Audio Quality: 320kHz vs 48k 16bit vs ?

I’m sorry if this has been covered elsewhere. I’d love being redirected to the relevant pages. As it stands, I’m just starting to play around with my HiFi set up and so am a bit ignorant.

While I understand sampling rate (eg 48k) and depth (16 vs. 24), I don’t understand how this corresponds to the ‘320kHz’ number that Spotify supposedly streams at.

Is it similar to the way my BOSS DAC has, according to their spec sheets, “Sampling Frequency ranges from 8 kHz to 384kHz ?”

What about the fact that my HiFiBerry Digi+ can apprently feed a digital stream to my HK amp with a built in DAC at 192kHz?

Could someone enlighten me?

Thanks!

Actually what you can change on Spotify directly is not the sample rate as such but the bitrate. So it’s not 320kHz but 320kbit/s. The bitrate just describes the amount of bits processed in one second. How high the bitrate is relies though on the used format, the bit depth and the sample rate. While for loseless formats the bitrate is rather uncommon to be used as reference, it’s used as reference for lossy formats like mp3. Actually Spotify “Extreme Quality”, meaning 320kbit/s, is comparable with a 320kbit/s mp3 file (I think they actually use ogg or something like that). Though if you rip a regular CD to FLAC, for example, the audio file will have 16 bit depth, 44.1kHz and a bitrate of something around 700-900kbit/s.

While there are no specifications on what sample rates Spotify actually uses I wouldn’t expect it to be higher than 48kHz or even 44.1kHz as they anyway stream in a lossy format so your DAC is more than sufficient to handle that input.

Ahh. That’s starting to make sense. 48k samples/s * 16 bit = 768bits/sec.

Spotify is 320kb/s, but is compressed using Ogg, so if the compression is ~2:1, then we’re getting close to the 768b/sec but with some loss.

To answer my own question about the 192k output, I’m guessing that’s for 8 channels of surround sound at 48k/s.

Clarity gained, both conceptually and audiophilicly. Thanks much!