Here is my main playlist, it isn’t flac, but on my sorta not terrible setup they sound really good, and may not be all that bad: (3) [Muzic:Main] - YouTube
Are most of these sound files that bad? They are uploaded from youtube themselves using whatever actual files the artists give them… I think.
From What Hi-fi 2019
"YouTube Music has certainly upped its game for audio quality since we last tuned in. The service launched with 128 kbps streams but has now doubled the bit-rate to 256 kbps (the format is AAC). Unsurprisingly, the listening experience is greatly improved, but it’s still not quite banging.
Spotify and Apple Music both sound noticeably better. Listening to Heart Shaped Box by Nirvana, YouTube Music is missing a level of detail. The grinding guitar solo doesn’t scrape through your nerve endings with the same harmonic detail as is does elsewhere - it’s or homogenised with other tones. "
If you have good audio gear (speakers, headphones etc).
You should notice the difference between the audio quality. It’s barely listenable imo for the good songs and when going for the “goosebump” chills. You need better quality.
But in a car? Sure why not but could as well Spotify for the touch better audio.
Some YT songs may have been “boosted” or tweaked in many ways, making them nothing like what it should be but some still like Youtube for the videos and easy to use features.
These findings are very interesting. I just downloaded the app to windows, time to see how this goes!
Edit; trying it out now, there is ABSOLUTELY an improvement, I don’t believe I’m at the highest quality yet.
Edit 2; changed quality from normal to high, time to see the difference. Edit 2.5; tried it and not a massive difference, don’t have good enough equipment yet to hear it at least, motherboard dac and powered speakers from 2014 lol.
Edit 3; This my playlist with the highest quality YT stuff I’ve got, if you wanna try it out; YouTube Music
This is an especially good one; YouTube Music
The plan isn’t to stream music, the plan is to use youtube to find music, then download flac versions from other sources TBD, and play the music from hardware to guarantee the quality of the music and that it will never suddenly disappear from a “god damn streaming service”. I’ll play these from my PC drive using foobar/a DAP.
Most new music might be uploaded by them if they’re now explicitly managing this for use in YTM, but for every older album where you can see different thumbnails on some of the videos you can bet they cut costs and went with whatever version was already up. But this is for the public-video version, if they have premium stuff they better damn well serve provably higher quality than some 10yo upload.
Then again back in the days of Google Play Music all they were offering was 320kbps MP3 with negligent encoding that allowed clipped peaks, and I somehow doubt they’re about to go through their massive collection and replace everything with better sources just because they’re now asking for money under the YTM name and forbidding us from downloading DRM-free files. So in general I wouldn’t expect anything better than 320-MP3 from them at any subscription tier.
LOL, so they’re selling their 320kbps database as 256kbps, maybe they’ll come out with something “even better” later and give us what we already had with GPM. 
Anyway, the funny thing about all this is how their top-tier encoding for the public-video form of the songs is actually in 160kbps-limited VBR Opus, which allows some pretty damn amazing quality if you upload a lossless/uncompromised original, if I judge by this gem I recently found: https://www.youtube.com/watch?v=63TNghYjK1U
Download the Opus audio with
youtube-dl -x https://www.youtube.com/watch?v=63TNghYjK1U
and check out the spectrogram in Audacity: not a single sign of lowpass filtering anywhere below 20 kHz. That is something you just do not find on YouTube normally.
So I took a look specifically at a “topic” song that was recently released (December 2020) and shows as a video with no comments section on the public YouTube and with “Provided to YouTube by Warner Records” in the description, so in theory they should have received a lossless version of the master to recode to whatever they want to use in different contexts. This would be Lianne La Havas - Bittersweet.
I check out the audio formats and notice that strangely the M4A/AAC appears as the “best” (presumably because it came out at an average bitrate of 129k?), whereas the Opus version is just sitting there (with its average bitrate at 127k). So if you’re on a device with no bandwidth problems and your browser supports M4A, you will probably be served the “best” variant, with a spectrogram that looks like this (hard cut at 16 kHz):
Whereas the better audio in the more advanced encoding is… just there for when you’re using a browser that supports Opus but not M4A/AAC? Which is, what, no browser anywhere? 
And its spectrogram looks like this (hard cut at 20 kHz, only small signs of filtering around 16k):
It’s the free version, so we can’t really complain, but… kinda stupid to have the better audio just sit there because it’s not classified as “best”.
LE:
Nope, both Vivaldi and Firefox play the Opus audio at any resolution I select, so YouTube does know where its best audio is. Maybe this “best” thing is a concept that belongs to the youtube-dl tool I’m using to check out the formats, and not to YouTube itself.
I remember hearing a difference on my 4th gen iPod Nano with Apple earbuds between 128, 256 and 320kbps MP3s.
