Planning for Field and Booth Recordings

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The following is a guideline for choosing equipment. If you'd like to check out any equipment, please make sure you're familiar with the equipment checkout policies and have followed all necessary steps. To reserve equipment, please go to the online reservation system.


Microphones

A useful guideline on choosing microphones for phonetic research:

https://ajslp.pubs.asha.org/epdf.aspx?doi=10.1044/1058-0360(2010/09-0091)

Some important specs to consider:

  • frequency response (20 - 20,000 Hz is the standard, should be no less than 50-10,000 Hz), should be as flat as possible (no more than +-2.5 dB)
  • SNR (signal-to-noise ratio), the higher the better, ideally should be more than 30 dB
  • omnidirectional vs. cardioid (cardioid mics less prone to background noise, but are subject to proximity effects, so you have to make sure you place the microphone at a distance prescribed in manufacturers' user guides)
  • condenser vs. dynamic (condenser generally better, but require Phantom 48 V power, so check that your preamplifier is capable of providing this power)
  • dynamic range: shouting can reach up to 135–145 dB for head-mounted mics, so if you're recording very loud settings/singing, you need a mic that can faithfully represent up to 145dB (Max. SPL for 1% / 3% above 145dB). Generally, such mics are rare and if you're recording normal speech, lower values are acceptable
  • head-mounted vs. free standing microphones (head-mounted have the advantage of being less prone to background noise, but they can pick up various artifacts, so make sure you place them on the side of the mouth)
  • XLR connector (you need a converter, if mic has mini-XLR). Other connectors are not as appropriate

Field

Number of Speakers

How many speakers will you be recording in a sitting? One or multiple? If multiple, do you need each speaker to be on their own channel (you most likely do).

Amount of Background Noise

How noisy will the background be where you are recording? If not possible to record in a very quiet place, figure out when your recording environment will be the least noisy (Sunday morning?) and do your recording then if possible.

Distance from the Speaker

How close do you need the speaker to be to the microphone? First, check specification for each microphone. Cardioid microphones have "proximity effect", so you need to place the microphone so that the frequency response is a s flat as possible (specified in technical specifications for each microphone). Omnidirectional microphones usually do not have this problem (but check specs, because some omnidirectional mics, especially those for which you can choose between cardioid and omnidirectional patterns likely have the proximity effect as well). You might start with about 10". The ideal recording distance depends on the speaker and how naturally loud vs. quiet they are. It is best to take the time to make a test recording, recording a variety of sounds, including ones which might generate a great deal of airflow, like stop release bursts, and then look at the recording. You might think that the closer the speaker is to the microphone, the better the signal to noise ratio will be. But you may record some distorting puffs of air that way. Even the speaker breathing between words can introduce an unwanted low frequency sound wave in the signal you are trying to record. On the other hand, the farther the speaker is from the microphone, the less the signal to noise ratio, but for a speaker with a booming voice, they may need to be much farther away than 10".

Booth

Number of Speakers

How many speakers will you be recording in a sitting? One or multiple? If multiple, do you need each speaker to be on their own channel (you most likely do).


Distance from the Speaker

How close do you need the speaker to be to the microphone?