Sony TMR-BT8IP Operating Instructions Manual page 15

 T ip
You can control the volume on the Bluetooth receiving device.
(The volume of the iPod is not changed.)
Notes
 Even if you control the volume on the iPod, sound from the Bluetooth receiving
device will not change.
 If this unit and the Bluetooth receiving device become out of range and the
Bluetooth connection terminates, repeat the procedure from step 1.
 Playback through a Bluetooth connection may cause noise, sound break, or
playback speed change depending on the location and the usage (page 17).
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