Step 2: Chosing the right combination of components
the first thing that I found were the cones, I found these laying around my house. once you have your speakers open them up to see the cones themself, they should have a power rating and a resistance printed on the back, take note of these.
with the rating on the back of the speakers choose an appropriate amplifier chip, for me I had lot of 4 3.6W 4ohm cones, I decided to put them into two series connected sets, this gave me two satellite speakers each with a rating of 7.2W and 8ohms, the chip I found to match this was the TDA7057AQ, a quick search on farnell/digikey will find one to match your cones.
The amplifier chip will have a maximum input voltage in the data sheet, find the largest capacity battery you can that conforms to these voltage limits, I went with two 4 cell lipo batteries each with a capacity of 2250mAh wired in parallel to make a 4 cell pack with capacity 4500mAh
now you have all the major components worked out you can start the build.