Onkyo TX-NR 838 Manual page 72

Specify the distance between each speaker and the listening position.
Back Left
Default Value: 7.0 ft/2.10 m
Specify the distance between each speaker and the listening position.
Surround Left
Default Value: 7.0 ft/2.10 m
Specify the distance between each speaker and the listening position.
Subwoofer
Default Value: 12.0 ft/3.60 m
Specify the distance between each speaker and the listening position.
Height Left
Default Value: 9.0 ft/2.70 m
Specify the distance between each speaker and the listening position.
Height Right
Default Value: 9.0 ft/2.70 m
Specify the distance between each speaker and the listening position.
In the following cases, the settings for "Speaker Distance" cannot be
changed:
– The speaker is set to "No" or "None" in "Speaker Configuration".
– "Powered Zone 2" is set to "Yes" and also Zone2 is set to on.
Default values vary depending on the regions.
Level Calibration
Adjust the level of each speaker with the built-in test tone. Settings are
automatically configured if you use the Automatic Speaker Setup.
Front Left
Default Value: 0 dB
Select a value between "-12 dB" to "+12 dB". A test tone will be output