Some technical debates are so polarised that it is hard to believe there can be sane people on both sides. One such is that over whether high resolution audio is audibly superior to CD.
First, a little orientation. A standard redbook CD stores music encoded as 16-bit PCM (Pulse Code Modulation) sampled at 44,100 Hz. This standard was first published in 1980 and the first production CD player appeared in 1982.
Technology has moved on a long way since then, and around 10 years ago there was an industry format war over what higher resolution disc should replace CD. Sony championed SACD, which uses Direct Stream Digital, a 1-bit system with samples at 2822.4 kHz. Meridian and the DVD forum supported DVD Audio, offering a variety of possible formats up to 24-bit PCM sampled at 192 kHz.
Bigger numbers, better quality, right?
The 16/44 transparency test
Maybe, maybe not. Some audio engineers maintained that even 16/44 was more than adequate to convey audio with an accuracy greater than the limits of human hearing, at normal listening levels. In 2007, Brad Meyer and David Moran put this theory to the test. They conducted a series of listening experiments using high-resolution sources, testing one simple proposition: if you convert the audio signal to 16/44 digital and back during playback, is the difference in quality detectable?
Meyer and Moran wrote up their results in a paper published by the Journal of the Audio Engineering Society. Unfortunately the full paper is only available to AES members, but the results are well known and widely discussed. Their tests, which used double-blind testing techniques where neither listener nor tester knew which signal was being played, showed that no listener could reliably detect when the additional 16/44 conversion was inserted into the signal path.
On the face of it, this shows that no matter how good a stereo SACD or DVDA disc sounds, it could also be encoded onto a CD and sound the same to human ears. There was an unimportant caveat. If the volume was whacked up to very high levels, you could hear a difference in the noise floor.
What the transparency test does not prove
It’s worth noting that the Meyer/Moran test only covers one point: that 16/44 is (or is not) acoustically transparent. It does not prove that high-resolution audio is pointless; in fact, it has obvious value in production (as opposed to delivery), since production means digital processing, which degrades the sound; it makes sense to work in a resolution much better than you need for final output. I guess the same argument can be applied even to the distribution format, if the player is processing the sound to apply equalisation or bass management, for example.
Even if the test result is correct, it may still be that SACDs sound better than the same music on CDs, maybe because it is mastered better, or the player performs better with SACD, or maybe better source tapes were used for the SACD. In fact, Brad Meyer says:
Those who have read the JAES paper written by me and David Moran may remember that we too thought that the high-bit recordings we heard sounded, as a class, really exceptionally good. Our experiment, however, made a very good case for the theory that the reason for this lies not in the extra bits but in the market niche these recordings occupy.
Your rant against what you call square-wave recordings (i.e. ones in which the dynamic range is very heavily compressed to make the average level higher, which is a common mastering practice) is one I quite agree with, but it too has nothing to do with the number of bits in the recording. Our experiment showed that those awful-sounding things could just as easily have been issued as SACDs — and conversely that the excellent sounds we heard from our test material could have been issued in 16/44.1 without audible degradation.
Here’s how I think it works. SACDs are issued to a tiny niche market that is known to use good to excellent equipment, and to be fanatically devoted to realistic timbres and dynamics. Because the big guys in the record companies don’t care at all about such a tiny niche and are financing these SACDs because it’s the modern thing and sort of prestigious (and the other companies are doing it), they leave the engineers and producers alone, and the latter just make the stuff sound good on their own studio monitors and good home systems, and send ’em on out there.
And guess what? If a skilled engineer has as his only goal making something sound good enough to show off to his colleagues, you’re gonna think it’s pretty damn good too.
It is also worth mentioning that both SACD and DVDA are not solely about high-resolution stereo. They are also for surround sound, something which a CD does not support.
In a nutshell: you could agree with the test result and still want to invest in SACD discs and hardware.
Does it matter?
