Despite the regularly proclaimed death of physical media, new audio albums are still being published on CD and vinyl. There’s something particularly interesting about Lorde’s new album Virgin however — the CD is a completely clear disc. Unfortunately there have been many reports of folks struggling to get the unique disc to actually play, and some sharp-eyed commentators have noted that the CD doesn’t claim to be Red Book compliant by the absence of the Compact CD logo.
To see what CD players see, [Adrian] of Adrian’s Digital Basement got out some tools and multiple CD players to dig into the issue. These players range from a 2003 Samsung, a 1987 NEC, and a cheap portable Coby player. But as all audio CDs are supposed to adhere to the Red Book standard, a 2025 CD should play just as happily on a 1980s CD player as vice versa.
The first step in testing was to identify the laser pickup (RF) signal test point on the PCB of each respective player. With this hooked up to a capable oscilloscope, you can begin to see the eye pattern forming. In addition to being useful with tuning the CD player, it’s also an indication of the signal quality that the rest of the CD player has to work with. Incidentally, this is also a factor when it comes to CD-R compatibility.
While the NEC player was happy with regular and CD-R discs, its laser pickup failed to get any solid signal off the clear Lorde disc. With the much newer Samsung player (see top image), the clear CD does play, but as the oscilloscope shot shows, it only barely gets a usable signal from the pickup. Likewise, the very generic Coby player also plays the audio CD, which indicates that any somewhat modern CD player with its generally much stronger laser and automatic gain control ought to be able to play it.
That said, it seems that very little of the laser’s light actually makes it back to the pickup’s sensor, which means that along with the gain the laser output gets probably cranked up to 11, and with that its remaining lifespan will be significantly shortened. Ergo it’s probably best to just burn that CD-R copy of the album and listen to that instead.
Somebody want to explain this comment:
“That said, it seems that very little of the laser’s light actually makes it back to the pickup’s sensor, which means that the gain gets probably cranked up to 11, and with that its remaining lifespan will be significantly shortened. ”
Amplification of the signal shouldn’t reduce sensor lifespan.
I think part of the gain circuit is the power to the laser led.
Even then, it would be weird for manufacturer to set the maximum power high enough to actually significantly shorten the laser lifespan.
Every company on Earth would absolutely let you break your own device if they can sell you the replacement.
I wonder what would happen if he spray-painted the top of the CD with silver (or even white) paint.
Granted, that’s not the same as an embedded reflective layer but… I wonder if it would improve the pickup signal at all.
When I heard about Lorde’s clear CD, my first reaction was that Weird Al needs to release a new LP on Vinyl… but one with no grooves on it because…. you know… something-something-art.
There are or were plenty of multi-disc vinyl releases where one side of one platter was an artistic, unplayable design. I have one, I think it’s Parliament Funkadelic, where the album came with a standard 45 and also a smaller single, and the single was really a single with one song on one side and the back side of the disc looks something like microcrystalline quartz or druzy quartz. I’ve seen others where there’s a single spiral that shoves the tone arm off the outside of the record.
A spiral that sends the tone arm off the record is a terrible idea. If the turntable is larger than the record, it could rip apart the stylus.
If the top is still lacquered, it could make matters worse since you’ll have a strong reflection unrelated to the track.
I second that! A square vinyl by the way.
I’d expect nothing less than him exploring the possibilities of a dodecahedron shaped vinyl LP.
So we go from three-sided (err, triple-grooved), cf https://en.wikipedia.org/wiki/Multisided_record … to none.
Spın̈al Tap would approve.
The signal is rectified and goes into the DAC. Thr big issue is whether the rectifier is triggered to give us a consistent digital signal. There must be a nominal and minimal threshold of the laser signals amplitude for the rectifier to engage and output a bit. Newer cd players may be able to read more faint cd pressings. It seems like these would be more sensitive to dirt or scratches?
Afaik Adrians style is going in blind and figuring things out on the fly thus he didnt study how reading CDs works and makes a lot of bad assumptions :(
– what wobble is and where it comes from
– what is and is not a bad/ugly signal
– what is an Eye Diagram and how to trigger one properly
no you cant :)
maybe better one is a reply to Adrian from TheRetroChannel https://www.youtube.com/watch?v=rq323smuXjo
The player that didn’t work didn’t even try. It probably has a rudimentary light-based disc presence detector. I suspect if you could “trick” the disc detector, it would probably play fine. Although the signal is weak, the SNR should still be high, and since the signal is ultimately converted to digital, it should be fine.