Comment by mmastrac | Hacker News Reader

Comment by mmastrac | Hacker News Reader

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> I can also write how CD tracking quality affects audio clarity, but this comment is long enough. In short, Yamaha's old CD-Recorder, CRW-F1 really improved sound quality by abusing Red Book standard by lengthening the pits of audio CDs. It reduced to capacity to 68 minutes, but it was worth it, esp. on lower end CD players.

Sorry this one part especially makes no sense. Digital is digital. Either it added more samples per second, or more bits per sample, or it's snake oil. There's a stream of bits that comes out of the reader. There's no residual information about the length of the pits.

EDIT, yeah sorry this is completely and utterly impossible that you are getting better "audio clarity":

"Yamaha tries to attract computer enabled audiophiles with the Audio Master technology. Audio Master promises reduced jitter and decreased error rates for audio recordings via extended pit and gap sizes on the CD-R. This is actually quite simply achieved by increasing the disc rotation speed vs. the laser clock frequency. In other words, Audio Master recording at 8x rotates the disc at 8.2x, thus creating the extended pit & gap lengths. This naturally reduces the capacity of the disc."

Literally they are just spinning the disc faster, reducing capacity and make it slightly less likely that errors will be read. If you're getting read errors on playback, that means your disc is dirty or your CD player sucks. It's the same bitstream, just read at a different linear rate.

If you honestly believe that this is an audiophile concern, I'd urge you to reevaluate a lot of your other beliefs, because they are clearly not all grounded in technical facts.

The problem is not the values delivered to the DAC. It's the aperture error of when the DAC was clocked. This affects what those sample values actually represent. If the clock is being extracted from the pattern of pits and there's a way to reduce the jitter, you will get a more accurate signal.

However, I'd hope that anyone that cares about fidelity has a CD player that does a little more to generate a DAC clock. NCO run by a software PLL or a hardware PLL with a good loop filter are things I've heard of, but control systems is not my specialty.

CRW-F1 didn't encode more information into the pits. It allowed lower end DACs to have more time to switch properly by giving them a slower signal stream within acceptable limits.

DAC's digital part is easy. What differs in quality is the analog part. If DACs were that simple, a 25 cent DAC would power every unit from bottom bin to top tier.

Before that Yamaha CD player I had, I used a lower end Sony CD-Player (I don't remember the model, sorry). Writing the same album, to same brand of CD-R, with the same speed in two different modes created two audibly different disks.

I sometimes challenged myself by writing in both modes, not marking the CD-Rs, and the audio difference was always audible. Even after weeks. 68 minute CDs were always had larger sound stages with more clarity and instrument separation. This is again on the same AKAI AM-2850 amplifier.

I guess this difference would be impossible to hear today, because higher end units have better tracking and better DACs. Also some of them use DAE and use multi-second buffers, so the "slower stream" is no longer present in the pipeline due to buffering.

A CD signal stream fed to a DAC is a 44.1 kHz 16-bit signal, period. All you did was force the drive to spin a bit faster to keep tracking, or let it fill its buffers more slowly if it spun at the same speed. The buffers, after error recovery, are what feed the DAC. Assuming an error-free read on two discs burned with the same data (regardless of "pit length", disc material, etc), you get the same bits in the buffers.

There's no "slower bitstream" for the DAC. That's provably nonsense and you can work it out from basic principals. The same bits would come out of the optical interface of a CD player, at the same rate either way. If the CD player has a built-in DAC, the same bits would get fed to that same DAC either way.

I'm sorry, but if this is truly what you believe, it really puts everything else that you said into question.

To give you the benefit of the doubt, I might say that the lenses or lasers on your CD players are filthy, and you're just hearing skips or noise from poor reads and that a slower-written, borderline-spec disk might just allow them the function better. Perhaps your player was interpolating or concealing frames [1] that it couldn't read correctly and failed to correct via ECC and you were just hearing a poorly reconstructed digital data stream.

This sort of confident incorrectness, ignoring the underlying technical architecture, is probably why people don't believe anything that an audiophile says.

[1] https://www.pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_...

I don't know much about the Yamaha technology referenced, but he's not totally off his rocker.

CDs don't record 0s as pits and 1s as lands. A change from pit to land or land to pit is a one, and no change over a time base is a 0.

Therefore, the recording and tracking performance can be affected by the disc content and processing applied.

Sure, I can understand how slightly changing the layout of the pits and lands can potentially reduce the error rate. But if I'm already getting playback with 0 C2 errors, there is absolutely no change in quality from the original signal.

Advanced Audio Master visibly reduces C1 errors in recorded media, to almost negligible levels. While C1 error can be corrected without any degradation theoretically, its result is up to the CD player's capabilities (and quality).

CDRInfo's tests back in the day showed dramatic improvements in C1 levels, see [0]. Considering some of the lower end CD players by leading manufacturers didn't even had 16bit audio decoding and used late stage oversampling, reducing C1 errors was/is a big deal in recorded media.

As I said in my earlier comment, this mode lead to clearly audible improvements in my older, low-end Sony CD player. I don't how how will it fare in my new Yamaha player due to technology improvements.

[0]: https://www.cdrinfo.com/d7/content/yamaha-crw-f1e-cd-rw?page...

Sure, the C1 rates are lower here for one kind of media in one actual comparison, but C1 errors below a certain rate are entirely correctable errors. Meaning, you're not going to lose data when it gets reconstructed. You are not losing fidelity of the CD by having a lower C1 rate in the 20s to 40s; every bit decoded is being played back exactly as originally encoded. Otherwise reading data off a CD would always have significant amounts of corruption every time you installed software. Every time you opened a photo off a photo CD you'd get all kinds of JPEG corruption.

Assuming you have a properly functioning CD player, these errors have zero input in the quality of a CD being played. If you have a noticeable difference in audio quality between a CD with a max error rate of 24 or 32 C1 errors, you've got a tremendously faulty CD player that is complete trash.

Its funny too because in this table it shows the Mitsubishi media performed about identical or better in every speed while being significantly faster at recording. The 1x speed with AudioMaster on for Plasmon is the worst result, ignoring the time they burned 16x media at 44x speed. This table is also challenging to actually compare, because they show different speeds for the different modes (1,4,8x for AM, 4,16,44x for regular) so the only one we can really compare fairly is the 4x. Even then, at 16x speed AM off it had a lower average error rate than 8x speed with it on!

Don't get me wrong, burning a lower error rate from the get go is good, it implies the burn will possibly be more reliable over time as you get things like scratches and other imperfections on the disc. But arguing that a disc with an average of 2.1 C1s vs 1.1 is going to be noticeably different in the sound is absurd. And once again, even then this showed an improvement only in one of the two medias tested. Maybe its better in more media, maybe its worse, maybe there was just something odd with their burns and this is largely just noise in the overall results of burn results from this drive.

I'm still not convinced AM actually did anything but reduce your recording time. Your link doesn't say anything of actually increasing the audio fidelity in the slightest, just that in one straight comparison the C1 errors were lower. Practically every result in that table other than the 16x media being written at 44x speeds is already massively in the "negligible levels." Being below 220 is "negligible", and all of these burns (aside from the one using AM at 1x speed!) are well below that.

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