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The Soda Bottle/Cup Speaker-Experiments

This page describes some experiments you may wish to conduct with your speaker.

The diaphragm:

Some of the most simple experiments you can do are with the diaphragm.  It is very important to make sure that the diaphragm is free to vibrate.  When you tape the diaphragm in place, make sure it is not too tight.  You can try different materials such as paper, plastic wrap, an old rubber glove......  In each case be careful when you attach the voice coil.

The bottle:

The cone shaped part of the bottle also acts as a resonating chamber.  The plastic should have holes in it and not completely sealed.  You can try various bottle sizes.  A bleach or large juice bottle will sound different than a small water bottle.  You will also find that you can place the speaker inside the remaining (cylindrical) part of the bottle.  Listen to some music and then move the speaker in an out of the bottle.  You will notice the tone of the music changes.  As you move the speaker closer to the bottle you might notice the bass part of the music will get louder. 

Frequency response:

You can use a function generator and a sound level meter to map out the frequency response of the speaker.  There are several electronics companies that sell inexpensive sound level meters.