The APBX 8 R loaded enclosure was developed with reflex loading, with tuning designed to concentrate SPL in the lowest frequency range. The aim was to exploit the natural boost in output found in most cars below 60 Hz known as “cabin gain”. The 8-inch single 4 Ω voice-coil subwoofer has a powerful motor that maximizes efficiency in combination with the AP8.9 bit amplifier. The low-resonant frequency of the subwoofer, matched to the reflex enclosure keeps excursion low within the entire audio spectrum, allowing also the use with a pair of AP4.9 bit / AP4 D bridged channels, capable of delivering 260 W rms.

The APBX 8 DS loaded enclosure provides the highest performance/ size ratio. For this purpose an 8.5 lt. sealed enclosure with a 4+4 Ω dual voice-coil configuration was adopted to exploit the full power of an AP5.9 bit (paralleling voice coils for a 2-ohm load) or with two pairs of AP8.9 bit bridged channels (one bridged pair of channels to each voice coil). The speaker’s high excursion capability allows the use of the proprietary BASS BOOST of AP bit amplifiers to make use of all the available power for rich and dynamic bass.