You can also increase the volume by doubling your speaker number per channel. For example, you can connect two speakers per channel. ( usually 1 per channel ) If you have a 7 channel amp, you just add 1 more speaker per channel and you can have 14 channels total by using this method to increase overall volume. But, this method put heavy stress on your amp. Make sure your amp can be abused this way. I also abuse my amp this way. and it smells hot from the heat sink!! But it sounds awesome