Maluvia wrote: Thanks for these very interesting links. It's clear. Files copied from the firewire hard drive sounds warmer. It's because of the fire in the wire. But you're adviced to backup your sessions anyway, cause the quality loss is "very very very slight". :-) // c. -- www.cesaremarilungo.com

On 27 Feb 2006, at 18:11, Maluvia wrote: There are two separate issues here, one being a suitable word length for recording, the other being a suitable word length for distribution. For distribution, I would contend that 16 bits is fine (and in fact that the vast majority of CDs don't come close to using that). After all by this point in the process we know what the peak value is..... For recording (where you want 20db of headroom above nominal level to avoid clipping that once in a lifetime take, and where you don't really know what the actual peak levels will be, then sure go to 18 or 20 or 24 bit (and accept that the low bits will be essentially random). This is not because you are likely to have >96db dynamic range for most instruments but because you don't know ahead of time where that range starts and stops. I don't buy it, sure I buy jitter being a issue at the DAC, but that is ONLY an issue with conversion to or from analogue, it cannot be an issue with the storage or with digital transfer between storage devices where either the data recovery is OK is it is not. If the MD5 hashes match the data is probably identical..... If the diff returns nothing then the files are identical, at least as far as the computer is concerned (or diff has a bug). Sure hard disks have a specified bit error rate, but it is fairly close to zero, as the fact that these things work at all can attest. Seems to me to be saying that as long as you actually manage to make an exact copy of the file, the only issue is jitter going to the DAC? Checking you have an exact copy is easy, in fact FLAC can store an MD5 hash right in the file and can check it when uncompressing to ensure the recreated samples are the same as the original. Failing that md5sum will do the same thing. Sure applying DSP to the samples modifies them (Thats what it's there for!). Now to be fair, there are a lot of really nasty CD players out there (often sold for 'audiophile' use, that fail to sufficiently buffer things to isolate the DAC clock from the raw disk data rate. You would think that the way to do a CD player in this age of cheap ram was to have the DAC clocked at as close to a constant rate as can be managed and then servo the disk read speed to keep a fifo mostly full. I have seen designs that did it the other way around! Shipping CDDA as a master has always struck me as being fatally flawed as the format is just not robust, far better to ship a file rather then an audio disk. I don't know if there is a standard file format for describing exactly what pits go where on an audio disk, but it there isn't there should be.... Actually arguing for "generational loss" in a digital system is a non starter here, because you didn't qualify that statement. Jitter at the AD and DA clocks is well understood, but is ONLY an issue going to or from analogue, all the other effects described in that paper are down to bit errors during copying which can easily be detected, or DSP doing what it does (with varying quality of results). Better plugins would help, silly things like lowpass filtering the control signals in compressors so as to reduce aliasing in the gain control stage,,,, The real win however is better rooms, instruments, mikes and TALENT. Seriously there are recordings that I will quite happily listen to that have probably less then 50db SNR and are gone by 8Khz, any modern recording chain can do better then that by a huge amount but if the talent on either side of the mic doesn't know what to do with itself then you will not get a result. The tools (with the possible exception of mikes, speakers and rooms. have not IMHO been the limiting factor for a long time. Regards, Dan.