Does it matter? Well, a considerable part of the marketing behind SACD and DVDA is that the sound quality is better than ordinary CDs. Unfortunately Sony has back-pedalled so much on SACD that I can no longer find its marketing material online; but it emphasised that Direct Stream Digital is more analogue-like than PCM as well as higher resolution. I am not focusing here on the benefits of DSD over PCM, which are also contested, but will mention that the transparency test casts doubt on this as well as on high resolution sound itself. This is from a leaflet tucked into early SACD releases:
The SACD format is about to change the way you listen to music … thanks to an amazing 2,822,400 samples per second, you get audio performance that no other format can deliver. Where CD frequency response extends to 20,000 Hz, DSD technology can theoretically reach 100,000 Hz. Where CD has dynamic range of 96 dB, DSD recording can achieve 120 dB across the entire audible range. Thanks to DSD technology, the SACD difference is breathtaking. If you care passionately about music, then SACD will inflame that passion as never before.
and
Unlike multi-bit PCM recording, SACD’s DSD technology uses a one-bit pulse that is analogous to the music waveform.
You can also get a flavour of it here, an unofficial FAQ, including this statement:
…the difference between regular audio CD and the high-density layer of SA-CD can be quite easily perceived, even to untrained ears
There is still an SACD market, though the format has disappointed in an absolute sense, and Sony (and others) still sell high-end SACD players. There are also audiophile sites where you can purchase high-resolution downloads, such as HDtracks and Linn Downloads. The high resolution downloads cost more; so if nothing else, Meyer and Moran might save you some money even if you want the best no-compromise sound.
Industry and community reaction
Meyer and Moran’s paper has been widely debated, though considering the implications for high-end audio perhaps not as much as you would expect. Many audiophiles simply disbelieve the result. They are happy that earlier papers such as this one [pdf] by J Robert Stuart of Meridian present technical arguments why 16/44 is not enough:
The CD channel with 44.1kHz 16-bit coding (even with noise shaping to extend the resolution) is inadequate. Even 48kHz sampling is not quite high enough.
Hi-fi critic Robert Harley says that the conclusions of the test prove that double-blind testing does not work:
Every few years, the results of some blind listening test are announced that purportedly “prove” an absurd conclusion. These tests, ironically, say more about the flaws inherent in blind listening tests than about the phenomena in question.
The latest in this long history is a double-blind test that, the authors conclude, demonstrates that 44.1kHz/16-bit digital audio is indistinguishable from high-resolution digital. Note the word “indistinguishable.” The authors aren’t saying that high-res digital might sound a little different from Red Book CD but is no better. Or that high-res digital is only slightly better and not worth the additional cost. Rather, they reached the rather startling conclusion that CD-quality audio sounds exactly the same as 96kHz/24-bit PCM and DSD, the encoding scheme used in SACD. That is, under double-blind test conditions, 60 expert listeners over 554 trials couldn’t hear any differences between CD, SACD, and 96/24. The study was published in the September, 2007 Journal of the Audio Engineering Society.
I contend that such tests are an indictment of blind listening tests in general because of the patently absurd conclusions to which they lead.
Reactions like this are to be expected from parties that are heavily invested in the merits of some facet of technology. Hi-fi is particularly problematic for several reasons, for example:
- We have difficulty in separating our enjoyment of the music from the quality of the technology.
- There are known placebo effects which make sighted tests suspect. Our brain tells us something should sound better, and therefore it does sound better; even if science or blind testing later proves that it was not for technical reasons.
- Differences such as a slight increase in volume may be perceived as an improvement in quality; hi-fi demonstrators are well aware of this. Exact matching of volume is difficult to do at home.
Others have advanced different reasons for the Meyer/Moran results. Perhaps the equipment was not good enough. Perhaps the testing was not rigorous enough, or they used the wrong source material. The test authors posted some more information so that others could form an opinion about this. The equipment looks reasonable to me, though it is not at the ultra high end of hi-fi.
Still, what is surprising is that (as far as I’m aware) nobody has repeated the tests correcting such flaws and obtaining a different result. Of course that may yet happen; but the lack of such counter-tests so far strikes me as equally as significant as the test itself.
