Pacific Accessory Corporation's Tri-Way TM-100 is a simple device, but how complex does it need to be? This crossover unit is designed to work with a Tri-Mode or Tri-Way compatible amplifier, using the amplifier's bridged output.

With the TM-100, users are able to wire a pair of stereo speakers in addition to a subwoofer from the output of a two-channel amplifier. It uses a fixed crossover point of 100Hz with a 12db/octave slope that filters just the low frequencies to go to the subwoofer. The same frequency (100Hz) is used to filter all frequencies above that to the main speakers, although this filter has a 6dB/octave slope.

The maximum power that the TM-100 can handle is 250 watts (average) per channel. Instead of input and output jacks, the TM-100 has wires that connect directly to an amplifier's speaker output and three pairs of wires that lead to the speakers and subwoofer.

Anyone seeking an affordable and simple way to add a subwoofer while using a two-channel amplifier should consider the PAC TM-100.