Q: I just purchased the Universal Dock along with the Apple Component AV cables. When using the 30-pin connector from the Universal Dock and plugging in the RCAs into the back of my stereo, I’m still having to use the volume control on my iPod. I didn’t want this as I wanted to ensure I’m getting the best quality possible without amplifying my music twice? Is there a setting on the iPod for disabling this?
A: Actually, the Apple Universal Dock does not amplify the iPod output – it merely attenuates it. In other words, the output volume of the iPod is not increased – a volume control is merely provided to allow the user to decrease the volume.
This has created some confusion with regards to the newer Apple accessories and recent-model iPods, as it is easy to assume (incorrectly) from this behavior that the iPod is not sending a fixed line-out signal through the Dock Connector. In reality, however, the line-level that comes out of the Dock Connector is fixed, and with most iPod accessories the volume control setting on the iPod will have no effect. The issue here is that specific Apple accessories such as the Apple Universal Dock and iPod Hi-Fi are able to read the iPod volume setting. In this case, the iPod still outputs a fixed line-level signal via the Dock Connector, but the connected accessory reads the volume setting from the iPod and adjusts its output level accordingly.
As one would expect, in the case of speakers such as the iPod Hi-Fi, this will involve amplification by the speakers themselves (in the same way that a volume control works on any speaker system). The Universal Dock, however, does not include any amplification hardware, and simply acts as an attenuator to allow the user to reduce the volume output level. This is the Dock itself performing this function—the output from the iPod itself remains constant.
Bear in mind that this volume control function only works with very specific iPod accessories—thus far only a few accessories made by Apple themselves take advantage of this iPod-based volume control function. Most third-party speakers and Dock Connector audio accessories will completely ignore the volume setting on the iPod.
For example, if you connect your iPod to an older Dock Connector based audio accessory (such as the fourth-generation iPod Dock), you will discover that the volume control on the iPod itself has no effect—the older Docks do not read the volume from the iPod, and therefore simply ignore it. Further, if you compare the audio output levels between the older Dock and the Apple Universal Dock, you will discover that the maximum volume setting on the Apple Universal Dock is equivalent to the fixed volume output from the older Dock.