I asked Harley about this and he replied:
I’m not aware of any formal DBT of standard-resoution digital audio with high-resolution digital audio. The difference between 44.1kHz/16-bit digital audio and 176.4kHz/24-bit is obvious, in my experience. It is, in fact, so obvious that no one (no one that is a disinterested experimenter, that is) has bothered to organize and conduct it.
Your last sentence reminds me of the cartoon by B. Kliban showing a professor at a blackboard full of mathematical equations in front of a classroom in which all the students are fish. The caption is “Proving the Existence of Fish
Is it obvious? The resources section below offers some samples in both 16/44 and 24/96 that you can try and I’ve also done my own experiments, though comparing such samples is not quite the same test that Meyer/Moran conducted. I’d contend though that the difference is not so obvious that it needs no argument and I would not put money on my ability to tell them apart under blind conditions.
Mastering matters more
The Meyer/Moran test is persuasive, but I am open to the idea that some further research may prove it to be not the last word on the transparency of 16/44. Still, I’d expect the audible differences between 16/44 and higher resolutions to be subtle at best, and I am sceptical of any claims otherwise (like Harley’s above).
A bigger concern is that the focus on high-resolution formats, or minutiae like whether an SACD player converts DSD to PCM during its output processing, distracts from what matters more: the way the music is recorded and mastered.
Thanks to the ongoing loudness wars some audiophiles seek out early CDs from the eighties, or even vinyl records, to get the best-sounding versions of favourite albums. Some of those old CDs do indeed sound stunningly good; not only because of greater dynamic range, but also because a light touch was applied to mastering in the early days so that a CD was close in sound to the master tape. Not all old CDs sound good of course; sometimes bad tapes were used or damaging noise reduction applied; but the fact that some twenty-year old CDs can out-perform modern pressings shows that mastering decisions count for more than digital technology or resolution.
Resources
The Meyer/Moran paper with brief discussion
Discussion of Meyer/Moran paper on AVSForum
Discussion of Meyer/Moran paper on Hydrogenaudio
HDtracks offers a free sample of various styles of music in both 16/44 and 24/96
Sample from Barry Diament’s Soundkeeper Records comparing 16/44 to 24/96
Tim, I’m not sure how old this article is, but I do have some anecdotal experience with this.
I have one of the early model playstation 3s (the ones that still supported SACD playback) and a few discs that have both CD and SACD layers on them.
I re-purchased a couple of my favorite albums to see if I could tell the difference, and my partner (who was 2 rooms away) said she could tell the difference from there. Having studied music and heard her sing, I can tell you she is totally tone-deaf.
This was on one of the cheapest surround sound systems available (AUD$1200 for receiver and speakers). Even though it does HDMI switching, it can’t even decode the audio from HDMI. I have to play SACD through stereo analogue cables. The PS3 is far from being a top-of-the-range SACD player as well.
But the difference is positively startling. I used to think the sterile sound from CDs was the digital format itself. But my experience with SACD totally disproves that.
I also agree with the comments about double blind tests. Human perception is totally malleable and we even change what we perceive as we perceive it, based on our own expectations and prejudice. But when you experience the same album in two formats back-to-back, the differences are very clear between SACD and CD.
None of that makes music on CD (or MP3) any less enjoyable, but given the choice I’d go SACD all the time, same as I’d choose 1080p (or higher resolution) video over 720p or SD any time. I just wish the catalog of SACD titles was larger and the discs were cheaper (same with Bluray).
@Craig one of the problems is that the CD and SACD layers may not be mastered to sound the same. The CD layer may be more compressed – to sound more like other CDs. Another issue is that any particular machine may perform better on SACD vs CD. There are too many variables; which is why leaving the playback source as-is and inserting an additional conversion loop is a better way of testing im my opinion.
Tim
@Tim: I definitely agree with the point about mastering decisions and sources.
The simple tests I performed were done with two discs. One was Norah Jones, which has both SACD and CD layers, and the other was Pink Floyd DSotM (using separate discs). I would expect the mastering choices on the first to be nearly identical. But DSotM would certainly be different as the SACD was re-mastered for multi-channel output.
