a horn type will give the most volume. Powersource from 9 to 12 volts DC. A 9 volt ... touch) between point 4 and point 3 (the power connection). 3. Connect power to point ... a horn type will give the most volume. Powersource from 9 to 12 volts DC. A 9 volt ... touch) between point 4 and point 3 (the power connection). 3. Connect power to point ...