This Vintage Guitar Rig uses horns in combinations with the standard 12" and 15" speakers. Audio crossovers are used to direct the high mids and treble to the horns and the lower mids and bass to the speakers. The crossover frequency between horns and speakers is about 650Hz but with an overlap. This produces a completely unique tone that we were really impressed by. The Rig we're using is a 1969 Impact Midax Dual Purpose with a Goodman (Horns + 12" +15") cab that utilizes a Goodman crossover network. These amazing amps really do deserve more attention. We're playing it today using a Fender Strat and a Gibson Les Paul Custom.