OK! I need a little help and advice from you speaker experts. I'm looking at pairing another 1x15 cabinet with my current Ampeg SVT-15E. It has a sensitivity rating of 98dB with a maximum SPL of 123 dB. How close would another cab have to be to these specifications without having a problem with a mismatch that actually matters? Do I need to be right on, or can I be a little off one way or the other. Thanks!