unless you can detect them in a double blind test, they do not exist. this has been hashed to death in audiophile journals for ten years, with those claiming that double blind tests are not needed resorting to all kinds of completely bizarre and utterly dubious statistical theories. first, audio CD "copies" are not "digital file copies" at all. audio CD playback mechanisms have error correction built in, and it is certainly true that making a copy of an audio CD may not result in a "perfect" (ie. bit-level) copy. however, this is not because of the nature of the CD medium (although errors are possible on them; hence the error correction mechanism for playback). if you instead store your audio files on a CD as a data disk using an ISO9660 file system, then any file copies you do *will* be bit- for-bit perfect. this is why you will see cd ripping software such as cdparanoia sometimes run massively slower than "realtime" - rather than using the CD player's audio-based error correction mechanism, it accesses a lower level of the firmware, and is notified of sector read failures. it then re-reads them over and over until it either works or cdparanoia becomes convinced that the disk is unreadable. copying from one .wav to another .wav on a hard drive will never, ever produce any difference of any kind, and if you claim otherwise, you are either completely ignorant of how digital audio works or being deliberately ridiculous. find me one person who can do this in a double blind situation, and we can take it seriously. finally, there is nothing going on in the open source side of digital audio that is technically any different from anything happening in the proprietary side, except that the proprietary side has a few cool algorithms for stuff like dithering. your complaints are not specific to open source digital audio, but are about about digital audio in general. although we have a few wizards of the DSP here, you'd better off in a more general forum (which i am sure will roast claims like "i can hear the difference between two digital copies" as vigorously as anyone here) --p

I Maluvia! I'm sorry I didn't mean to offend you. It's just that *I* happen to be heavily into *certain types* of hocus pocus, and I was hoping to exchange a little bit of subtle humor with you, since you made the impression you'd be at least halfway open to that type of thinking, which is rare! As for the subjectivity, the pages you quoted about the digital myth are based on three things, which are all scientific: 1. CD jitter errors, 2. different types of A/D converters, and 3. recalculation loss. None of these would explain properly why you can hear differences between different copies of files on HARD DRIVES. A/D converters, sure. The sound they are picking up are in an area where quantum physics starts playing a role, so of course there are all kinds of differences to what exactly happens to the sound there. Jitter errors are measurable. You create a mint 44.1/16 WAV file that is your master copy. You slap it onto a CD with your CD writer, that introduces errors because our consumer optical media is fault-prone. You rip the CD on your friend's computer, reading gives more errors, but none are reported, they are simply padded through your CD peripheral's error 'correction' systems. The sound quality is degraded. So far so good. Now say you transfer the whole file back from your friend's computer over a USB hard drive. Now hard drives are fault proof while they last, and when there are errors they are reported immediately. Scan your hard drive with some kind of tool (Norton Utilities used to be fashionable at a time when this was more of an issue than it is now), and you see where there are 'bad' sectors. When you do have bad sectors on your hard drive, bad things happen. Programs crash constantly. File opens fail. You lose data. Your songs start sounding not worse quality, but radio static. You notice it. It's measurable. (In fact, hard drives are not completely foolproof, but that is backed by redundantly storing the data on the disc at the in-disc electronics level, so the computer kernel doesn't even notice... All it gets is a certain series of numbers in, and the same series out. The same things happen when you store software on CD-ROMS, or WAV files on CD-ROMs. There is no error 'correction', errors get reported and if one bit is wrong the disc is trash, immediately). So you take your faulty audio file from your friend's computer, and put it back on your computer using a WAV file, checksums, and generally reliable storage. Your friend's file is inferior, but that is NUMERICALLY MEASURABLE. You run a checking algorithm over the files, and by golly the files are numerically no longer the same, simply because the old CD-AUDIO format is an unreliable way of transmitting digital information, and errors are not reported but attempted to be hidden. Expensive audio players simply happen to be a little better at this hiding process, but transfer your data as WAV files on a USB stick and you don't even need that because you're not trying to fix a two dollar radio with a two thousand dollar solderer. As for all the recalculations and algorithms that get introduced into our audio without us knowing it, yes, this is very common. Everyone wants to throw in a magic formula algorithm to 'improve' what isn't broken, and consumer software often does it without us being aware of it, blatantly ignoring psychoacoustic algorithms don't improve the basic property of digital fidelity, and that is data resolution. But, also, if you'd run an algorithm on an effect-distorted file, it would be numerically detectible. Perfect science. You make the numbers worse, the sound gets worse. So far so good. All perfectly scientific. Now here's where it get's interesting (To me, at least :) You claimed you can hear a difference between two files that are stored on different hard drives. Now that's a completely different