I’m trying to export some audio records as a WAV files with the following properties: 8000Hz, 8-bit Mono, 64 kb/s.
I use “Unsighned 8-bit PCM” as an export option.
In Audacity all records sound clear and fine.
The problem is that all exported files are noisy (expecially on silent sections of the audio).
How can I fix that?
I’m on Windows 10 64-bit.
Audacity version is 3.0.2.
When an analog signal is digitized you get [u]quantization noise[/u] (the result of “quantization error”.). It’s inaudible at 16-bits but at 8-bits you can hear it. It “lives in the background” like regular-old analog noise so it’s most noticeable with quiet sounds. However, unlike analog noise it goes-away with “true digital silence”.
Dither is intentionally-added noise that’s supposed to be preferable to quantization noise.
That’s correct. 8-bit audio is inherently more noisy than 16-bit, which is why 8-bit is never used when high quality audio is required.
Also worth noting that 8000Hz sample rate audio has an upper frequency limit of 4000 Hz, so speech and music will always sound a bit muffled.
(CD quality uses a sample rate of 44100 Hz, which is Audacity’s default and has an upper frequency limit of 22050 Hz (slightly less in the real world), which is sufficient for crystal clear speech and music recordings.