physya

Peter Hammil "Over"

I think a chicken was first. Otherwise, God had to sit on an egg to hatch. Obviously, she had other things to do in first seven days, so she created a chicken to sit on an egg. So, chicken came first!

Griffiths is a good text. Also try Richard Feynman's Lectures (I think vol.1) If you want something you can read on the beach, try Enrico Fermi's "Notes on Quantum Mechanics" (but some background (mostly math - matrices and some diff calculus) is still needed). and to understand that QM is not some kind of black magic, read more philosophical (and almost no math) fun stuff, like: "In Search of Schrodinger's Cat: Quantum Physics And Reality" by John Gribbin

So, what was first - a chicken or an egg? (I do have a definite answer, though)

or just play them in SS and record in real time with any recording program (set sourse to wave and disable all system sounds, though). Still, quality is not as good as re-rip...

Aha - gotcha! A=B=C!!! - you admitted it!

How about Porcupine Tree "Deadwing" Dream Theater "Scenes from a Memory" Therion "Lemura"

... and I encourage all interested in science do so, because it was very interesting reading...

Interestingly - Sony Connect sells files encoded at 132 kbps and they claim that they sell CD quality. This means that they actually accept that something less than 132 would be unsatisfactory...

Well, no offense, but there is a difference between exact sciences and all other sciences. I only meant the former. Our alien brothers could have ultrasonic hearing and be deaf at lower frequencies.... I agree that after physical properties are shown to be comparable (spectrum etc) you need to run the acoustic tests to actually enjoy the music. As for decoding - it is an inverse Fourier transform (with some harmonics omited) and it does add some new information - depending on how you handle the algorithm and what precision is used. Moreover, more sophisticated decoders (as ATRAC claims to be) would actually interpolate to fill in the missing frequencies. Anyway, 5 minutes ago I got my MZ-RH910 and now I am struggling to remove that stupid plastic wrap - should probably look for a saw...

Wow! What an interesting discussion came out of a simple question. But, alas, I don't agree regarding that human element. The scientific measurement is such that if I measure something and, say some alien green men do their measurements, they'll find exactly the same as I did (of course, it might require to convert our meters into their feet). However, if we would evaluate music, I really doubt that they would agree with us. Nevertheless, I totally agree that quality is not determined only by the frequency response. It is just a very important objective characteristic. (e.g. see the discussion on how 910 reproduces mp3 cutiing the higher frequencies). That is - if it is very different then you can talk about an intrinsic flaw in the algorithm. So, my point is that ATRAC64 retains quite nicely the original characteristics and the difference in sound quality is in how you decode the stream. It is possible that it actually adds some information during decoding (to compensate for a preceeding high compression). P.S. ... and no, time is not infinite, because it is actually determined by the gradient of the entropy. It begins with a big bang and will either end with another one or stand still when the thermal death of the universe is reached. (I am in physics for some 20+ years by now... )

I meant those sites that greenmachine mentioned in the post above. Of course, you're right about human element etc. By the way, those ABX people specifically mention the "trained listeners" and, indeed, some people will hear what other cannot. I presume that someone with absolute hearing will find the differences for any compression method. However, when you discuss sound of particular instruments, it is not clear what you compare to.Some encoders may in fact enhance these instruments and make them sound better, but I think the best encoder is the one that most accurately represents the original. ... and I am not dismissing the ABX method - I downloaded a program and will give it a try when I have time. "Not scientific" is not negative in this context - it is just not scientific, because it involves human element as a measurement device. as for encoders - it IS all about throwing away non-imprortant frequencies and elimination of redundant information in the stream. The question is how it is done (both ways - encoding and decoding).

Of course it would still sound as noise. The graph is just a power spectrum and has NO temporal information (amplitude vs. time). However, compression algorithms do just that - they simply through away some (least important) frequencies. The question is how it is done. Therefore you can estimate quality of the compression by comparing the power spectra of the same piece of music. I am not familiar with ABX testing and from what I've read on their web page - does not sound too scientific.

What this graph shows is that output amplitudes on particular frequncies are the same, so physically these two waves are almost identical. It could be that you can hear those subtle differences, but to my ears these files also sound very similar - except for high frequency cutoff in ATRAC file. (Although I don't have hi-fi sound - I use Audigy 2 sound card with creative 5+1 speakers) still, please post a couple of unidentified file objects (UFOs) for the blind test.

okay. Attached are FFTs of the MP3 (a) vs ATRAC64 [c] in linear and logarythmic scales. I really do not see much of a difference. The ATRAC is a little bit cut at higher frequencies (as expected). Perhaps, the difference you heard was more psychological. Let's do a blind test. (and with something having higher frequencies)

... don't forget that Napster's subscription files are only 128 kbps (if you set it with DSL) or less if you have different connection (check it in "File/Options"), so you won't get good quality anyway.

That's the point... and this is why the errors can be introduced into a digital stream if sender/receiver do not have error correction protocol. I just think that not everybody realizes how much cable traffic is used for this correction to keep "digital be digital".

Indeed, optical is much better ... for trans-Atlantic communication. At home, the conversion of electric to optical and cable bending are bigger problems than electric noise. (Good) coaxes are good up to MHz frequencies. As for CD vs HD etc. You again forget the error correction built into any copying process. I think the following will be useful for all this "digital is digital" discussion: (taken from CD-Recordable FAQ) -------------------------------------------

...and (to be completely paranoic) then you should make sure that both devices properly grounded and there is no ground loop. (not a joke - there is NO good ground in a normal household). ... and yes, you want to make sure that cables are properly terminated at 75 or 50 Ohms...

Yes, you're right. I was reading more and apparently everybody comes accross this 1 minute problem. Besides, Hi-MD Renderer works just fine. I should have checked before starting this thread...

I had this problem. Then I uninstalled and removed SS directory. Rebooted computer and installed it all again. It worked. Later, I removed that and installed a non-Connect version available in the download section. It worked just fine.

or it could be a kind of lightly compressed "buffer", so that decoder could read ahead and decode the rest. Then this buffer could be in a recognizible format, whereas the rest is in special ATRACTplus.

Wow! - You ARE right! Goldwave actually only opens exactly 1 minute 2 seconds - regardless the format or bitrate of the initial file. This calls for further investigation...

What do you mean half file? If you got XP "program will be closed..." popup - just ignore it - GoldWave will continue (strange, but fact - I had it once with Audible files). I don't know what format of OMA files I have. I used SS 3.1 and chose the 256 kbps. I think it must be ATRAC3plus (I also tried ATRAC3 at 132 kbs). I converted a whole CD from WMA to ATRAC and then used GoldWave to batch convert it directly to MP3. The end result was almost identical (qualitywise) to the original.

Well folks, this is not as simple as it looks. I mentioned error correction and rejection buil into any file transfer protocol. The actual amount of information is about 1/5 of all traffic - the rest is used for the error correction. I don't think the recording uses same thing. Now, certainly noise have frequency dependence. Usually it is so called 1/f noise, so your low frequency is more affected. On the other hand, the surrounding is full of high frequency stuff and tends to have elevated noise at higher frequencies. Coaxial cable is a pretty good shield up to few MHz frequencies above which you have to use solid stainless steel coax with SMA connectors to completely suppress noise. I can actually beleive that coaxial is better than optical, because transformation of electric to optical and backwards is potentially a source of errors.