Not to good on nice bass gear so I come to ask. My bassist has a 2x15 cab, and either fried the head or the speakers. We think it is the speakers. The amp is a GK700RB not sure which series, He uses a Spector bass not sure which model and we play metal. Looking for suggestions on what speakers to get to throw in the cab. Will probably go used and hopefully find a good deal, but what are some good 15" for metal?