1 LingDy 10 Feb 2012 TUFS, Tokyo David Nathan Endangered Languages Archive Hans Rausing Endangered Languages Project SOAS, University of London Audio Theory and Practice for Language Documentation

2 Questions  have you recorded audio?  have you published audio?  what else have you done with your audio?

3 Questions  you buy a recorder for $x. A matching microphone should cost: (a) 3x (b) 0.8x (c) 0.3x (d) 0.1x (e) relative cost is irrelevant

4 Question  Digitally recorded audio is better quality than analogue recorded audio because: (a) digital microphones are more accurate (b) digital formats are more accurate (c) digital equipment is newer (d) digital formats capture more information (e) no, digital audio is not better than analogue audio

5 Big questions  what are we actually recording?  what/who is it for?  what is the role of audio in language documentation?

6 Epistemology for audio in documentation  an audio recording is made in order to be experienced by a human listener  a recording conveys what a human listener would experience at a particular location in an event setting  documentation goals define recording methodology  a recording should capture spatial information  metadata about the recording and the recording setting are required for full interpretation  ethical recording respects speakers and honours their contribution through your effort and skill

7 Evaluating recordings  accuracy: how well is the signal captured, as true to its sources and without distortion?  intelligibility/information accessibility: can the desired content be identified?  signal vs. noise: is the ratio acceptable? can the focal source be separated from all sources of noise?  listenability/comfort/aesthetics: is it easy on the ears? will it be debilitating to listen to for an extended time?

8 Evaluating recordings  localisation of sources: is enough spatial information captured?  separation of noise: can all sources of noise be separated?  representation of environment: are the acoustic properties of the recording space appropriately represented?

9 Evaluating recordings  content (identity, performance, uniqueness, coverage): were the right people recorded doing the right things?  editability/repurposeability: is the recording suitable for turning to relevant purposes?

10 Recording audio  making it is both art and science  a critical and ethical responsibility  strongest relationship to communities  it’s not necessary to record everything, but it is necessary to record well

11 SIGNAL & NOISE

12 Evaluating recordings  signal  noise  signal to noise ratio  listenability (eg comfort, consistency)  fit for purpose

13 Evaluating recordings  audio professionals use their human ears as evaluator of audio quality and value, while many linguists (mistakenly?) look to formats, spectrographs, wave-forms, analyses etc  44.1 KHz, 24 bit

14 Signal - what you want  content  contextual and spatial information  fidelity  comfortable to listen to

15 Noise - what you don’t want  from environment:  near: people, animals, activities  far: traffic, generators, planes  machines: refrigerators, fans, computers  not hearable: mobile phones, electrical interference  acoustic: reflections/resonance

16 Noise - what you don’t want  generated by (unwanted parts of) event  shuffling papers, clothes  table banging  backchannel from interviewer  equipment handling, especially microphones and cables (and recorders with built-in mics)

17 Avoiding handling noise  use stands and cradles etc

18 Noise - what you don’t want  generated by equipment  wrong input levels  circuity noise (cheap or incompatible)  compression loss or distortion  ALC/AGC effects (pumping)  video camera motors

19 Evaluating environment/situation external environment  access  electricity  external noise sources

20 External noise sources examplepossibilities for dealing with it trafficinvestigate, record in quiet time face away use damping materials childrenget them involved show something to satisfy curiosity animalschoose time of day weather (wind, thunder, rain etc) use dead cat; wait; reschedule  see also General principles

21 Dead cat

22 Close-up noise sources  machines examplepossibilities for dealing with it refrigeratorpre-survey what comes on intermittently turn off relocate motors, switchingmonitor fansmonitor, dead cat (windshield)

23 Dealing with noise sources  be prepared and aware  seek collaboration  monitor  use or modify room acoustics  location  direction  surfaces  reflection  absorption  isolation

24 Utilising room acoustics  location  away from doors, windows, traffic areas  direction  face away from noise sources  reflection  avoid parallel surfaces  surfaces  avoid hard smooth surfaces  choose or create soft or rough surfaces  isolation  find an ‘’airtight’’ place

25 When is a noise not a noise?  When it is part of the content, for some interpretation of the event John Cage performance

26 PERCEPTION & PSYCHOACOUSTICS

27 Audio perception/psychoacoustics  a human listener has:  location, orientation in a physical setting  two ears - incredibly sensitive  a brain/mind  the mind selects from various sources of sound and other sensory information, using long- and short-term memory  listening is actually a “hallucination”

