There are a few reasons you noticed this.
1) Placebo. You "know" that Tidal is lossless and ergo it sounds clearer in the first test. But as for the others...
2) Spotify is notorious for being quiet, both on the phone and desktop, and even a faint volume boost results in it sounding "better" because you can hear more.
3) Spotify also will often bump quality down if there are any network issues. I've had times where Spotify's version was NOTICEABLY worse than Google Play's, and both of those are 320kbps (admittedly Spotify uses OGG and Google uses MP3)
You can look that up elsewhere for corroboration. Spotify has had complaints on that for a while, and I've run into it more than a few times. An album on Spotify sounded strangely muffled, then I'd pull it up on Google and it was perfect.
I'd wager #2 was the most likely factor because it's actually something that plagued me just between Spotify and Google. I couldn't avoid this feeling that Google was "clearer" when the real answer was that it was vaguely quieter. When you swap between two files and one is a hair softer, it's going to sound worse. Simple as that.
I'm not saying this with any dog in the fight. I've had EVERY streaming service at one point or another that's available in the US. Rdio, Beats, Spotify, Google, and Tidal (I'm not counting Grooveshark or "radio" services although I've used them as well). But in the end, the whole "lossless" thing is psychological. If it makes you feel good to get your music lossless versus lossy, go for it. What I really struggle to endorse, though, is people getting shilled out of their money by paying twice as much for something that's demonstrably inaudible.
I mean, let's say you get an album on BandCamp. You can get it in whatever format you want, so go nuts. Pull 'er down in FLAC or ALAC or whatever puts a smile on your face. I won't even lie, the simple knowledge that Tidal's files were lossless made listening to them more pleasant because hell, even if you can't HEAR the difference, you know that nothing is missing. That's a good thing! And if they didn't crank up the price I wouldn't argue the point (I'd use the service).
I just bristle at all of this because it leaves this sort of snooty "oh you listen to LOSSY MUSIC? Pfeh, you're not REALLY hearing it." I know you didn't say that, but it creeps in
I agree on most accounts.
1. Regarding placebo, to negate this as best as possible, I performed the blind tests, and TIDAL sounded clearer to me. Simple as that.
2. True. I have noticed this with other streaming applications as well. I have listened to some offline (not streamed tracks), and there are times when the 320kb song emits louder volume than the same song in FLAC/WAV file form. Basically these variations can most definitely fool/trick one's mind to believe that one format sounds "better" than the other.
3. This may be true, yet in my specific case, I listened via WIFI, so I did not experience any perceivable network issues when I performed the tests.
I am not debating regarding what sounds better, lossless, WAV, FLAC, 320kbps, different bitrates, as anyone's determinations about what they hear is that, what they hear. What I am stating is what sounds better to me regarding the different applications, and using their highest format available song versions, regardless of the bitrates used. If Spotify used 256kbps as their highest bitrate, and the methods they used were exemplary masters, and the TIDAL FLAC version wasn't mastered very well, and the Spotify version sounded better, then I would choose that one as the best. It's all about what application sounds the best to me. Similar to my comparisons with different iPhone music playback applications, as some sound different from each other, due to a multitude of factors.
Also, TIDAL's music is not perfect either, and would be missing something, technically, as it is using FLAC and not other higher formats such as DSD (and other DSD versions). I am one to say that I love Spotify, but ever since I tried TIDAL I preferred the music from that application more than Spotify.
As for "sort of snooty" - I don't even have an amp (yet, at least). I know that an iPhone is all that is needed for virtually every C/IEM, not a boutique DAP and/or external DAC/amp. Utilizing these to change the sound signature, and if that is what is wanted, then all the more power to those that wish to do so.
For those that can not tell the difference between file types, great. For those that can not tell the difference between IEMs that may have different technical attributes, great. Nothing regarding audio is absolutely perfect, especially regarding the total chain(s) that we all use, so the end result is that everything is lossy, no matter what.
Regarding the SE846, still loving it with the SCS, having no issues, and it's always fun to compare the SE846 to the IEMs that I listen to. The SE846 always does very well compared to most IEMs, no matter what prices the others are.
I'm interested in the Questyle QP1/QP1R regarding a DAP, as they have sounded great compared to the AK240, AK380, AK Jr, PonoPlayer, and other DAPs - it (the QP1) was able to drive the HE1000 to pretty listenable levels.