How to – Dayton Audio OmniMic V2 Precision Measurement System User Manual
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Instructions for special measurements not described on other pages
How to...
Splice two or more frequency response curves together in a graph
This can now be easily done using
Just save the responses to FRD files, then use the "Added
Curves">"Add" menu to bring in both curves, selecting them to have the same color. Configure their frequency ranges so
that one ends where the other starts. If you need to readjust either of them, just select the "Added Curves" menu and
click on the curve name at the bottom of the offered submenu to bring up the properties form for the Added Curve.
Is there a fast way to disable sound output when I'm using the computer to generate test
signals directly from Omnimic?
Yes, simply press on the [Esc] key on your keyboard. Press [F2] to start it again.
Point the microphone
Omnimic is a small capsule, narrow tip measurement microphone and its response is essentially omnidirectional at most
frequencies. At very high frequencies, there is about 3dB reduction in response at 13kHz, as can be easily determined by
making a set of comparative measurements with the mic pointing at and then perpendicular to a high frequency speaker.
Here is a result of such a measurement (showing the effect of perpendicular to directly aimed response):
Align two speakers in "time of arrival" at a listening position
Arrange your system so that the Test Track sound plays out of both speakers you are working with, but with any other
speakers silent. Choose the Frequency Response page and play the indicated track with the microphone set at the
desired position. Set the control that is near the top to "blended" and observe the Impulse Response display. If there is a
time of arrival difference between the two speakers, you should be able to see two impulse peaks. The one to the left
(near the 0 msec point) is from the speaker with the earlier delay time, the other is for the later one. If you have an
electronic delay unit, adjust the delay applied for the earlier speaker so the peaks become superimposed. If you have
more than two speakers you wish to align together, choose the latest (the one making the right-most peak) to be the
reference and delay the others to align to its peak