Calibration; How Often To Calibrate - TDT Medusa4Z User Manual

Calibration

All speakers have some variation in output across frequencies. When you use a speaker with a
known frequency response in BioSigRZ, you can adjust the stimulus output for these known
frequency characteristics by selecting your speaker from a list in the Stimulus Setup.
Standard calibration files for common speakers and microphones are provided with BioSigRZ
and a speaker-specific custom calibration file might also have been provided with your speaker
(provided on a USB drive in the speaker kit). If a calibration file is not provided for your specific
speaker model or the distance (free-field experiments) or length of tube (closed-field
experiments) is different than those measured for the standard files, you can create a custom
file using BioSigRZ's Calibration tools and a calibration microphone.
The first time you run an ABR, we recommend skipping calibration until after you have been
able to successfully record an ABR response. If the system has not yet been fully tested, using
a custom calibration file can make problems more difficult to diagnose.

How Often to Calibrate

After your system is set-up and working well, how often you calibrate is up to you. Some
researchers prefer to calibrate every day, others prefer once a week, monthly or longer. If you
are using a robust speaker, like the TDT MF1 magnetic speaker, you may choose to calibrate
less often. If you are using a more specialized speaker, like the TDT EC1 or ES1 electrostatic
speakers, you may choose to calibrate more often. If you are new to collecting ABR data,
consider running a calibration check often enough to confirm that you are seeing less than 5
dB variability, then reducing frequency of calibration to something suitable to your protocol and
experiment conditions. We do recommend calibrating anytime your setup (layout or hardware)
has changed.
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