28 Psychoacoustics and recording  microphones don’t have a mind: they can't distinguish wanted from unwanted sound  microphones don’t have “edges” like camera lenses

29 Psychoacoustics and recording  the recording process removes acoustic information  if you only care about transcription, then you are going to throw away over 99% of the acoustic information! real world record acoustic phenomena represent (some) linguistic components derive data

30 Implications for recording  typical recording methods are unscientific!  … so what should we do?

31 Implications for recording  plan and manage recording  goals  equipment  preparation  environment and setup  sources  changes and actions  settings

32 Implications for recording  why is it important to record spatial information?  what other information (acoustic or non- acoustic) do we need?

33 “Sound stage”  spatial information is an essential part of audio  we are amazingly attuned to it  we should record in stereo

34 “Sound stage” ... or in ORTF (binaural)

35 MICROPHONES

36 Microphones and audio quality  microphones are the greatest determinant of audio recording quality  selection of appropriate microphone(s) for the task  placement and handling of the microphone(s)

37 Microphones in the digital era  microphones in the digital era  recorder quality has increased but prices decreased  microphones have become comparatively more expensive  why? microphones are analogue devices!

38 Microphone types  principle: dynamic vs condenser  directionality: omni, cardoid, and shotgun  spatiality: mono, stereo, binaural

39 Microphone physical principles  dynamic  generate signal from sound pressure  more robust, less accurate  used for musical and live performance  condenser  more fragile, sensitive and accurate  need power source - battery or phantom power  in general, use condenser microphones for language documentation

40 Omni  lavalier or tie-clip microphones are typically omni-directional

41 Microphone directionality - omni omni-directional

42 Cardioid  many “standard” handheld microphones are cardioid units

43 Microphone directionality - cardioid cardioid

44 Shotgun  shotguns are good for quiet sources, in some noisy environments, and for video work

45 Microphone directionality - shotgun shotgun/directional/hypercardioid

46 Stereo microphones  spatial information is an essential part of audio

47 Full “sound stage”: ORTF

48 Simulating ORTF with 2 cardioids 17cm 110°

49 Microphones - quality  generally, you get what you pay for  each model has its own subjective colour  decent microphones for language documentation fieldwork cost from £120 to £300

50 Reputable makers - include  AKG  Audio Technica  Beyerdynamic  Røde  Sennheiser  Shure  Sony

51 Microphone placement

52 Microphone usage principles  where should the microphone be?  in general, about 20cm from the speaker’s mouth  the inverse square law is your friend...

53 The inverse square law

54 The inverse square law

55 Using the inverse square law  if you have noise sources, maximise the signal to noise ratio by:  placing the microphone as close as possible to the signal source  placing the microphone as far as possible from the noise source

56 AUDIO WORKFLOW

57 Audio workflow who/what/where /why/how do you want to record? contact people audio training budget, research, and buy equipment assemble, test, practise Before you go

58 Audio workflow transport safely check environment, situations, permissions make test recordings local training & collaboration On site, before recording

59 Audio workflow record! monitor! collect metadata (label)check quality monitor Sessions

60 Audio workflow (label)check quality backupadd information (metadata, metadocumentation, transcriptions, annotations, etc) After sessions

61 Audio workflow … send samples to archive add information (metadata, metadocumentation, transcriptions, annotations, etc)... package and send to archive Later

62 CONNECTIONS

63 Microphone connections  plugs  cable types  cables for stereo/mono, multiple  wireless  power sources for condenser microphones - battery or phantom power  see

64 Microphone connections  minijack/miniplug (fragile)  RCA/phono  1/4 inch (headphone)  XLR (Canon)

65 XLR  professionals always use them  electrical contact is independent of the physical connection  latching is independent of the electrical contact  you can use XML-to-miniplug cables or converters for recorders with miniplug inputs

66 IMPLICATIONS FOR VIDEO

67 Implications for video  video captures spatial information – but so does audio  so these need to be co-ordinated  match audio microphones and pattern to video framing and events  camera location is often not the correct location for microphone  get L & R channels correct!

68 Implications for video  video formats for audio component may be compressed – how much does this matter?  don’t sacrifice audio quality for video  should we record audio separately or not?

69 IMPLICATIONS FOR METADATA  document the goals  document the environment  document the layout/setup e.g. directional language  use: diagrams, photos, oral and written descriptions (e.g of relationships)

70 End