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. Based on Full Scale (dB/FS); -6dB represents a loss of one bit so account for this when calculating






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






3. VBR; Most common & best data reduction technique; Codecs that encode data by determining how dense or sparse areas of the audio are; Can result in buffering issues






4. Having a repeated succession of waves or curves as in a sound waveform






5. 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)






6. Algorithm uses matrix of a mid/side microphone pair to determine a side signal & that signal is reduced then distributed as code in stereo






7. Overtones that contribute to the timbre of a sound and make up a complex waveform's physical characteristics






8. ABR; Codecs that encode data by determining how dense or sparse areas of the audio are while also keeping bit rate within specified limits to avoid rebuffering






9. Same as 'aliasing'






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






11. 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






12. 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






13. Number of bits per second processed when sampling sound; (Sampling Rate x Bit Depth) = Resolution






14. Removes high frequency images and noise and smoothes the stair case output coming from of the sample and hold circuit; Also called a SMOOTHING FILTER






15. The number of compressions or rarefactions in one second; The higher the frequency the more compressions & rarefactions per second; Measured in Hertz






16. Process of building a complex tone by starting with the fundamental frequency and adding pure tone harmonics






17. (Time Based) Frequency: Aliasing; Anti-Aliasing Filter; Sample Rate; Nyquist Limit






18. Signal that uses variable voltage to create continuous waves resulting in an inexact transmission






19. AES






20. A digital filter's time domain output sequence when the input is a single sample is input






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






22. Data reduction technique that does not effect quality of original audio; No effect on original quality; Typically around 50% reduction; Exact reconstruction of digital code for the audio signal






23. 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






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






25. Found that aliasing was always a problem no matter how fast you sample; Less data recorded but more accurate; 2 samples per wave length.






26. In order to play multiple channels at one time data is buffered as read to disk; Latency happens between play command & beginning of playback






27. Leaving space at beginning and ending of song for data crunching during mastering; Last step in mastering process






28. 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);






29. 16-Bit; 44.1 kHz; PCM; Stereo






30. The amount of energy at each wavelength






31. Toshiba developed digital audio interface utilizes fiber optics as a transmission medium.






32. 8.75 GB; DS/SL






33. Number or variable that represents the number of times the base of a power is used as a factor; Defines magnitude






34. More aggressive lossy data reduction techniques that require further manipulation of the stereo field; Examples are 'Intensity' & 'M-S'






35. CobraNet; EtherSound; Dante; AVB (currently under development)






36. Specific set of instructions for carrying out a data reduction technique that determines how to 'save' binary data information efficiently






37. The ability of a digital system to perform complex DSP without running into problems with overflow or loss of resolution






38. The frequency range that is allowed through a filter






39. 15.9 GB; DS/DL






40. Defines the number of sample per second taken from a continuous signal to make a discrete signal; Governs the frequency response of digital audio






41. A sample- by- sample operation on two signals






42. 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.






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






44. Roughly around 1 -130 ft/s






45. Reduces the percieved distortion due to quantization error; Low level white noise source is introduced to make the profile of the quantization 'noise' more irregular; Useful when reducing the number of bits per word in a signal (i.e. when converting






46. Amplitude meter that takes the square root of all instantaneous amplitudes and averages them to find a mean and squares that value; Useful with particularly complex waveforms






47. ADAT Optcal; 8- in/8- out on two cables; Fiber- optic - TOSLINK connector






48. Branch of psychology concerned with the subjective perception of sound






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






50. Each bit in the bit depth is equal to a _____ increase in dynamic range