Troubleshooting – Dayton Audio OmniMic V2 Precision Measurement System User Manual
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Troubleshooting
Listed are answers to some questions that may arise.
There is a message with a yellow background telling me "Check for Correct CD Track!".
Most tests with OmniMic (other than "SPL/Spectrum" and "Oscilloscope") require particular CD tracks
to be played on the system that you are measuring. The tracks contain test signals necessary for the
OmniMic software to do its analysis. You cannot substitute other test signals. For example,
although the "Pseudo Noise" (CD Track 1) signal sounds like pink noise, it is actually very different
and use of pink noise in its place will not produce a useful result. The proper CD track to play for any
OmniMic test is displayed at the top of the OmniMic screen. If you have lost your OmniMic test track
CD, contact your Dayton Audio dealer or check
for a replacement.
In most cases, it is also possible to play copies of the CD tracks that have been recorded to other
media, see
I get messages saying that my "Control Panel" settings are not correct for OmniMic.
This can happen in Windows VISTA or Windows7 (and possibly in later Windows operating
systems). For proper operation of OmniMic at higher sound levels, you must make sure in later
Windows versions that the system recognizes the microphone as a 2 channel microphone (the
second channel is used for handling higher signal levels). The message gives specific directions for
making the proper settings. The exact procedure may change in later Windows versions, so you may
have to manually open the Control Panel and locate the pages for making the needed settings. The
settings may need to be done for each of the computer's USB ports that might be used with OmniMic.
The top of the OmniMic window shows the message "OmniMic not found".
This indicates that the presence of the OmniMic is not detected. OmniMic hardware must be
attached to a working USB port on the computer for the program to be able to make measurements.
Try using a different USB port on the computer and make certain that the blue indicator light (at top or
back of the Omnimic) is illuminated. Unplug any other USB-based audio hardware from the
computer, and if necessary try rebooting the computer. Please note that OmniMic cannot be used
with Windows98, WindowsME, Macintosh OSes or under Linux or Linux/Wine.
The graphs of frequency response (or other measurements) is always changing at lower
frequencies.
This is probably because the test signal is not being played loud enough to overcome the background
noise. Try playing the test CD louder or moving the microphone closer to the speaker(s). For many
systems, the response at lower frequencies may be insufficient to overcome the noise.
Impulse response and phase traces seem to jitter left and right during measurements.
This is normal to a small degree. Because OmniMic doesn't know when the test signal arrived at the
loudspeaker, it can only refer phase and time displays to the largest peak of the recovered impulse
response shape, which can vary with responses that have have multiple peaks of similar level.
Harmonic Distortion plots don't seem to make sense at weak frequencies.
This again results from insufficient test signal level arriving at the OmniMic relative to noise. High