I've found this topic: https://bluecherry.zendesk.com/entries/20208298-How-to-get-16khz-g723-audio-from-bluecherry-card-
Have the driver support for 16 kHz now? I really need it. Sound captured with 8 kHz is terrible.
I've already found datasheets, and even tried to re-hardcode sample rate to 16000. But it turned out that it's quite difficult for me.:-)
please describe what kind of audio input device do you plug into your Solo card. What Solo card do you have, 6010 or 6110?
I'm using tiny microphones. I know, that they can give better quality, because I've captured sound with them using another card.
I have solo-6110.
I'm sorry to bring bad news, but the codec used by the card (G.723) is limited to 8KHz by design, it can't operate at other sample rates. While you can theoretically force the card to operate outside the standard, the results would be of even lower quality, probably you will get lots of noise and low pitched sounds muted.
I thought, that by 16kHz-G.723 they mean G.726, which is compatible with 8kHz-G.723 and supports higher sample rates. May be you should try this decoder for 16kHz?