It says on my Spotify that the "Extreme" quality of streaming is equivalent to 320 kbit/s. Is that standard hi def audio quality? And is it the same "Extreme" quality when you download it and make it available offline? It does not say in the Download settings. Also, is there a software that will allow you to save them on your hdd/storage?
Yes, extreme streaming and download files are both 320kbit, or around 8MB a track. This is not yet the definition of Hi-Res Audio, as that is mostly taken as higher than CD quality. The 24/192 albums I bought in HDtracks are around 5Mbps, and a single track is around 300MB. For downloading, there should be a "switch" in the playlist/album to download so you don't need to stream it all the time.
That is standard resolution. Spotify uses OGG and MP3. The latter limits them to a max of a lossy 16/48.
The boundary between standard resolution and high resolution audio is blurred, however. There is a lossy format with similar bitrate that claims to be high resolution; that is MQA (master quality authenticated). Tidal uses this format.
http://www.mqa.co.uk/
Tidal by default is mostly lossless CD quality; Tidal masters (MQA) is only for home use for now, you either need the windows/mac application or an MQA certified network streamer.
have compared aptx with non aptx mobile phone streaming wifi to a hifi system and the improvement is significant... It has gotten me curious how aptx hd would sound. Lg g5 and g6 already has the inboard chip but no available bt receiver dac yet. Arcam or astrel and kern would pilot this, i hope
Have you heard Sony's LDAC? I find it way way better than Aptx, unfortunately, nobody owns Sony phones and walkmen!