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. 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






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






3. Single- pin RCA cable or fiber- optic TOSLINK connector used for digital transfer; 75O coaxial - 2- channel unbalanced; 'Consumer' format of AES3






4. Also known as equal loudness curves; Graph that indicates the average ear sensitivity to different frequencies at different SPL levels (as volume increases - these curves flatten out)






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






6. As sample rate is increased more room is created for a smoother slope of the attenuation band because Nyquist limit extends well beyond range of hearing with each increase






7. If a signal is sampled at a rate higher than twice the highest significant signal frequency and at evenly spaced intervals - then the samples contain all the information of the original signal






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






9. Data reduction technique that selectively removes original information in order to significantly reduce the file size; Some data is lost; Files can be reduced up to 99% in size (90% with no perceived sound quality loss); Bit rate effects the perceive






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






11. Roughly around 1 -130 ft/s






12. Decibels Full Scale






13. Allowance of noise floor below that which is required for the final product






14. Rate at which energy is drawn from a source that produces a flow of electricity in a circuit; Expressed in volts






15. Most significant lossless coding technique in current use; Measure of disorder in which long strings of data are represented by short symbols and uses the shortest symbols to represent the most common repetitive audio data maximizing data reduction






16. The act of a frequency swinging back and forth with a steady - uninterrupted rhythm






17. 'Reconstructing' part of digital audio






18. 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






19. Inner ear component that attaches to the stapes and helps to decrease the amplitude of vibrations; Causes the masking phenomenon






20. 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






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






22. (Amplitude Based) Amplitude: Voltage; Quantization; Bit Depth; Quantization Intervals; Quantization Noise; [Signal:Quantization Noise Ratio]; Dither; Dynamic Range






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






24. The frequency above or below which attenuation begins in a filter circuit






25. AES






26. ADPCM; Pulse code modulation that produces a digital signal with a lower bit rate than standard PCM; Records only the difference between samples






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






28. The elapsed time it takes for a packet of data to arrive at its destination; Lagging or pause of an audio signal as digital processing occurs; Can be managed utilizing several forms of 'audio monitoring'






29. Softest sound that can be heard by the average human ear (0 dB)






30. 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






31. Unit of measurement that is equal to one millionth of a meter






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






33. Visual graph that shows how loud a sound is at different frequencies






34. 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.






35. Anytime bit depth is reduced the gap gets bigger so more dithering is required






36. EBU






37. The amount of energy at each wavelength






38. 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)






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






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






41. 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






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






43. 8.75 GB; DS/SL






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






45. Stores only one copy of a stereo signal and assigns it to both channels in order to save 50% of original bandwidth






46. The continuous loss of signal strengths as a signal travels through a medium






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






48. Eight channel digital surround sound system by Dolby






49. 8- in/8- out on one cable; 25- pin D- sub connector






50. Measure of the amplitude of a longitudinal wave