Hi. I started a discussion on the thread ANNOUNCE: piCorePlayer 5.0.0 (starts on page #518) and it was suggested to start a new thread (thanks to @Man in a Van and @paul- for their help so far). To summarize
As I understand it, the ESS9038Q2M DAC chip (as found on the Khadas board) can control the volume of its outputs (instructed by i2c). I understand that this is potentially an optimal method of controlling volume is because it does it by using some serious hardware oversampling (or something like that) which is preferable to altering the stream in software before it is sent to the DAC (where it is usually advised to leave volume setting in players at 100% for bit-perfect transmission). Of course, chip-level volume control also offers us the opportunity us to remove pots / stepped attenuators from the signal path (if we dare to place trust in our settings!)
Now, I am certainly able to control volume coming out of the Khadas board (which attached to a Pi 3B via USB) using the slider on the LMS interface but I would like to understand what PCP is doing. Is PCP:
A - doing software adjustment of the stream sent to the DAC (i.e. not bit perfect)
or
B - sending the original bit perfect stream and instructing the DAC (via the driver) to alter its outputs (i.e. the supposedly preferable method).
If it is not doing B, can it be done? I would be very grateful for any advice.
Some relevant info
Many thanks for listening!
As I understand it, the ESS9038Q2M DAC chip (as found on the Khadas board) can control the volume of its outputs (instructed by i2c). I understand that this is potentially an optimal method of controlling volume is because it does it by using some serious hardware oversampling (or something like that) which is preferable to altering the stream in software before it is sent to the DAC (where it is usually advised to leave volume setting in players at 100% for bit-perfect transmission). Of course, chip-level volume control also offers us the opportunity us to remove pots / stepped attenuators from the signal path (if we dare to place trust in our settings!)
Now, I am certainly able to control volume coming out of the Khadas board (which attached to a Pi 3B via USB) using the slider on the LMS interface but I would like to understand what PCP is doing. Is PCP:
A - doing software adjustment of the stream sent to the DAC (i.e. not bit perfect)
or
B - sending the original bit perfect stream and instructing the DAC (via the driver) to alter its outputs (i.e. the supposedly preferable method).
If it is not doing B, can it be done? I would be very grateful for any advice.
Some relevant info
- From my reading of this thread on the Khadas forum, DAC controlled volume has been achieved using Volumio (but much of it is over my head so Im not sure!)
- This widget is available which enables DAC controlled volume (via i2c) it is shown attached to the Khadas Tone Board here on Audio Science Review.
Many thanks for listening!
