This information pertains to the original LabQuest.

If you have LabQuest 2 or LabQuest 3, see this article.

Units of the Vernier Microphone (MCA-BTA), produced between April of 2007 and August 22, 2011, may exhibit a conflict with original LabQuest and LabQuest mini. Affected units may display noisy graphs when the sound source is of a low amplitude.

To diagnose this issue, collect a sample for 0.03 s at 10,000 Hz. Then create an FFT graph. Affected units have visible noise around 3,000 Hz, which will show up as a peak in the FFT graph.

This noise is not present in the same units when connected to LabPro.

Microphones shipped on or after August 23, 2011 can be identified by a black product tag with white print near the BTA connector. Units with the product tag should not exhibit the noise or the 3,000 Hz peak.

Microphones shipped after June 15 2012 have a white label with black print near the BTA connector. These microphones also are improved for use with LabQuest 2.

If your microphone has the 3 kHz noise symptom, contact Vernier technical support.

See also:
How do you change the bin size of an FFT in Logger Pro?
Data collected with LabQuest Mini are very noisy, or triggering fails.