How can I increase the maximum speaker volume?
There is an app which can do it for you...
Try the free one first, and if it works, then buy the full version :)

Free: https://market.android.com/details?id=com.FREE.android.lvh&amp;feature=search_result

Payed: https://market.android.com/details?id=com.TEST.android.lvh&amp;feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5URVNULmFuZHJvaWQubHZoIl0.

Have a great day :)