Bose E4 When to repeat the Auto Volume calibration, Auto Volume controls, Auto Volume operation

6.0 E4 System Setup

When to repeat the Auto Volume calibration

You will need to repeat the Auto Volume process if:

•You reset a calibrated zone.

•You physically replaced source hardware.

•You moved a sensing microphone.

•You changed a speaker tap.

•The source hardware has an output control and you changed its setting after you calibrated Auto Volume.

•You have flashed an existing file into a new hardware device in a new installation. The calibration specific to the new installa- tion needs to be performed.

•You upgraded the E4 microcontroller code.

Auto Volume controls

ZONE source input

ZONE sense mic

Gain

Band

pass filter

Auto

Volume

Algorithm

Band

pass filter

ZONE output gain

Auto Volume On/Off states – These selections appear grayed if the Auto Volume function is not calibrated. After a successful cal- ibration, these controls are accessible and you can turn Auto Vol- ume on and off.

Auto Volume Tracking settings – These settings determine the ratio between the background noise and the program material. Once calibrated, the Auto Volume function maintains this ratio. These settings can be changed with some restrictions after cali- bration. See “Changing Auto Volume Tracking after calibrating a zone” on page 58.

	Set “Program	Set “noise
For this type of system	is …” to	by …” to
Background system (music level	less than	1, 3, or 6 dB
is less than room noise level)
Foreground system (music level	equal to	NA
equals room noise level)
Performance system (music level	more than	1 or 3 dB
is greater than room noise level)

Set Up (Auto Volume calibration) button – Clicking this button starts the calibration process. Once calibration is complete, the following functions are disabled for the applicable zone:

•Input Gain controls for all sources routed to the zone

•Source Type for all sources routed to the zone

•Source Assign

•Auto Volume Tracking

•Output Gain controls

Auto Volume reset button – Clears the Auto Volume calibration within the selected zone and enables the functions that were pre- viously disabled. This button is enabled only when the zone is in a calibrated state. See “Resetting a calibrated Auto Volume zone” on page 57.

Auto Volume operation

The Auto Volume function monitors the zone source input relative to the zone sensing microphone input. Based on these two inputs, the Auto Volume function determines if the output gain for the zone must be raised or lowered to maintain the predeter- mined program-to-noise ratio.

•When the Auto Volume function is on, pressing Volume s or Volume t on the Auto Volume user interface will turn Auto Volume off. To turn Auto Volume on again, press the Auto Volume key .

•When you turn Auto Volume off on the user interface, the user interface remembers the volume level setting at the time you turned Auto Volume off. The volume level returns to that level when Auto Volume is turned on again.

•When Auto Volume is on in two adjacent rooms and they are acoustically coupled, the same source must be played in each room. If this is not the case, each zone with Auto Volume will sense the other source as noise and try to overcome that noise. The result would be a very loud system.

Changing Auto Volume Tracking after calibrating a zone

After a zone is calibrated for Auto Volume, the Auto Volume Tracking settings can be changed according to the following table.

If Auto Volume
Tracking is	It can be changed to
more than 3	more than 1
more than 1	more than 3
equal to	less than 1, less than 3, or less than 6
less than 1	equal to, less than 3 or less than 6
less than 3	equal to, less than 1 or less than 6
less than 6	equal to, less than 1 or less than 3

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