I have a 22 kHz mono audio recording, which is mainly speech, a reading. I would like to upsample somehow to 44 kHz, to improve the audible quality. I have read about there are AI methods for upsampling pictures, even videos to a higher resolution. Maybe there is some similar methods for audio too.
The recording comes from radio broadcast, so the recording was excellent studio quality, streamed in 128 kbps, 44 kHz, stereo, but somebody, who did the recording, downsampled it from the original 44 kHz broadcast to 22 kHz, mono. Hence the sound quality is far from optimal, sounds like an old telephone, I think, due to the missing high frequencies.