Apple iPod Hi-Fi (User’s Guide) - Manual (Page 19)

Chapter 3 Using Your iPod Hi-Fi 19
If you connect another audio device that has volume controls to the audio input port,
such as a stereo receiver, you can also change the volume using the other device.
Experiment to see which volume level sounds best when using the device with your
iPod Hi-Fi.
To change equalizer settings:
m If you’re playing music through an iPod, change the settings on the iPod. Choose
Settings > EQ and choose an equalizer preset.
m If you’re playing music through a device connected to the audio input port, change
equalizer settings on the device, if possible. See the documentation that came with the
device.
To increase the bass or the treble:
With some newer models of iPod, you can also set your iPod Hi-Fi to increase the bass
or the treble. You’re able to adjust this setting if you see a Speakers item in the main
menu when you connect your iPod.
m Choose Speakers > Tone Control, and then choose Treble Boost, Normal, or Bass Boost.