with the bi-directional mic is copied and phase is inverted on the one copy. The 2 bi-directional tracks are then panned hard-left and hard-right, while the cardoid mic track is panned center.