MD > CD-R: 16 or 24 bit length?

[bluecrab]

Does anyone have an opinion on whether it's better to use 16 or 24 bit output when recording from MD to CD-R? (Actually CD-RW in this case.)

My MDS-JA333ES, along with some other MD decks, has both optical output bit lengths available. I went with 16 bit, because the standalone Aiwa CD-R recorder that was the target uses 16 bit words.

Are there advantages/disadvantages to using either bit length in a given context?

FWIW, I took the resulting CD/RW and read it into iTunes using Apple Lossless. Then I burned a CD-R on the Mac from that. I am really not sure if the end result was the same, better or worse as if I'd used 24-bit output into the Aiwa CD-R.

It seemed to me like the 16 bit-to-16 bit was more an an apples-to-apples approach.

I may be doing more of this MD > CD stuff, so I'd like to get a clearer idea of what might result in the best sound.

Thanks and happy holidays!

[sfbp]

Hmmm... didn't we in a sort of roundabout way determine that in fact the max is really 20 bits? Because S/PDIF is a 20-bit format... For some reason I had it in my head that the options were 20 and 24 bits. Intriguingly according to manuals only the 920 (not the 930) and 555 actually have 16,20 and 24.

Having never had one of these bit-length-switching decks, I have nothing to go on.

I have noticed that playing back ATRAC from a PC it is best to use a component that transmits 44.1kHz S/PDIF rather than 48kHz (std for Video), as there seems to be noticeable "mushiness" in the latter case.

My guess then would be that 20 is the best setting (tant pis).....

[bluecrab]

Well, thanks, sfbp...I think.

The MDS-JA333ES does have the two settings and only two: 16 or 24, with 24 being the factory default.

I did find this, which is enough to make my head spin:

http://www.head-fi.org/t/415361/24bit-vs-16bit-the-myth-exploded

Anyway, I guess the thing to do, as it doesn't seem to hurt anything, is to just leave the setting alone @ 24 - although it does make me wonder why, then, would Sony even bother adding this "feature" to the 333 and other decks.

IWBN if Sony, in their inifinite wisdom, would have mentioned in the documentation when one might want to use 16 and when 24. But tant pis, as you say, or fn Sony, as I say, they do not.

FTR, I have gotten pretty good results, before I even thought much about this topic, by using the default 24-bit setting when doing MD > MD copying.

[sfbp]

I think somehow that the default for all Sony decks is to output 20 bits which is the specification of S/PDIF and Toslink. The esoteric discussion in that reference is mainly about internal signal paths BEFORE they are sent from one device to another, methinks. Mind you he doesn't actually talk about optical or coax transmission.

I didn't read the whole thing but I see it goes for 64 pages!!!!! As my SO says, "maybe later..."

The bit about dithering by adding noise makes perfect sense - it explains why ATRAC can make a perfectly good recording at 66kbps. They manage to throw away all those bits of noise when compressing. When you look at frequency response of output, most of the time what you are looking at is the noise curve... which is why it looks (almost) the same always. I think ATRAC is (internally) 24-bits always.

I know that for recording, 24 bits works nicely. Mainly because when you have to amplify digitally (= blow up the sound) for something too quiet, there is enough resolution left to make a decent sound even after turning up the (digital) gain. Just like the man says.

An interesting question would be - if you output on the "16-bit" setting, will the sound still get "dithered"? Perhaps it's a question of whether the dithering happens before or after some other step.

[MDietrich]

May I chime in?

If you record from 24/20 Bit MD to CD-R it is crucial to change the bit-depth of the digital output to 16 Bit. If I remember correctly the MDS-JA 333 ES then decreases bit-depth with dithering. If it wouldn´t do that the CD-R recorder would get the full 20/24 bit signal and simply ignore those additional bits which could theoretically create truncation artifacts. The CD can ONLY ever use 16 bits, nothing more, nothing less. But with proper dithering (done by the MDS-JA 333 ES) you can avoid artifacts AND capture almost all of the full resolution on CD.

Think of it as a built-in Super Bit Mapping that can be switched on or off for your convenience. For recording on CD I´d switch it on. But if you output the MD signal to a DAC capable of 24 Bits switch it off.

[sfbp]

A program like Sound Forge will dither as it does bit conversion. I know it does, and it asked me about what kind of dithering I wanted. So if one burns a CD from a 24-bit WAV then that's exactly what happens (during the process).

I'm surprised that the CD-R machine doesn't have dither circuitry in it. But then again, I've never seen the need for one after discovering that PC's are the best (and only?) way to produce CD's. There was a whole nonsense about buying "Audio CDRs" and I wonder if that is indirectly related to this challenge. They still sell them, too - I had always the impression that someone decided they could sell snake oil with that product.

Going out on a limb here... did the manufacturers of the CD-R recording machines include the dither (or some other) circuitry ONLY when their drive firmware recognised an "Audio" CDR?

[bluecrab]

MDietrich: That is exactly why I was asking to begin with. It also could help explain why I usually get excellent results recording between MD decks @24-bit setting.

sfbp: MOST of the standalones are able to use only Audio CD-Rs - you cannot even record to a regular CD-R on them. My HHB BurnIt is an exception, but even the HHB (which famously strips SCMS - remember that? - and outputs SCMS-free) likes lower-speed discs, say, up to 12x, better than the 52x ones for recording.

