DIY: Making an inexpensive, but good headset microphone
Fitting a microphone capsule onto a telecommunications headset
When you are working on a non-critical project, you do not necessarily need to buy expensive equipment. Indeed, with proper technique, you can obtain really decent recordings with a cheap microphone and a little bit of ingenuity.
Purchase an inexpensive communications headset with an adjustable headband and a flexible boom (e.g., Radio Shack, Plantronics, or equivalent) and an inexpensive, self-powered, omnidirectional miniature lavalier microphone of medium sensitivity (Radio Shack 33-3003 or Audio-Technica ATR35S). Cut off the cord and the small microphone capsule at the end of the boom. Attach the lavalier microphone to the boom as shown in Figure 1. You can use gaffer tape or, preferably, silicone tape, which only adheres to itself, leaving the cord free from sticky residue.
Figure 1. Fitting an inexpensive lavalier microphone onto a telecommunications headset
The total cost of the "starving student version" does not need to exceed $45. The 33-003 (and ATR35S) is capable of recording good spectral detail with a fair amount of confidence that the captured signal can be used reliably, at least for basic acoustic measurements. This microphone is self-powered and has an unbalanced 1/8-inch connector, so it can be used with a variety of consumer-level recorders (e.g, Tascam, Olympus, Marantz, Edirol, Zoom, etc.). Figure 2 shows a finished DIY headest with the RadioShack 33-003 lavalier microphone.
Figure 3. RadioShack lavalier microphone in a DIY headset
Figure 3 shows a spectrogram of the Polish phrase "czarna krowa" acquired with the 33-003 microphone in a headset configuration. Note good spectral detail with little unwanted noise and a smooth frequency response with no evidence of proximity effect.
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Figure 3. spectrogram of the Polish phrase "czarna krowa" acquired with the 33-003 microphone in a headset configuration
Similarly, Figure 4 shows a really decent FFT of the vowe /a/ in "czarna" with no evidence of smearing and a realistic frequency envelope.
Figure 4. FFT of the vowe /a/ in "czarna"