It’d be interesting to repeat the test again with a decent receiver and speakers. The most surprising thing I found with SACD was the level of detail in the audio. You could hear sounds in the SACD version that didn’t exist in the CD version, and the spacial quality of the audio was miles apart (no pun intended).
I understand how convincing this kind of test can be. At the same time, it is hard to think of any technical reason why going from 16/44 to hi-res would make new sounds audible, other than mastering differences not related to the difference in digital resolution.
The thing to to is to take the high-res audio, convert it to 16/44, then do a blind test between the two. Or better still, insert an additional 16/44 loop in the signal as in the test referred to in the article.
Tim
Just a note to the poster above re: Norah Jones SACD.
If you’re comparing SACD & CD layers of “Come Away With Me”, the SACD layer is supposedly a DSD copy of the CD layer! Therefore, there should be absolutely NO difference (at worse, the PCM –> DSD conversion degraded the sound!).
See here:
http://www.stereophile.com/thefifthelement/1104fifth/
Hello. This is a very interesting topic here. I wanted to compare PCM sound to SACD before too. I took the Norah Jones SACD layer and recorded it onto DAT at 16bit 96KHz. Even at that high sampling rate the SACD is still much clearer with alot more realistic sound. The sounds are definitely more true to real life. Hands down SACD won over the PCM.
Just to add my ha’penny worth to the debate. I’ve been using cd, minidisc, sacd, dvd-a, cassette and vinyl in a modest but fairly revealing hi-fi set-up for many years. The first eye-opener (or should it be ear-?) with regard to high resolution audio was an SACD of Toto’s album IV. The first track (Rosanna), revealed a constant cymbal riff that I had never before heard on radio, cassette, CD or LP. Knowing it’s there now, I still have great difficulty hearing it on CD if at all but it is crystal clear on SACD. I’m pretty certain it’s not due to any sort of remix, as the overall sound is almost identical except for the increased level of detail and seperation of instruments that I have noticed with the higher resolution of SACD.
Another album that has bowled me over is the SACD of Al Jarreau’s All I Got . The sound is so lifelike that it’s spine-tingling. There are 3 elements which immediately stand out: first the crispness, punch and complete start-stop of each element of the mix – there’s no overhang, it just stops dead where it should as in real life. Secondly the fullness and warmth of the sound – it feels like there are no limits to the deepness of the bass and the treble extension (apart from my speakers limits). Lastly, the sense of space around each voice/instrument, as though the whole atmosphere has been captured, not just the sounds.
My other favourite album is the RPO’s own SACD of Rachmaninov’s 2nd Symphony. The realism of the orchestral instruments is stunning, and the music builds and builds into a climax that goes way beyond any CD I have heard (and I have a LOT of classical CD’s).
However, now for the downside. I suspect that record companies are using SACD (and the dying DVD-A) simply as a way of presenting surround sound versions of albums, without significantly increasing the resolution. Thus a DVD_A of Fourplay sounded exactly the same as the CD version on 2 channel audio. Some recent SACD releases (and remixes) of Elton John and Genesis have to me sounded more compressed and harsher than the original CD’s.
So we may eventually see the demise of true high resolution stereo on SACD and DVD-A in favour of CD quality surround sound!
Ant
Thanks for the comments. I know that there are many SACDs that sound great, but that doesn’t answer the question of whether this is to do with hi-res itself, or just that the recording was better mastered or from better sources, or some other factor. This can’t be resolved without rigorous listening tests in controlled conditions, of which there are few.
Tim
Just found this, so I’m joining the discussion late in the game.
1. If you hear “details” in the SACD that you have not heard on the CD, put the CD back in the player and see if you hear those details now.
Maybe you just didn’t notice and were listening more carefully to the SACD… 🙂
2. I have a reasonably good, but not top of the line system (no SACD though). Some time ago I was given (a sort of indefinite loan from a good friend) a pair of Tara Labs Air RSC 1 interconnects.
Without delving too deeply into a discussion on cables, the amount of additional detail, depth and “air” I heard on the same CDs was breathtaking. Really.
