CoiL
Member of the Trade: Wood Audio Accessories & Modifications
In the morning, with still sleepy brain/ears:
Will try to to long test tomorrow maybe.
Will try to to long test tomorrow maybe.
Did you expect them to make it an easy test to reproduce?
In the morning, with still sleepy brain/ears:
Will try to to long test tomorrow maybe.
When I saw the Tidal listening test, I was really annoyed by the poor reporting of results (i.e. the lack of stats).
I went and built an 'alternative' test which uses an ABX-style format to test *exactly the same samples*.
No null because of the sync issue, but plot spectrum shows a slight increase in bass and treble in the lossless version of the Killers song. The difference in bass is about 1 dB at 60 Hz and goes up to 3 dB at 20 Hz, likewise the treble difference is about 1 dB from 10-16 kHz. I don't know if this is the result of the codec itself, or some EQ on Tidal's part. Hopefully someone with better testing software will find something more concrete.
So, do I understand correctly that this test is intentionally "produced" for PR purposes so that ppl could detect differences more easily?
Indeed, I have noticed similar treble and bass boosts on blake_30.flac vs. blake_30_lossy.flac. It looks more like EQ (although the curve may not be the same for all files) than encoding artifacts to me. The difference is enough to be relatively easily detected in an ABX test.
Edit: this is the frequency response I have extracted from blake_30_lossy.flac (relative to blake_30.flac), it matches the description of "Compressed music weakens for instance the pressure in the bass, details in cymbals and gives the sound less headroom.", and looks like parametric shelving EQ, so it could very well be intentional:
(click to view full size version)
I transcoded their lossy files using dBpoweramp using Lame mp3 192kbps CBR, and I fail to tell the difference by ABX, no better than guessing.
It is probably best to simply download the files, and use the foobar ABX plugin, or similar software. Here are the download links:
...
I suspect that differences were intentional created, as I have never been able to successfully ABX between lossless and AAC 256 or Lame vbr -0, much less lossless and AAC 320.