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Let's for convenience sake agree that SACD sound is indeed superior to RBCD.My question: is SACD sound still superior to CD sound if the latter is delivered in digital form to digital processing and amplification equipment?
My personal experience tells me that SACD sound fed into a traditional analog chain is inferior to RBCD feeding into a digital (TACT or Behringer/Panasonic) upsampling system unless...
...maybe unless the analog chain is of the highest (costliest) type.
Follow Ups:
Whichever format you choose, the least amount of manipulation to the original content is your best bet.
The best bet to what? Only to hear what is factually on your medium,
but do you really want that?Let's look at it from a scientific point of view. Here are some facts:
* The ideal: The analog waveform of the music you intend to hear.
* The cripple: The 16bit 44kHz reduced version of that material (RBCD)
* The alternative: SACD, 2,8224 MHz of 1 bits.
* The improvement: RBCD run thru an upsampler to make 192/24 out of it.The cripple may sound interesting, but it is surely not close to the
original material.Let's look at SACD. http://en.wikipedia.org/wiki/Super_Audio_CD
suggests the format can at best be compared to a 88 kHz 20 bit
stream. That would be quite good.The improvement: Upsampling means soften out the edges with
mathematical spline emulation. This will help restore the original
softness of the recording, but of course it cannot re-introduce
any level of detail that got lost when rendering to RBCD format.Mathematically, there is no doubt both SACD and upsampled CD must
be superior to the lo-res RBCD format. Which one gets closer to
the original is hard to tell. Mathematical tests could show.
This could be done algorithmically if the SACD encoding and decoding
algorithms were available. Alternatively you could try comparing
the waveforms in an oscilloscope.Mathematically it could also be determined if upsampling SACD
should lead to even better resemblance to the original waveform,
or if it is already in a range where it is no longer useful.
This should be empirically determinable, but I'm not spending
time and thought on that now.When it comes to digital vs analog amplification, we leave the
grounds of empiric knowledge again. Analog is likely to sound
more pleasant, digital is likely to tell you the truth, wether
you like it or not, but that's just my opinion.I gotta get me a soundcard that delivers 192/24 straight, so I
can output my own music productions directly at that bitrate
without any conversions. That would be superior to all 4 options
above.Unless there is some other problem with it, like, hello jitter,
as I wouldn't have a synchronized link between the soundcard and
the digital amp. HDMI would help though, if there was an HDMI
card that could transmit audio at such a high rate.Yeah yeah always striving for perfection.
(And yes, I left out the problem of room correction, but we talked
about that in other postings more than enough).
HowdyUpsampling is just an alternative implementation of the Redbook reconstruction filter. There is no new info, nor (in a purely mathematical sense) a smoother result. Now the fact that there is a lot more freedom in filter selections available after upsampling gives a lot of room for optimizing, say, amplitude response or frequency response, etc. but there is no other mathematical superiority of upsampling.
Also spline interpolation is not the proper method of filtering after upsampling. (I'm not saying that a few companies don't do it, but it's not the standard way and most upsampling chips certainly don't do it.)
You are also wrong about upsampling Redbook being superior to SACD from a mathematical point of view. SACD has four times the bit rate of Redbook. Upsampling adds no new info to Redbook so upsampled Redbook is still at an approximate four to one disadvantage in info compared to SACD.
I agree that higher sample rates are (in general) a good thing. The problem you are ignoring is that it's impossible to implement a technically correct PCM reconstruction filter so everyone picks a different compromise, some better to some, some worse to others. I happen to like SACD's approach of avoiding the problem.
-Ted
"You are also wrong about upsampling Redbook being superior to SACD from a mathematical point of view."I didn't say that.
You answer before you read, huh? :)
I was just suggesting that whichever format you choose it will sound better by playing it back in the same format that it was pressed to.For instance, you would not record a vinyl record to 1", 30 ips reel to reel and expect better than vinyl sound just because the tape machine is better than the turntable. No, you would just play the record in real time and listen to it. That's as good as that can be. Just the same, you do not gain anything by upsampling and artificially filling in missing information that does not exist in the first place from a 16/44 CD. A 16/44 CD is what it is. No more, no less. If it was recorded in 24/96 all the way through (it's SACD), then sure, you should play it back that way. But then you're not upsampling either, you're just playing it back.
It's interesting now, with all of these choices we have in A/D converters. You can choose almost any combination of bits/sample rates when you lay down a track. But in the end you have to decide which format you want to use to distribute your recording in. I think this is where a lot of musicians/mixers and mastering engineers get lost. They figure the same as you. "I will pick the highest bit rate and sample rate and then move it all down to redbook at the final step." This is a real shame. If the end goal is to make a 16/44 CD, then recording it straight to 16/44 sounds better than a 24/96 mix that's been dithered and SRCed down to 16/44, and then upsampled/dithered back again by the user. This has been my experience anyway.
