The combination of an older version of Microphone, order code MCA-BTA, $44 (shipped before August 2013), and LabQuest 2, order code LABQ2, $329, will result in waveforms that exhibit excessive high-frequency noise. If an FFT is performed, the noise peaks above 3000 Hz. The noise is only visible when viewing low-amplitude waveforms, such as from a tuning fork.
Unfortunately, there is no workaround. If you have both LabQuest 2 interfaces and Microphones made before August 29, 2013 that show excessive noise, Vernier will replace the older Microphones with newer versions that are resistant to the interaction with LabQuest 2. Contact Vernier technical support to request an exchange.
We have also had reports of the same effect showing up when these Microphones are used with the TI-Nspire Lab Cradle TI-Nspire Lab Cradle, order code TI-NSLABC, $145
Older Microphones all work well with LabPro, order code LABPRO, regardless of labeling or age. The noise is created by an interaction between the Microphone and LabQuest 2.
Microphones made after Sept 2011 work well with the original LabQuest. See:
TIL 2436: LabQuest (original) and LabQuest Mini: Readings from my Vernier Microphone are very noisy.
TIL 2274: How can I generate a clean sine wave output from a LabQuest?
TIL 662: What is the best procedure to get a clean sine wave when using a tuning fork with the microphone?