Construction: The SPX-177As have one of the most sophisticated crossover networks available, including customizable phase and off-axis compensation circuits. The available jumper settings offer 60 unique and useful combinations. The crossover network has a blue plastic base with a clear plastic cover that can be removed for making jumper adjustments. High quality components are used in the crossover network, including Low-Tolerance Resistors, Heavy-gauge Gold-plated OFC Circuit Board Traces, and OFC Copper Air Core Inductors.
Bi-Amplifier Inputs: The SPX-177A speakers can be connected by a single input to the crossover or Bi-amplified. The crossover's default connection is a single input, using two solid jumper bars to "link" the crossover input signal to the tweeter output terminals. To bi-amp the speakers, you will need to remove the jumpers and connect the woofer and tweeter input signals separately.
Advanced Phase Compensation: Because it is difficult to achieve perfect speaker placement within a vehicle, many times the woofer and tweeter are mounted "out of phase", causing some signal degradation. The crossover network of the SPX-177As uses two sets of jumpers to achieve "phase linkage" between the woofer and tweeter, producing a seamless blend or transition between the two drivers. The setting of the jumpers is dependent upon individual driver placement in relationship to each other, and their relative distance to the listener. The jumper setting options are as follows:
WF-LP (Woofer Low-pass): Blend A, Blend B
TW-HP (Tweeter High-pass): HP-1, HP-2
Off-Axis Compensation: The individual frequency responses of the woofer and tweeter can be changed in order to compensate for the natural roll-off that occurs when the listener is positioned off-axis. These changes are accomplished by the position of individual jumpers for the woofer and tweeter circuits. In addition, the tweeter jumper also serves as precise level adjustment. The jumper setting options are as follows:
WF (Woofer): 0°, 20°, 45°
TW (Tweeter): 45°(+2.5dB), 20°(+1.5dB), 0°(+0dB), -2dB, -4dB
Tweeter Protection Circuit: This built-in protection circuit includes two incandescent bulbs (visible through the clear crossover cover) and limits power to the tweeter when the "danger" threshold is exceeded. This method of protection in inaudible because the circuit simply limits power and does not shut the tweeter off.
Crossover Dimensions: The dimensions are: W=7.086", H=1.844", D=5.264"
