Hi,
According to the HifiBerry documentation, the input gain can be adjusted from -12dB to +32dB in 0.5dB steps. I was able to test that in Alsamixer.
However, Alsa can increase the gain up to +40dB which I don't understand how. Hifi uses PCM1863, which has a programmable gain of -12dB to +32dB. I don't know how Hifi can increase the gain more than that.
My main question is though, how I can program the gain in Python (or C++).
Thank you
We use pyalsaaudio in our projects to access mixer controls:
http://larsimmisch.github.io/pyalsaaudio/
Thank you for the link. It still does not answer my question. There are sample codes for record and playback, but nothing on how to adjust the PGA gain.
The documentation of pyalsaaudio also includes documentation how to control mixer settings. You can find the mixer controls in the data sheet:
https://www.hifiberry.com/docs/data-sheets/datasheet-dac-adc-pro/
Thank you, I have already seen that! It is basically the only documentation HifiBerry has provided for this product.
I do not understand why HifiBerry support is always so minimal. I am on a tight deadline here and trying to find out a way to control the PGA through my application program. I can't possibly wait a day for each line of comment from Hifi support. I need a sample code or some clear instruction on how to set up PGA gain in Python or C++.
This, "amixer sset ADC 40db", is not very clear. Is it for Linux terminal? Does it work with pyalsaaudio in Python?
Looks like you're expecting something we can't deliver. Our cards use the ALSA API. This is used with basically any sound card used on Linux and there are several libraries you can use for this.
We don't provide any programming support and or support for 3rd party libraries. We also won't provide any "copy/paste" code.
If you want to program something, you really need to understand the ALSA API and it's usage. There are lots of documents available for this.
We can also offer support on programming, but this is not free. Software development is a paid service that we offer to business customers. If you want to use our software development service, let us know.
> "amixer sset ADC 40db" Is it for Linux terminal?
Yes