Test your basic knowledge |

Digital Audio

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Eliminates frequencies above the Nyquist limit from becoming samples; Occurs prior to quantization






2. How Loud (Y-Axis) & How Fast (X-Axis)






3. High channel count; 64 channels on one cable; Coaxial cable with BNC connector or fiber optic with ST1 connector






4. Snippets of time in which frequency analysis takes place in a perceptual codec






5. Lossless Format; Can hold up to 25GB on a single- layer disc and 50GB on a dual- layer disc






6. 1.) Taking a series of evenly- spaced measurements 2.) Signal contains no frequency components higher than half the sample rate






7. Digital and analog processing capability is combined on a single microchip allowing for 1- bit resolution at high sample rates






8. Father of modern information theory; Solidified the Nyquist Theory by adding the concept that bits per second (binary representation of audio signals) must be at equal intervals to accurately represent data






9. Reference voltage determined by summing the voltage values of a predetermined number of previous samples; Numbers of 1 in row = waveform peak; Numbers of 0 in row = waveform trough; Basis of Sony's Direct Stream Digital (DSD)






10. Twice as many samples as the highest frequency at minimum; Sampling rate totally controls frequency response






11. Pertaining to hearing or sound; Combination of the intensity of air pressure molecules with amplitude






12. Multi-Bit Words; (Pulse Code Modulation)






13. Ultra low- latency - 512- channel (on a gigabit network) - less flexible AoE format; Routed like audio cables...not network cables






14. 15.9 GB; DS/DL






15. Digital Word -> Series of Resistors (each with assigned charges) -> Sample- and-Hold Circuit -> Anti-Imaging Filter (Smoothing Filter) -> Reconstructed Sample






16. Contains all even and odd harmonics associated with a fundamental tone - making it a rich source for modeling other sounds; Amplitude of each overtone decreases exponentially as a ratio of the harmonic's frequency to that of the fundamental






17. AES






18. Improper (false) sampling of high frequencies that cause much lower frequencies to be produced when the audio is reconstructed; Foldover happens at higher frequencies as harmonics reach levels that exceed the Nyquist limit.






19. A drive that can read and write on optical media that hold up to 50 GB on two layers; 24- bit/96 kHz for 8-Channel; 24- bit/192 kHz for 6-Channel






20. Sony sigma- delta modulation based technology that bypasses the decimation and interpolation steps found in PCM converters






21. Root Mean Square; Refers to taking the square root of all instantaneous amplitudes; Takes the average of those squares; (-6 Peak Level is approximately equal to -20 RMS)






22. Describes various optical disc characteristics including the size and shape of the disc - the size of pits - the speed at which the disc spins - and a multitude of aspects regarding the specifications of the player itself






23. Increases or decreases the digital signal so that the loudest sample is brought up to 0dBfs; Uses all bits from dynamic range and makes it even from track to track






24. Playback; I/O Connections; CPU (Streaming); Conversion from DAW or Software






25. Sony and Philips optical disc format; Utilizes sigma delta DSD to offer higher resolution; 1- bit; 2.8224 MHz; 6-Channel






26. The difference between the analog value and the approximated digital value due to the 'rounding' that occurs while converting the analog signal to digital






27. Full Scale; Type of metering that measures level in digital recording system; Recording and Mixing levels should NEVER exceed 0dB FS in digital audio or clipping will occur






28. Method of representing an acoustic quantity with a series of binary numbers; Can have only specific individually distinct values






29. Data is transmitted over fiber optic lines; Uses a TOSLINK connecter instead of an RCA type; Can transmit multi- channel audio; Not susceptible to ground hum and loops; Able to support far higher rates of data transfer over greater distances than coa






30. When recording you want the smallest buffer available; When mixing you want the largest buffer available






31. Difference in brightness between land and pit on a CD Physical Format






32. 'Capturing' part of digital audio; Never captures a signal perfectly






33. Psychoacoustic model of data reduction used for general audio compression that aims to transmit only features perceptible to the human ear; Useful for mastering streaming media






34. Roughly around 1 -130 ft/s






35. 8- in/8- out on one cable; 25- pin D- sub connector






36. Sum of all harmonics; Sum of sine and cosine waves which have frequencies f - 2f - 3f - 4f...






37. Reduces A/D sample rate from the oversampled rate to nominal rate by turning series of one- bit samples into a series of multi- bit PCM samples; (ex. => 2.8MHz sample rate converted to 44.1kHz and simultaneously converts 1-Bit samples to multi- bit);






38. Series of dots and dashes representing the letters of the alphabet; Most common letters are represented by the shortest dots and dashes; Example of entropy coding






39. The loudest point of a Full Scale system






40. Cable used to transmit data; Inner cable is surrounded by a plastic insulator - which is surrounded by a wire mesh conductor that insulates the internal signal wire from external interference and an outer casing that functions as a ground






41. Governs the frequency response of a digital system; The highest- frequency component that can be captured with a sampling rate; always 1/2 of sampling rate; Also called the limiting frequency






42. Very quiet digital amplifier that produces a series of output pulses with the audio signal coded the same as the width of the output pulses; Pulses are used to represent wave forms and are either on or off; Intense signals have long pulses with short






43. Based on psychoacoustics - these are the basis of frequency analysis for a perceptual codec;






44. Smallest interval measurable by a scientific instrument; Defined by bit rate (sample rate x bit depth)






45. RAM holds in memory audio data before it is transferred to the memory controller; Certain amount of data is processed before large amounts of data are streamed to prevent latency






46. A time regulator that makes all samples and bits to align when working with interconnected digital devices; Basically a signal that all of the digital devices refer to when operating.






47. Voltage -> Dither -> Anti-Aliasing (Low Pass Filter) -> Sample & Hold Circuit -> Successive Approximation/Quantizer --) 100111010 (PCM Audio File)






48. Have odd numbered harmonics






49. Take up half as many bits (50%); Algorithm can keep same quality by lossing the stereo track






50. Measurement at regular intervals of the amplitude of a varying waveform (in order to convert it to digital form); There must be a minimum of 2 samples for each cycle in a waveform