But of course, we do agree to disagree. It's fun though, isn't it?
I am a bit lost here. We all agree that CD sound is edgy. But is it really because 16/44 does not offer enough bits to record all subtleties of music?I remember having read over the years several statements stressing that 16/44 offers enough bits and there was no need for hi-rez formats. If that is the case we are chasing the wrong cat.
Could the chief culprit be the 20kHz brickwall filter which makes CD sound edgy? Could it be that upsampling allows to soften the brickwall and make CD sound similar to current hi-rez formats?
Ever since I left the oversampling world I haven't really thought about "edginess" during CD playback. When I do hear an underlying digital signature, it's usually due to the sample rate conversion, dithering, or other bad decisions made during the process of creating the CD master.That's a whole 'nother can of worms . . .
It just moves it to a different place, which means you now have two digital filters in play instead of just one. Some like the sound better, some don't. DSD upsampling is a little different because it's really just a refinement and renaming of the oversampling delta-sigma process that's been used for years with bitstream D/A convertors.
HowdyNope, there aren't necessarily two filters, upsampling only requires one filter and its whole purpose is that that filter doesn't have to be a "brickwall" filter, i.e. it can have a much gentler slope.
-Ted
Call it what you want, but most implementations involve using an upsampler with a brickwall anti-alias filter for the base sample rate followed by the "normal" digital filter. Of course the normal digital filter can potentially use a higher cutoff point and/or gentler slope at the higher sample rate ...
HowdyYes many implementations these days use separate chips for the upsampling and the DAC proper. This isn't necessary for an upsampling DAC but it's easy. BUT the upsampler doesn't use a brickwall filter, its whole purpose is to avoid that. It uses a gentler digital filter implemented in the higher sample rate whose stop band starts at the nyquist for the lower sample rate. This doesn't need to be a brickwall filter. Then at the DAC proper since the input is already bandlimited the DAC can be configured to use a gentler reconstruction filter as well and once again a brickwall filter is not needed.
-Ted
I thought the upsampler stopband was still dependent on the input sample rate. Nevermind then. So on something like the CS8420 where they spec the bandwidth as .4535 * input sample rate and stopband attenuation as 110 dB, they are saying that if I play a CD and have my CS8420 output clock set for a 88.2K sample rate, the bandwidth extends to 20K and the stopband attenuation slope would be about 110db /octave instead of a brickwall? Seems like everyone would jump on upsampling if it was so clearly superior from even simple technical specs. Hmmmmm ...Thanks for the info, Ted.
HowdyYep, simple upsampling has clear advantages in allowing saner reconstruction filter designs. In the purest sense, the transition band starts at 20KHz and can stop at the output rate - 20KHz, there are often other considerations in an actual part. Still a 110dB per octave filter is nothing to sneeze at. That's why there are 4x, 8x and higher oversamplers.
But everything matters: power supplies and isolation, filters, analog outputs, billions of details in the DAC...
On the other hand I still need to hear some of the filterless DACs outside of a show. On paper they seem silly to me, but you never know till you listen :)
-Ted
Another stupid question: what happens if there is no DAC in the traditional sense but a PCM to PWM transform in a Class D amp, Tact or Panasonic type?Does it need a brickwall filter? I know there are simple 6 or 12db analog output filters between the power transistors and the speaker binding posts.
HowdyHardly anything needs a brickwall filter except a simple non-oversampled Redbook DAC and in particular the digital amps don't need one.
-Ted
Howdy"Could the chief culprit be the 20kHz brickwall filter which makes CD sound edgy? Could it be that upsampling allows to soften the brickwall and make CD sound similar to current hi-rez formats?"
Yep, but in addition I'd say there are other things that can make systems sound edgy. E.g. RFI pollution, ground loops, jitter...
-Ted
HowdyMy experience is that most (if not all) digital processing harms the sound more than it helps it and I prefer Redbook and SACD delivered with no processing in a simple (not necessarily expensive) analog chain. No EQ, no Room correction, no digital crossovers, etc.
I know that there are people who like what they get from digital processing on the PCM signal, but I don't.
-Ted
Why did I spend so much time discussing with you
if you prefer the artificial edginess of a low
rate sampling format over splined waveforms which
at least resemble the original material better?
