Comparison Check: “CD Quality” audio over the last 20 years
TL;DR: Contemporary lossless streaming services generally deliver better audio quality than physical CDs in older players. CD output quality has improved substantially over the last 20 years.
My testing of the TDK CD, Samsung DVD, and 2020 lossless streaming is now complete.
CD Transport Technology
I have experience with three generations of CD transports, and IMO they were and still are associated with playback quality differences.
The first generation (1980s) used gravity to drop the disc on a spindle, and was known for slipping and skipping. Early solutions included weighted sticker rings and heavy pads that kept the CDs from floating and fluttering. Some early players were horrible indeed, whereby inner or outer edge tracks would routinely skip. I also recall seeing magazine stories for upside-down transports (data side up), but they were rare and expensive.
[This issue seemingly also led to the infamous green Sharpie mod. I recall an audiophile vendor selling superstitious snake oil a really fancy device that would simultaneously cut the edge of a CD at an angle and apply dark green ink.]
The second generation of transports lifted the CD up after being loaded into a gravity tray. A rotary weight on the upper spindle kept the disc from fluttering – it was a cheap CD-ROM solution in the 1990s and essential for the rapid speeds desired for CD data transfers (e.g., 4x, 8x, 16x, 32x, 48x). The TDK drive used for testing has this system.
I first saw the third generation on thin profile notebook drives, with spring detents in the middle of the disc hole. Using a disc required firmly snapping it on and snapping it off. This attachment system is both compact very positive, and prevents flutter and slippage. The Samsung DVD drive uses this system.
CD Reading Technology
In the 1980s they started out with ‘sampling,’ and then due to errors went to ‘oversampling’ (2x, 4x, 8x, etc.). Early along a salesman demoing the new CD system said to me that fingerprints were “out of focus” for the laser and it was fine to hold CDs by the data side(!) Playback tech later went to single-bit, etc. Per my long gone CD players, new playback technologies did in fact change the character of CD output. I wish I had a first generation CD player for comparison, but my current possessions date from the late 1990s.
Test Music and Source Drift
I tested my old CD/DVD drives with easily accessible discs. Most are in deep storage and I should sort/condense/dispose of them. Unfortunately, many older CDs have been remastered and the original versions are not available from my current streaming sources. So, this process also ended up also comparing the impact of remastering.
Streaming sources: Amazon HD Music and Tidal
Failed Comparison (original version no longer available):
I started this with The Flaming Lips: The Soft Bulletin – The 2017 remastered version improves the top end (air) and bass definition. It adds panning and clears up congestion in some passages. One wouldn’t notice the differences without A/B testing, but the changes were too big to reach a meaningful conclusion. So, I switched to albums that hadn’t been updated (i.e., not reported as remastered, “Master,” or “Ultra HD”).
Test Albums
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Sting “…Nothing Like the Sun” (1987) – This was a 1980s marketing masterpiece, as it was proudly labeled “DDD” to indicate digital production from start to finish (vs. the lowly “AAD” or “ADD” releases that had been produced in part on analog systems). [Ironically, precipitating the return to tubes and analog gear shortly thereafter.] Because of the DDD label, I saw it as good example of what CDs were intended to be in their first generation. It was and remains a very clean recording.
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Alison Krauss + Union Station Live (2002) – Lots of clean instruments and vocals; crowd noise for added complexity.
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Johnny Cash American IV: The Man Comes Around (2002) – Simple content focused on vocals and guitar. It now comes across as quite forward and victim of the Loudness Wars.
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The White Stripes Icky Thump (2007) – It was easy to reach and has a ton of electronic distortion. Given that CDs can degrade over time, this is a pretty fresh piece of plastic.
Note: Physical CD discs do in fact vary widely in quality. Some are not quite circular, some have thin aluminum and don’t reflect light well (i.e., see through), and some have pinholes in the reflective layer that lead to pop and skips.
Test Setup
CD/DVD transport -> USB -> MacBook Pro -> DAC (FiiO Q5) Line out -> THX AAA 789 -> Focal Clear
Findings
Bottom line: The 2020 streaming sources were both plainly better than the physical CDs, and generally equal to each other (Amazon HD and Tidal). Following from mass releases and working with music vendors, they seemingly never have to deal with end-user transport and physical disc issues. Given their consistently better clarity, less noise, and stronger dynamics…I’d say they basically ‘remaster’ all CDs on the service. So, I gave them both a comparison value of 100% for all ratings.
Starting with the old TDK drive…sigh. It averaged about 90% of the streaming quality. Various issues include a lack of highs, muddy lows, inconsistencies between replays (e.g., flutter), static/confusion in complex passages and with crowd noise. It was more mid-focused and also more laid back than the streamers. All in all, the TDK was slightly but always gray and shaky. Following from above, either the transport and/or the processing technology was inferior.
Moving to the Samsung (2013) DVD player…it averaged 95% to 97% of the quality from the streaming services. The bass was more controlled and crowd noise/complexity didn’t get so rough, but the high end wasn’t as clean or black. You’d really need to A/B to spot the differences. But the differences were there and were consistent.
This is a reasonable visual analogy for the quality differences:
Follow Up
Unfortunately, I used the TDK drive long ago to rip my old (and sometimes genuinely rare) CD collection. Some discs are not available online, and the plastic is getting older and hazier every day. So, I may end up re-ripping the old discs with a newer device.