I would have always thought (I’m not an engineer, just a moderate audiophile) that a higher sampling rate simply makes the digital sine soundwave less jagged, so the sound is more “analogue”. Amount of “detail” does not necessarily have anything to do with it.
@Pawel
It doesn’t work like that. There is nothing jagged in the wave; but it is frequency limited. However the additional frequencies that can be reproduced by high-res are inaudible by humans.
Tim
Additional problem with SACD is no possibility to RIP to the disc. After many checks I have now really good system to listen from by server database (based on Ayre QB-9). For me it’s better (more “analog” and detailed) than SACD content from rather good SACD player. Unfortunately, I don’t know the procedure, to rip convert SACD to 24/96 PCM, so in this case I cannot compare SACD and CD source.
Hi Tim,
You and your readers might be interested to know the Soundkeeper Recordings Format Comparison page now includes 192k samples (in addition to 96k and 44.1k) from our latest release Equinox.
Best regards,
Barry
http://www.soundkeeperrecordings.com
http://www.barrydiamentaudio.com
I’m not convinced that a double blind test where you are asked to identify between A and B is necessarily definitive. I may not be able to tell consciously which is which in a ‘laboratory’, but perhaps in the right surroundings and ambience and listening to the right music, I might only find the hairs on the back of my neck standing on end with the higher resolution format. Or maybe my ears may simply be less ‘tired’ with the 24/96 allowing me to listen for longer, louder. It’s impossible to measure and prove it though.
My guess is that 44 kHz is uncomfortably close to the limit for the desired 20 kHz response, so that there may be strange effects going on right at that top end. And even if our adult ears can’t hear those effects as such, they may be able to hear them when the high frequency components present in the two stereo channels ‘beat’ together in the air before reaching our ears. So if I had to bet on it, I would guess that there is some value in stretching to 24/96, but that it may never be demonstrated objectively.
Technically, DVD-A (this is NOT a DVD movie with a music layer on it) should be far superiour. Only it is DEAD. The biggest mistake in my opinion was the choice of the name : DVD-A Most of the people (also technicians and engineers) were not aware what DVD-A was in fact…The standard supports up to 24bit/192 kHz in stereo and 24 bit/96 kHz in surround 5.1. (SACD : only 1 bit datastream / 2.822.400 Hz)
There seems to be something missing from the ABX testing of most stuff which is that it isn’t real ABX testing. There’s no control for the aptitude of the subjects. What I mean is: they need to test each subject to see which things they CAN discern in the test environment before doing the test. So then you could say “of the 500 subjects who could reliably tell a U-87 from a 414 100% of the time, none of them could tell when 44.1/16 conversion was inserted into the same chain”. Without that, it seems meaningless. Not everyone can hear stuff in a test environment. If you get the result that also nobody in the world can tell the difference between microphones, etc., then either everything in the world is fake or there is a problem with the test. It seems like a lot of times people think they are supporting “the scientific method” but really they aren’t using. Real scientific method would be to look at lots and lots of situations and then analyze the data…
An interesting point, though most people assume that because differences in things like loudspeakers (and, I would have thought, microphones) are easy to hear, the ABX isn’t worth doing. But I’d like to see more of these kinds of tests.
Seems plausible to me. I have a small collection of hi-rez recordings and I think they sound better. When I downsample them to CD I am not that sure I can hear the difference. I think I can, but I would not bet on it in a blind test. Most differences probably are in the mastering. One reknowned writer carries CD-R’s recorded from his megabuck turntable that are purported to sound massively better than the commercially released CD’s. This is supposed to prove the superiority of the vinyl LP. Most people don’t seem to see the lack of logic in that.
Dear Friends, I am an audiophile with modest but good equipment from the era of the Vynils. For many years i feel something wrong happened with the normal cds. Sometimes i thougt it was a problem with my speakers, or my ecualizer. With the arrive of the mp3 an other formats of compressed music, the things for me went worse. Recently a have heard some titles in 24 bits 96 khz and feel the soul was returning to my body with that format. But yesterday i could hear with foobar 2000 the record “getz and gilberto” from 1964 in dsd format from a sacd, and is the first time in many years that i could feel the music the way a did in the past with a good analogue equipment, it is like the real world of sound. I hope that the sacd format be more accequible in the future because it is the real thing. Note: excuse me for my english
What format is the getz and giberto file as played by foobar?