Now, I have have a nice rack full of gear that includes an Aiwa CD-R, and it's quite a simple matter for me to switch inputs to the Aiwa and record from any of an MXD-D400, MDS-JA333ES, CDP-XA20ES or, if I like, I can use the Aiwa much like I use the MXD-D400, except both its sides are CD. It's also no big deal for me to swap a few front-panel connections and record from any particular source onto any particular recordable target. That old Aiwa (c. 1999?) has outlived more than a few computers!

There was indeed, IIRC, some just-give-us-the-money reason for the creation of the so-called Audio or Music CD-R, but I forget what it was. I have such gear as I have and need to use appropriate media.

I certainly use my Macs to burn CDs, as well, but my answer to your question about PCs (I assume this includes Mac) being the "only?" way to produce CDs would be a definite "no." It's kind of funny you should mention it, though. Just the other day I was burning a CD on the Mac and some other concurrent operation caused the burning to just stop. The player part kept trying to write, but the burning s/w (iTunes) was having none of it. Have had the same thing happen on PCs and UNIX/Linux boxes, too. It's not a regular occurrence, but it sure is annoying when it does happen!

[MDietrich]

MDietrich: That is exactly why I was asking to begin with. It also could help explain why I usually get excellent results recording between MD decks @24-bit setting.

Yes, true. Starting with ATRAC 3.5 MD used 20 Bits, starting with ATRAC 4.5 it used 24 Bits (how much bits are actually given out I don´t know). BTW, the inputs of your decks is independent from what you configure in their respective menues as they will always accept the highest bit-depth possible on their digital inputs: 24 Bits (except 3.5 & 4.0: 20 Bits... but with that bit-depth truncation doesn´t matter anymore).

sfbp: MOST of the standalones are able to use only Audio CD-Rs - you cannot even record to a regular CD-R on them. My HHB BurnIt is an exception, but even the HHB (which famously strips SCMS - remember that? - and outputs SCMS-free) likes lower-speed discs, say, up to 12x, better than the 52x ones for recording.

(...)

I certainly use my Macs to burn CDs, as well, but my answer to your question about PCs (I assume this includes Mac) being the "only?" way to produce CDs would be a definite "no." It's kind of funny you should mention it, though. Just the other day I was burning a CD on the Mac and some other concurrent operation caused the burning to just stop. The player part kept trying to write, but the burning s/w (iTunes) was having none of it. Have had the same thing happen on PCs and UNIX/Linux boxes, too. It's not a regular occurrence, but it sure is annoying when it does happen!

CD-Rs and Audio CD-Rs technically are exactly the same. The latter one only has an additional embedded code (in the ATIP area I believe) so that any purely audio-compliant recorder will recognize it, subsequently allowing you to use it. The 'normal' CD-R for PC only lacks this code. The only difference between CD-Rs and Audio CD-Rs is that royalties have been payed for Audio CD-Rs, royalties for expected audio use - that´s why audio CD-R recorders won´t allow you to record on 'normal' CD-Rs since no one payed royalties for them. In some rare cases however there existed (still exist?) Audio CD-Rs specifically constructed for lower write speeds. With basically all available high-speed CD-R it´s difficult to write at low speeds because the error count will be higher as they are constructed for high writing speeds (16x and above), using that they produce very few errors. I´ve tried this myself with four different drives and from my error counts I found this to be true. Slow burning speed (1x, 2x, 4x, 8x) was beneficial for quality 10 years ago - but it isn´t anymore. Sorry for veering off-topic but I had to explain why special Audio CD-Rs might still be suitable: they might be engineered for lower writing speeds necessary for older CD-R HiFi recorders.

[netmduser]

I have audio flac at 24 bits. To burn these to cd I had to convert to 16 bit wav. I chose not to use dither. Was reading about dithering and it can produce tape hiss however by not dithering I have simply created a 16 bit cd truncated.

To compare to 24 bit audio, if I convert these to 24 bit wav and burn to a dvd, use dvd to play and then record to md using optical input from the dvd player what will happen? Does the MD optical input convert 24 bit to 16 bit?

[MDietrich]

I have audio flac at 24 bits. To burn these to cd I had to convert to 16 bit wav. I chose not to use dither. Was reading about dithering and it can produce tape hiss however by not dithering I have simply created a 16 bit cd truncated.

The result depends on the music. Punk, Rock or Pop have very weak dynamic capabilities (differences between soft and loud are very small) whereas classical or jazz have more or less level differences up to 50 dB. The latter cases might reveal truncation artifacts (quantization noise) on soft parts while the former for certain won´t. However, if I´d do something like you I´d use dither ALWAYS. Dither is harmless noise, it shares many characteristics with tape noise (or shaped white noise) but its gain is much, much lower and I´ve never ever witnessed it becoming audible. You can safely use it all the time. But only once on your last processing step and you shouldn´t do any processing afterwards (e.g. resampling; not even volume correction), dither should always be the last step.

To compare to 24 bit audio, if I convert these to 24 bit wav and burn to a dvd, use dvd to play and then record to md using optical input from the dvd player what will happen? Does the MD optical input convert 24 bit to 16 bit?

No. Since ATRAC 3.5 the MD accepts 20/24 Bits through its S/PDIF input; all my MD recorders (in my signature) accept a full 24 Bit signal and encode it properly. But you won´t gain a benefit if you upconvert from 16 to 24 Bits. If you´d do that you´d only add zeros in the 16to24 bit space which add nothing, they are not even interpolated. Before you play original 24 bits material you should also make sure that your DVD player transmits it without changing it to 16 bits. Some DVD players do this because of (stupid) copyright issues, on many it´s configurable, on some it´s not.