I am currently testing the Up2stream AMP v4. Very good results so far.
I have noticed that I can build a 2.1 system (2 speakers + 1 active subwoofer) by using the analog mono output (XOUT). In ACPWorkbench there is a Mono Channel EQ in Effect List 1. This way, I can implement a crossover between the main speakers and the active subwoofer. So far so good.
I have also noticed that I can have a stereo analog output instead (with L and R channels). I could use such a setup to build a 2.2. system (2 speakers + 2 active subwoofers). My question is: What happens within the DSP? Will ACPWorkbench recognize that I use both channels and provide “L” and “R” channels for analog out? If not, will the Mono channel EQ effect the “L” and “R” channels identically? Or will it have no effect?
Basically, I see great potential to build a very powerful system this way with the crossover set relatively high (between 100 and 150Hz). The subwoofers would serve as external bass modules.
I have already experimented with the subwoofer output of an A50+. This output is mono and used a Y-cable to connect 2 active subwoofer. DSP worked with Mono channel EQ. However, this way I cannot get stereo bass.
The amp chip on AMP V4 used the L/R signal as input in stereo mode, and X signal in mono mode. If I understand well, it’s not possible to build a 2.2 system, as there’re only 3 output channels on board, and the X channel have mixed data of L+R.
my subs have own controls for volume and crossover. However, I wanted to realize a digital crossover and a proper equalization with ACPWorkbench. When I understand it correctly, I can (only) do that for the subs with the mono channel. My setup would be the following:
main speakers L+R, implement a digital highpass, e.g. 120Hz and equalize both speakers individually in ACP Workbench
2 subwoofers in mono mode using a Y-cable, implement a digital lowpass, e.g. 120 Hz and equalize the output of both subwoofers using the mono channel in ACPWorkbench
after that, I could use the main equalizer in ACPWorkbench to create different voicings with High and Low Shelves (e.g. for low level and for high level listening). However, this would (only) make sense with a remote control. Sadly, the 4stream App does not provide access to such settings (please correct me, if I am wrong).
from the photo on the website, I see that are also L/R outputs availabe (see picture). From there I should be able to wire to Cinch out connectors, right? However, I assume that the limitation is in ACPWorbench which is not supporting to equalize these channels separately. Would the mono channel in ACPWorkbench effect the L/R outputs? And am I correct, that the mono channel in ACPWorkbench effects the mono XOUT?
Thanks, that helps and that is what I expected. Thus, stereo subwoofers are not possible the way I wanted to implement it (with separate L/R DSP). However, this limitation is not huge. I can still drive 2 subwoofers with the mono signal and eq them together.
Can you please share more about your statement " by using the analog mono output (XOUT)". How are you connecting?
I read through this thread and I see that label as one of the “DAC Output” pins. Are you using some sort of converter or does this output the RCA/Line level type output that can be sent to a powered sub?
I am not using it yet, but as far as I understand, the analog mono output (XOUT) is an analog signal which you can use to like any RCA/Line level type output. Also stereo would be possible. However, if you want to use ACPWorkbench to EQ you only have the (combined) Mono Channel. I do not know, if EQs in this mono channel will effect L and R analog outputs. I assume it only effects XOUT.