story. Hard drives usually store software. There is no automatic error correction with a subtle loss of quality for software. You change a single bit in an executable program, and the thing crashes. It could break your computer, physically, and ruin all your data which represents years of work. In many cases, a faulty program can KILL PEOPLE. Software depends on 1:1 numerical reproduction of data, at least for the lifetime of a computer, and when that's not given, there is no longer a computer, there is only a piece of scrap junk. And yet you claim you can hear the difference between different copies of data on different hard drives. To someone who has been working on computers for more than half of his lifetime, that statement in itself sounds esoteric. So don't be surprised if the man who believes you uses esoteric theories to explain it :) Of course, the phenomenon of subjectivity and energy relations is currently explained within contemporary science as simply a convenient way of discribing trances and other subjective psychological states, which are diverted and deluded and somehow diverted from a generally accepted way of experiencing things. To me, this is a very dogmatic, and also quite arrogant way of looking at things. I don't deny that thinking scientifically is USEFUL, because it enables us to create very sophisticated models of how the world works, which in turn lets us create neat things such as digital audio devices and airplanes and cars. I wouldn't want to make do without all that. But in all its usefulness, that doesn't make the theory TRUE. Newton's theory is useful. It helps explain things WITHIN CERTAIN BOUNDARIES. But then Einstein came along and created a different theory, which had the same results within Newton's range, but continued to be effective when Newton's theory failed. Then Einstein's theory failed, and quantum mechanics was introduced to better explain other and different phenomena. Great efforts are on the way right now simply to bring all those observations to common ground, and when they succeed, we can be certain that YET MORE unexplainable phenomena will occur, and that the theory will have to be placed in proper context yet again. The theory is never true, it is only useful within certain contexts. It's 'true' because it's useful. But it can just as well be untrue where it stops being useful. That's simply the way science works. However, there is a tendency among the scientific community to cling to what already has been explained, simply because it makes things so comfortably predictable. However, that comes at the price of gaining new knowledge, at the price of the very way the current explanations have been found. That's why it is so very important to keep an open mind about things. I was ready to trash my theory that bits are always bits that has worked so well for me for over twelve years AT THE BLINK OF AN EYE, simply because of your unconfirmed subjective observation that you can hear a difference between the same files on different hard drives, even if it might mean making the way I work in the studio infinetly more complex, at least until I found a better theory. That's what I was trying to do there, take my present theory and expand it with new knowledge that a couple of Hawaiian shamans tought me (and my dad gave me a glimpse of when he told me what he and his buddies were up to anno '69) I have heard of people who could PHYSICALLY REPAIR CARS simply by thinking about them. If you think that's hocus pocus, remember that the 'round earth theory' was considered hocus pocus by most only five hundred years ago. Five hundred years! On an earth scale, that's not even one acoustic sample. That's way below any D/A converter's noise margin. We need to stay open about things. Now that doesn't mean I'm getting all hoozy shmoozy on you. If people come to me and tell me all I have to do is think about the pink flame in me and all is well, I tend to mentally put them right where they belong in my opinion, next to cult followers, opiate addicts and battered housewives. What do these three have in common? Unhealthy addictions. But, if new knowledge comes along that has the potential to genuinely improve my life (and that of others), and that knowledge happens to sound different, well. Let us investigate. The statement about the cars no longer sounds so far fetched when you study this guy's work a little: http://www.whatthebleep.com/crystals/ He has people think about water, freezes the crystal, and documents the results. The principles are esoteric (in that subtle energy phenomena are used as explanation) AND scientific (in that the results are reproducable and observable). Wanna create miracles? Do things that are unexplained in our school system. So in my book, no, I do not believe that you are deluding yourself. Bob Moog is said to have had EMOTIONAL CONNECTIONS with his synthesizers, and as far as I am concerned, they sure sound genuine. Maybe that's just the geek me, but I've seen people have really healthy relationships with technology and other 'inanimates'. And maybe that's just the nerd me, but I've seen some really unhealthy ways of people interacting with each other. So I like to joke a lot about technology and people being interchangable relationship-wise. It's a way of getting over a lot of pain. I do not believe you are deluding yourself. I believe you are using your yet unexplained physical properties to influence your environment that could be observed by other people in the same situation also, but maybe not by someone using the same brand but different device as you, or a different person. But that's just a theory. It could be wrong. The remark about your respected partner in the end, on the other hand, was deliberately formulated to be a little edgy, if not theoretically unsound. Please forgive me, I can write impressive essays very well, but I have a very cruel sense of humour that is constantly tempting me. Carlo