Tim
I’m a little late here, but want to make a few comments.
1. Most modern CDs and other recordings have their dynamic range modified (loudness wars). When I compare a high quality Frank Zappa LP to his same 90’s CD there is about 10 dB or more dynamic range on the LP (when checked using Adobe Audition tools). You will almost always enjoy the LP more than the modern CD. However, LPs introduce other distortions such as S-filters, bass reduction to pack the grooves closer, feed-through from adjacent grooves and feed-back from loudspeakers. These are still not as bad as dynamic compression. There is no easy way to compare LPs and CDs, but more dynamic range will usually sound better (can be played louder and you will hear more going on). Also, most computer A/D boards introduce high frequency noise peaks as well as digital noise from the computer, so the quality of your recording setup can affect results.
2. LPs do sometimes have sound beyond 20 KHz, but it most likely is harmonics generated by the needle shank and magnetic non-linearities. The RIAA filters tend to roll off quickly above 20 KHz and aren’t really defined beyond that region. I copy my LPs to 96K/24 for repeated listening, but this may be overkill.
3. When comparing 192 KHz or 96 KHz 24-bit recordings to 44.1 KHz 16-bit you need to consider the source of both. 44.1 KHz doesn’t divide evenly into the higher bit rates unless you use 88.2 KHz for the master. Most audio conversion programs used on personal computers are not designed correctly to convert either the frequency sample rate nor introduce proper noise shaping at the 16-bit noise floor. They will introduce distortions that some golden ears may be able to hear. Most modern recordings only use the top 20 dB of the sound range and you won’t hear this distortion in a 16-bit source. If you listen to a good recording of Stravinsky’s Rite of Spring at high volume, almost any one should be able to tell the difference between 96K/24 and 44.1K/16, even with old ears like mine, because the quite passages will be colored by the quantization noise. But then again, it could simply be poorly written conversion software.
There are a lot of other factors that can color your sound experience, even with proper ABT.
You can find some interesting reading on conversions here:
http://www.channld.com/pure-vinyl_src.html
Good article and although an older topic, I just wanted to chime in here about the fact that digital ripping of SACD’s can now be performed with older model PS3’s with the appropriate firmware.
Bottom line is that about 20-30% of all SACD’s were sourced with 44kHz masters (obvious in the spectral analysis with 22kHz hard cutoff of frequencies). Examples:
Norah Jones – Come Away With Me (widely publicized)
All MFSL Dead Can Dance SACD’s
Baby Face – The Day
Eugene Ruffolo – Santa Sings The Blues
Beoga – Live in Studio
MFSL Cowboy Junkies – Whites Off Earth Now!! (original 16/44 digital recording anyways)
Weather Report – Mysterious Traveller (the multichannel mix was 44kHz)
Thankfully many of the classic SONY SACD’s like Kind of Blue, Take Five, Straight No Chaser are good looking analogue transfers…
These are just a few I bothered to keep track of especially from audiophile labels (like MFSL and Stockfisch)… Numerous others were suspicious as well.
Yes, different masters are being used for the SACD vs. CD layers as well – an example would be John Mayer’s Heavier Things (2003) where although both layers are dynamically compressed, the CD layer was worse.
Bottom line – ya never know what you’re getting with these SACD’s. Sound quality comparisons remain extremely difficult especially since probably almost all studio recordings and multi-track material have at some point gone through a PCM -> DSD conversion step along the line which probably has caused some sonic degradation already (may not be all that audible).
Enjoy the music 🙂
One more thing… Not to just pick on SACD, DVD-A also has its issues with many of the releases. A good example I came across is R.E.M. “Around The Sun” which came out in 2004, during a time when the major record labels were pushing for hi-res and surround music adoption. It wasn’t until 2005 that DVD-A could be digitally ripped.
