After having solved this problem I added the coil, as a low pass filter, and the 11 uF bipolar capacitor as a high pass filter. Both filters work great with low frequencies on the low pass filter and high frequencies on the high pass filter. The coil is the same that I used in experiment 28 and the bipolar capacitor was made of two 22uF electrolytic capacitors.
Next I'll fit the speaker in a shoebox and create a waveform with a 555 chip as an input for the audio amplifier (instead of the ipod).
|Overview over the experiment with on the left the power supply, in the middle the ipod and on the right the breadboard.|
|A top-down view of the 4-inch speaker (top), breadboard and coil (bottom)|
|Close-up of the breadboard with on the left the TEA2025B amplifier.|