This is a 2.1 (stereo + mono bass channel) amplifier that takes a digital signal, coax or optical. The crossover frequency between stereo channels and bass can be set from 80 to 360hz or bypassed (requires remote which is not included). The amplifier can also be used as a stereo amplifier without crossover and without using the bass channel. The crossover is a preset filter in sta320, and it's 2nd order low pass and 1st order high pass. The crossover is default set at 80hz, also when the amp is in 2.0 mode.
New version (september 2014) comes without remote but with remote learning feature. You can use any 38kHz (RC5 code) remote that you have to control this amp. Details on how to set the remote in the manual.
The remote is required to: set crossover frequency, EQ, dim display. Without remote you can: adjust volume, switch input channel, set to standby.
Temporary settings (volume level, channels) is saved on power down. However this only works when power is cut instantly. if the ddx is powered by a SMPS, then the voltage will fade away, and the settings will not be saved.
When learning remote keys, the power should be cut instantly the first time after learning the remote keys. After the settings is saved, it will remember them also if power fades away.