HowdyA proper Redbook filter (oversampled or not) gives the best possible reconstruction of the original signal (at least after it was sampled.) I prefer SACD to Redbook for the obvious to most reason that it's closer to the original material, but once again this has nothing to do with "splined waveforms" which is at best misguided.
-Ted
I think digital amplification would eliminate the "advantage" I think RBCD has over SACD- Listenability. For I've yet to listen to a digital amplifier that I thought was comparable to a good analog amp in this regard.
Do you mean digital amp with a digital input? I agree that "digital" amps with an analog input cannot compete with good pure analog amps. But if you feed a digital signal to a real digital amp even the most expensive analog gear has a hard time competing.
"But if you feed a digital signal to a real digital amp even the most expensive analog gear has a hard time competing."I guess I'll have to live in disagreement on this one....
Have you actually tried a comparison? For instance a TACT based system fed directly from a transport against a good analog system with an expensive CD player (or transport/DAC), both monitored through good headphones?
"Have you actually tried a comparison?"In fact yes.... A while ago, I had a digital amp and a single-ended pentode amp of comparable price, and I thought the SEP amp obliterated the digital amp. Killed it. Demolished it. When I was listening to the digital amp, it sounded OK at the surface, but I came to the realization that the soul was being ripped out of the music.
What is pleasing to the ear and what is truthful
aren't the same thing. A digital amp connected
digitally to a CD drive will bring you the
brutal clarity and edginess of the RBCD format.
It is quite likely you will not like it, because
RBCD resolution is too low to be warm. Analog
equipment helps soften the edges, or a smart
upsampler.
HowdyA proper reconstruction filter has softened them just the right amount, i.e. back to their original (band limited because of the A/D's antialiasing filter) shape. Any further softening is some form of low pass filtering which is needlessly throwing away freq response.
Don't get me wrong, more resolution is good, but we're stuck with Redbook's resolution for CDs. Also upsampling isn't necessarily evil, it can allow a better implementation of the proper reconstruction filter, but this isn't a softening of the non-upsampled filter implementation.
-Ted
"Analog equipment helps soften the edges, or a smart upsampler."What's a "smart upsampler?" How does it differ from a conventional upsampler?
As I understand it there are good and better upsamplers. The British dCS upsamplers in the kilobuck bracket are probably quite a bit smarter than the pedestrian Behringer SRC. You can tell by feeding a red book signal to the SRC and then compare the original with the 16/44 output of the SRC. The original will be audibly superior. Only when you upsample to 24/96 the SRC will do a decent job.
Which digital amp did you use? Did it have a digital input?
I can upsample RB to DSD as well as play SACD. Basically RB upsampled to DSD sounds very similar to native SACD if no direct comparison is made. When a direct comparison is made between the two media then SACD is superior.As far as RBCD compared to RBCD upsampled to DSD is concerned I have sympathy with those who say leave it as 16/44.1. There is a better sense of "thereness" with RB straight. I leave ny system doing straight RB for months at a time. But eventually I always drift back to DSD upsampling. This is with a diet of mainly classical music where the overall smoothness and grain free nature of DSD upsampling has particular merit.
In regard to upsampling RB to other sampling rates e.g. PCM 176.4 or 192 then the issue is not as clear cut and straight RB could be my preference. BTW, as always the digital interconnects have a large effect upon the result.
My experience in comparing raw 16/44 to 24/96 is as follows: The raw RB often impresses with a fresh, in your face sound. The upsampling renders the sound more mellow, laid back and, IMHO, more natural.Listening to difficult music such as strident strings shows in my view that the freshness of RBCD is an artifact of the low sampling frequency. I would assume that lowering the sampling frequency to 38kHz or less would even increase the "freshness."
I agree, of course, that the raw RB sound, being "fresh" might render certain pop music (eg electropop) more impressive. In some instances, the RBCD might sound even "better" than its twin SACD if played on the same gear.
"My experience in comparing raw 16/44 to 24/96 is as follows: The raw RB often impresses with a fresh, in your face sound. The upsampling renders the sound more mellow, laid back and, IMHO, more natural."I cannot disagree more....
Yes, Pinco I think there is a lot in what you say. In particular your penultimate sentence got me thinking about systems in general. I suspect that lots of gear with a high "PRaT" factor achieve this by having subtle distortion mechanisms which enhance certain music forms. It is interesting that people who prefer, say, classical music will IMHO tend not to own those types of sytem, at least as far as I can judge from inmates systems and from my own experience. BTW, I don't mean that they (me?) prefer the alterantive of dull or leaden systems of course.Some systems play like metronomes - musicians tend not to!
