Sometimes when taking measurements, you might experience a low or poor signal-to-noise ratio. This means that sound recorded by the microphone is too filled with background noise for our software to differentiate reliably between the measurement sweep—the signal, a useful sound—and the noise—a useless sound. Presence of low SNR requires a new measurement to be taken.
Here are some common causes and solutions to signal-to-noise ratio problems.
- Background or ambient noise in the room is too loud.
- Sudden noise occurs in background.
- Microphone gain is too high (too much digital or ambient noise is picked up).
- Older software used an inferior method for picking signal from noise.
- A nonexistent speaker is recognized by Dirac Live.
- Turn off or remove all equipment and machinery that could be causing excessive noise in your space, including air conditioners, driers, refrigerators, and pets, as well as close all windows or doors.
- Decrease microphone gain relative to master output.
- Note: It is important to find a balance between the two. Master output should never be high enough to cause discomfort, nor should microphone gain be high enough to cause SNR problems.
- Update the Dirac Live software to its latest version, which features better SNR calculation.
- Inspect the graph after a successful measurement to ensure that there is not unexpectedly high response at a particularly low frequency. This may be caused by background humming or noise (like from a refrigerator).
- Make sure, during Volume Calibration, that all your speakers are accounted for. If additional speakers appear that are not connected to your system, then trace the signal path and make sure your Dirac-enabled device is not erroneously reporting a speaker that doesn't exist.
- Example: In the case of a home AVR, make sure that all speakers are recognized by the device firmware. Enable only the exact amount of subwoofers and surround speakers. If your system reports too many speakers, Dirac will try to calibrate for a speaker that cannot produce a signal, thereby generating a SNR issue.