Engonoceras wrote: ↑Mon Jun 14, 2021 1:42 pm
I don't know about all this I'm not sure the differential EQ thing works correctly from this and other things posted. They all sound rather dull and lifeless compared to my live rips from 20+ years ago out of a first generation CD player. I would be doing these by ear if I had a good system and if I trusted my 50 year old ears.
From this I still don't think the digital pre-emph thingies or any other method are properly decoding. We are still not hearing the Toshiba correctly... correction, y'all aren't. Someone else should do a live Analog-to-Digital rip out of their oldest CD player and post so we can compare the tonality.
Therein lies the rub, as they say: it's possible that the disc was made to best be played on a Toshiba brand CD player from 1983. Finding one of those old players might be the best possible chance to correctly decode the fabled CD (the vintage player being the key that opens the corroded old lock, so to speak).
I've got a Sony CDP-190 from the late '80s right in front of me, providing a stable base for the laptop I'm typing this post on. I'm not sure that the de-emphasis/pre-emphasis EQ curve was something that was set to an agreed, calibrated, industry-wide standard that was mandatory for all CD players made back in the '80s. The RIAA curve became standardised, from what I understand, but there were variations over the years before the standard was set. We'd expect the de-emphasis/pre-emphasis EQ curve for CD players to be set to a standard but I don't think we can be 100% certain of that.
There's some interesting reading here:
https://wiki.hydrogenaud.io/index.php?t ... n_audio_CD
Some early digital recording & playback equipment, including CD players, used 14-bit converters, even though they were dealing with 16-bit audio. Some also used noisy "brick wall" filters to remove frequencies higher than the Nyquist frequency (22050 Hz). The resulting noise introduced by these converters and filters could be made relatively quiet by using pre-emphasis: boosting the signal (especially the higher frequencies) in the recording before it was put onto CD, and embedding flags in the disc's subcode to tell a CD player to apply de-emphasis on playback. Some CD players even had a de-emphasis button that could be used to manually apply de-emphasis, but now it's just a built-in feature of the analog outputs of nearly all dedicated audio CD players. By the late 1980s, pre-emphasis stopped being used because reliable 16-bit DACs with oversampling and other technologies minimized the conversion & filtering noise without the need for pre-processing the recording.
Most major-label CDs with pre-emphasis were manufactured in Japan in the early and mid-1980s. Relatively recent forum posts indicate that pre-emphasis is still used on newly manufactured CDs by some indie labels, mainly for classical titles.
A pre-emphasis flag for each track is normally stored in the subcode along with the audio data. It's also supposed to be stored in the table of contents (TOC), but many CDs have TOCs that say there's no pre-emphasis when in fact the subcode says there is. There are also some CDs which people believe were mastered with pre-emphasis, but which have no pre-emphasis flags set at all.
Maybe the Black Triangle CD was something that only found favour with some folks because it was being heard without the pre-emphasis being correctly removed (and some enjoyed the perceived extra clarity of the treble boost given when the disc wasn't de-emphasised when being played)? It's a similar thing to listening to a pre-recorded cassette, encoded with Dolby when made, through a cassette deck with the Dolby switched off.
At any rate, these uploads sound good to my ears and the spectral snapshots from Adobe Audition tell me that the tracks should sound good to most folks with a good pair of ears kept clean of earwax. Listening with a well set up system helps a lot, too.