The market is flooded with so many iPod / iPhone speaker-dock systems that you don’t know which ones to consider or what to get. A few of these units that are built by hi-fi names can yield a very good room-filling sound with the deep bass whereas other cheap units just don’t cut it with sound quality.
But you need to be sure that you can use them with devices beyond the Apple iPod or iPhone. Some cheaper speaker-docks have just the slot for an iPod or iPhone and they become useless for those of you who use tablet computers, laptops or Android / WP7 phones.
A line-level input
The speaker dock must be equipped with a line-level audio input of some form. Here, it will be a 3.5mm phone jack or a pair of RCA sockets located on the front or back of the device and this connector may be labelled AUX IN, AUDIO IN, LINE IN or something similar. A few devices use a flylead with an 3.5mm stereo phone plug at one end for quickly plugging your phone or other source in to the speaker dock.
A variety of these speaker docks have a volume control of their own so you can connect an audio-playback device with a fixed output level like a CD player to them yet be able to adjust the volume. On the other hand, this connection would require you to adjust the volume at the source device.
Other connections nice to have
I have raised these other options that may exist in addition to broadcast-radio reception or access to the home network for Internet radio and DLNA-compliant content playback, that may exist in some speaker docks.
A standard USB socket can be nice to have for charging and powering devices like tablet computers or mobile phones on the end of a USB cable. Some setups may also allow playback of content held on a phone or USB memory key through the use of the speaker-dock’s control surface.
Bluetooth A2DP connectivity
This connectivity option works with a large range of mobile devices ranging from some MP3 players through phones and tablets based on the common operating platforms to laptops running Windows, MacOS X and Linux. Here, you have a wireless link from the device to the speaker dock using this standard. This would work well with tablet computers that work as your personal jukebox.
Some speakers like the Bose SoundDock series may offer this as a manufacturer-supplied optional accessory. On the other hand, you can use a third-party Bluetooth audio link that connects to the speaker’s line-level input.
If you looking for that iPod speaker-dock, make sure that, even if you are primarily using it with your iPod or iPhone, it is future proof for use with tablet computers and other devices so you can get more out of the speaker dock.