I want to input audio via toslink in, apply LP filter and get filtered audio from the toslink out.
I did not install any overlays as I don't intend to run audio through the OS.
installing the profile sine777.xml gives me a sine on the toslink out
Installing the 4way-iir.xml and inputting a sweep sine via toslink in gives me the sweep sine on toslink out. dsptoolkit set-volume 0.25 indeed lowers the volume on the signal on toslink out.
But dsptoolkit apply-settings crossover.txt has no effect. I get no "parse error" as I do if I point to non-existing file. I tried both muting every second channel and HP filtering. One example of file content I ran:
IIR_R2: hp: 2000Hz
IIR_R4: lp: 2000Hz
I use Mac and have no SigmaStudio installed
1) what is (and how can I see) the signal path from toslink in to toslink out?
2) why is there no effect from apply-settings
3) what is the clock source and if not the case: how can I set it to derive it from toslink in. My external sound card will be the master clock and feeding the dac+dsp, then my external sound card will on its toslink in get audio from the dac+dsp toslink out. To not get clicks and glitches, the output from the dac+dsp must be a slave: use a clock derived from my external sound card.
Info on my install:
I installed Rasbian lite on my headless Zero W, ran
sudo apt-get update,
sudo apt-get upgrade ,
sudo /usr/bin/tvservice -o
followed instructions to enable SPI,
sudo apt-get install -y python-dev python3-dev,
sudo apt-get install -y python-spidev python3-spidev,
sudo apt-get install git,
git clone https://github.com/Gadgetoid/py-spidev.git
sudo python setup.py install
sudo python3 setup.py install
sudo apt install python3-pip
sudo pip3 install --upgrade hifiberrydsp
bash <(curl https://raw.githubusercontent.com/hifiberry/hifiberry-dsp/master/install-dsptoolkit)
dsptoolkit install-profile https://raw.githubusercontent.com/hifiberry/hifiberry-dsp/master/sample_files/xml/sine777.xml