On this album, the high resolution 2-channel audio was 24/88 but in fact this was upsampled 24/44. The dynamic range is slightly better than the CD release, so for those who like this album, this 2 channel mix is the one to get. The surround mix presented in 24/96 is much better with excellent dynamic range and was not upsampled! Why they could not have used a true high-resolution 2.0 presentation is a mystery…
It’s going to be interesting what the future holds for high-res music. For those who have downloaded new pop / rock releases from the net (eg. HDTracks), have a look at the dynamic range with something like the Foobar Dynamic Range plugin. Many of these 24-bit releases have DR’s of 7 to 9 (eg. Joe Walsh “Analog Man”, Muse “The Second Law”, Steve Hackett “Genesis Revisited II”, Smashing Pumpkins “Oceania”); no better than the respective CD and not deserving of 24-bits IMO. Even if high-res audio CAN sound better, what’s the point when the mastering effort remains so poor?
James, re your point 4, a properly mastered CD won’t exhibited any quantisation distortion at any output level. Dithering and noise shaping eliminates quantisation distortion, shifts the noise into less audible regions and increases dynamic range. On a good CD, the quietest parts of your Stravinsky even played very loudly should just have gentle background hiss at maybe – 106 dB down. If you have the volume such that you can barely hear the background hiss, that’s probably about 30dB. So the loudest sounds could be 136dB, ie. blow your head off. Far louder than any orchestra under any conditions. What I am really saying is that CD has more than enough dynamic range to reproduce any orchestral music without audible distortion.
Of course the producer could butcher the mastering, but the format itself should not be a problem.
Can I ask a really simple question? If you’re are attempting to replicate a 20kHz sine wave with 44k samples per second you will only have just over 2 samples per cycle.
So if you happen to sample on the peak you get loud 20khz square wave, but if you happen to sample as the sine wave crosses zero you get nothing.
Therefore have 4 sample per cycle, like 96kHz would seem very beneficial.
@PabloP have a look at this video:
http://xiph.org/video/vid2.shtml
Tim
Tim’s statement that it has a lot to do with mastering si likely to be true. In the analogue era the quality of the LP dependent upon the quality of the recording gear and could already record inaudibly high frequencies. As everything above 22kHz would fold down in the audible spectrum due to aliasing a analogue low pass filter had to be used to bbecame e able to digitize this. In these filters the reason lies for the deterioration. Probably nowadays still a lot of recordings are made that way. When higher sampling rates became available these filters became much easier to implement without sacrificing much audible quality anymore. After that downsampling to the redbook format is a breeze and will hardly impact audio quality anymore. Only those persons with really golden ears wil hear that frequencies above 11kHz are not so neatly shaped anymore, although most modern upsampling CD players will fill those gaps nicely and make the effective analogue output signal hardly distinguishable from the hi-res result.
Conclusion is that without the SACD and DVD-A development this improvement for the normal redbook CD would not have been achieved. And as said above, probably a lot of redbook CD’s are still made going directly from analogue to 44.1kHz and sound therefore mediocre.
hello….has the new cd players made improvements in cd sound as far as more accurate delivery? I don’t know who to believe anymore with all this external DAC talk and stuff. What amazes me in a quisitve way is that many of the improvements made in video is clearly detectable…no blind test (sorry for the pun) necessary. If Hi Rez was really what it purports to be, there woulden’t be any need for blind tests…we’d all go WOW..but we don’t..so, using that logic, it’s not an obvious, if any, improvement.
A good thread, attended by individuals who really want the truth. But Robert Harley’s comments are profoundly discrediting. I don’t know Mr. Harley and had no prior reason to like/dislike or respect/disrespect him. Now I do! To summarily indict double blind investigation (widely viewed as viable method of inquiry) as baseless, then follow with an absurd fish cartoon speaks volumes about his qualification (i.e. lack thereof) to even participate in this forum or in others of its kind. Let’s have him tune up his golden ears and subject them to scientifically viable scrutiny. Until then, I’ll ignore everything he writes.