Sampling

Question 1

What is sample rate?

Answer 1

Sample Rate is how often a sample is taken

x axis on a graph

Question 2

What is bit depth?

Answer 2

Bit Depth is how detailed the measurements are. Number of possible amplitude measurements. It also limits the SNR
(y axis on graph)

Question 3

What is the Nyquist Theory?

Answer 3

The Nyquist Theory states that sample rate must be twice the frequency in the audio file. Must be twice the highest frequency captured.
Hence the choice of 44,100, double the human hearing range.

Question 4

What happens when sample rate isn’t high enough?

Answer 4

Aliasing happens, where the sample rate is too low to represent the sound wave accurately.

Question 5

How can aliasing be avoided?

Answer 5

Use a higher sample rate or an anti-aliasing filter

Question 6

What is quantisation?

Answer 6

Where the bit depth is rounded up or down. The further something is quantized, the more distorted is sounds

Question 7

How can distortion be avoided?

Answer 7

Make sure the bit depth is high enough, so the quantisation doesn’t go too far.

Question 8

What is a sampler?

Answer 8

An electronic instrument that records and plays short snippets of sound

Question 9

How can samples be manipulated?

Answer 9

Pitch shift, speed shift, Reversed, Distortion, LFO,

Question 10

What is the EMU SP-1200?

Answer 10

Classic Drum machine and sampler

• 12-bit sampler with 26kHz sample rate
• Contains drum presets
• Lo-fi Sound

Question 11

What does Lo-Fi mean?

Answer 11

Low-Fidelity

Question 12

What is the Akai-S900?

Answer 12

First professional Akai sampler, 1986

• 12 bit stereo sampler with 7.5kHz to 40kHz sample rate
• Maximum 63 seconds of sample time at 7.5kHz
• 75kb of RAM
• Had an ADSR

Question 13

What was an early Digital Musical Interface that had a synth and sampler?

Answer 13

Fairlight CMI

Question 14

How has the ability to change pitch in samplers developed?

Answer 14

Originally, this was done by speeding up or slowing down samples
Nowadays, digital sound processing allows this process to be instantaneous.

Question 15

What is the Mellotron?

Answer 15

The mellotron is a tape-based, polyphonic analogue sampler, used throughout the 60s and 70s

Question 16

How does the Mellotron work?

Answer 16

• The mellotron works by pressing a tape head onto a length of tape when a key is pressed.
• It plays a note which lasts until the tape runs out

Question 17

What is velocity layering?

Answer 17

Enables us to record samples from live instruments at a range of velocities and control when to trigger them,

Question 18

What is multisampling?

Answer 18

Multisampling is where more than one sample is used, meaning each sample can cover a smaller range

Question 19

How is multisampling effective?

Answer 19

It is used to improve the realism of a sample because they don’t have to be pitch shifted as far. Limiting how far a sample has to be pitch shifted keeps consistent timbrel properties of a note.

Question 20

Why did drum machines embrace early sampling technology?

Answer 20

For one shot samples

Question 21

What is aliasing?

Answer 21

Aliasing happens when the sample rate is too low to accurately represent the frequencies of the sound.