"Some systems play like metronomes - musicians tend not to!"First the precision of digital audio technology and the
rhythmical (im)precision of musicians is on such a completely
different scale, that any comparison is not of any use.The technical reproduction of digital audio should be as
precise as possible, or it will simply be wrong. It certainly
doesn't get funky. There is no funk in jitter, just noise.So if we go past that, I'd like to criticize the second
presumption in that statement. It is an intolerant statement
against most electronic music (hand made excempted) that a
musician should follow his human rhythmic capabilities and
not make a conscious artistic choice to WANT electronic
precision in her music.Especially as I am in the US right now I can see there is a
huge disrespect in the population for the art of electronic
music. That is extremily incorrect to do. A musician is a
hard working artist, no matter if he took ten or twenty takes
to get that guitar riff right, or if he chose to sit in front
of a computer for hours to get that beat exactly as he wants
it. It is an artistic choice in both cases. There is no such
thing as "pre-programmed automatic disco" without soul. But
there may be music done quickly and without care - you can
find that both in electronic or analog music. The truthfulness
of an artist cannot be derived from the artistic choices she
made, but maybe from her attitude and care towards her work.
Oh, by the way, PAR, this is not intended as a criticism against
you but a general manifesto pro the choice of wanting the clarity
of a computer controlled rhythm over the funky messiness of an
asynchronous bunch of people playing in a rock band. In fact both
approaches have their just moments. And a symphony simply cannot
be recorded with computer controlled sync, it would never sound
like one if each musician was to play after the other.I'm just currently disturbed by this intolerance which reminds me
of "disco sucks" in 1979. Disco music back then was considered
unnatural compared to hand-made rock'n'roll. So ridiculous, since
today everybody knows that the vast majority of disco music was
handmade and only pioneers like Giorgio Moroder were (in part)
using electronically controlled rhythm for disco music. So if you
think of what the "disco sucks" revolt was trying to achieve, they
later got the full slashback with techno and dancefloor eurotrash. ;)Further materials:
http://en.wikipedia.org/wiki/Disco_Demolition_Night
http://www.mrcranky.com/movies/lastdaysofdisco/6.html
http://www.jahsonic.com/DiscoSucks.html
My point alluded to the my perception that some reproduction equipment imposes a false sense of rhythm. That is the music loses part of the freedom inherent in the natural ebb and flow of the performance. Of course my presumption here is that the recording is of musicians reacting to each other in real time and space. Pop recordings mainly from the last couple of decades of the last century onwards do not necessarily adhere to this paradigm as musicians work to a click track and are not even necessarily in the same space or day/week/month as each other.Your points about electronic music are taken but are not really wholly germane to what I was saying, after all a recording that is fixed by an electronically derived and therefore unyielding beat should sound that way whatever it is played upon. If that is what was intended by the music's creators then that is fine by me. My point was anti equipment that fails to reveal more subtle rhythmic variations where they exist (for the appropriate form of music - i.e not electronica to respect your point) and where some of the "soul" of the performance resides.
If reproduction equipment fails to faithfully reproduce the rhythm and subtleties of timing of music it could only be vinyl record or audio cassette gear. Digital equipment will faithfully follow the clock.
HowdyNot quite. Since the input is filtered in digital the artifacts of that filtering and or the reconstruction filter might be adding or detracting timing clues. Heck almost any filtering changes the phase of some freqs compared to others and softens impulses. In so far as impulses (think percussion) convey timing, filtering messes with timing.
-Ted
Yes, phasing, granted, but we are talking about
time frames that have nothing to do with human
sense of rhythm. No way. Even a vinyl or tape
would only mess with the rhythm of the music
when it's motor or transport is damaged.I can tell you guys are technicians, not musicians!
HowdyBoy we can tell you don't play instruments, sing, etc. and have much experience with various digital devices, otherwise your sense of timing would feel the same thing.
-Ted
Boy you'd feel so embarrassed, were you at my live
show in NYC while you were posting stupidities here.
Embarrassed to even think something like that, while
the energy and ultimate tap effect (= dancing)
of synth disco electro music hits your ears. ;-)
I don't see a digital input filter if we have a digital recording straight to CD master. A low pass D/A output filter, yes. But what about analog audio? How many filters have to be passed by the signal until it arrives at the speaker's diaphragms?
HowdyThe filters I was talking about aren't necessarily digital filters, they are the (required) antialiasing filter in the A-D and the reconstruction filter in the D-A. These filters are almost always much higher order than the analog filters you are talking about and almost uniformly have worse phase response.
Besides have you ever noticed that some discs make you want to tap your toes more than others? Want to guess which had more processing done? :)
-Ted
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