The
Collins Guide to
Speaker Care
Page 3
Now the slightly tricky bit. Find the person with the smallest hands in your household and get them to gently 'massage' the rubber support that surrounds the speaker cone. Wearing gloves is also recommended so that oily deposits are kept to a minimum.

After just a few seconds you should start to hear a difference: Where the sound was once thin you will notice a certain 'edginess'. Where it was too bright you will notice subtle overtones that were barely audible before. More than anything else you will will find that the sound is now more exciting than ever!
What you are aiming for is shown below, and should only take an experienced person a few minutes to complete.

All modifications (c) Ben Collins 2000