Audio Fundamentals

The first format that uses a shorthand representation of musical notes and durations stored in numeric form is 

• MP3
• MIDI
• DSP
• MPEG

The process of recording a sound, stored in the form of thousands of individual measurements, each at a discrete point in time, is called

• Sizing

• Synthesizing

• Quantizing

• Sampling

What is used to compresses a stream of audio for storage and the decompresses for playback. 

• SWF
• FLV
• Codec
• MPEG

What is the standard range of human hearing?

• 2 Hz -20 Hz

• 2 Hz -20 kHz

• 20 Hz -20 kHz

• 20 Hz - 2 kHz

What is an audio?

• Human ears convert these electrical impulses to vibrations

• Sound from some object and hear by human ears

• The sensation that we perceived when vibrations in the air detected by our ears

• Transmitted to human brain via vibration

What is the file size of a 5 minute audio clip recorded in stereo with a sample frequency of 44∙1 kHz and a sample depth of 24 bits?

• 1.3 Mbytes

• 38 Mbytes

• 0.6 Mbytes

• 76 Mbytes

Which of these audio file formats support lossy compression?

• FLAC

• MP3

• WAV

• OggPCM

• WMA

Before a sound can be digitized, it must undergo several form of energy conversions. Which of the following sequence is CORRECT?

• Acoustic -> Electric -> Magnetic -> Mechanic

• Acoustic -> Mechanic -> Magnetic -> Electric

• Acoustic -> Magnetic -> Mechanic -> Electric

• Acoustic -> Magnetic -> Electric -> Mechanic

What is frequency aliasing?

• Aliasing is a common problem in signal conversion systems whose sampling rate is too slow to read input signals of a much lower frequency.

• Aliasing occurs when sample a signal too fast and obtain an incorrect frequency and/or amplitude as a result.

• Aliasing is an undesired effect in which the sampling frequency is too low to accurately reproduce the original analog content, resulting in signal distortion.

• Aliasing is a common problem in signal conversion systems whose sampling rate is too fast to read output signals of a much lower frequency.

Quantization noise is the difference between the actual value of the analog signal, for the particular sampling time, and the nearest quantization interval value.

• If voltages are actually between 0 to 1 but we have only 7 bits in which to store values, then effectively we force all continuous values of voltage into only 256 different values.

• At most, it can be as much as quarter of the quantization interval.

• Quantization noise decreases if the number of bits used in the digitization process are reduced.

• Quantization noise increases if the number of bits used in the digitization process are reduced.