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Oversampling

 

swampcat
Unregistered guest
Looking for new cd player. almost all cd players are rated 8 times oversampling. ONKYO rates theirs 128 times? Other than the 128 oversample rating the onkyo has terrible specs compared to denon (best specs) yamaha, HK, I have a feeling this is just overkill(128 oversampling) or some advertising gimic . My personal feeling ,is that the ,signal to noise ratio, dynamic range, 20 bit burr brown procesers ,frequency range,HDCD capable, and THD are more important. Does anyone know why onkyo's oversampling would be so different then all others? How much does oversampling matter,if at ,once you reach a certian number? I'm leaning toward the denon top model.
 

Silver Member
Username: John_a

Post Number: 932
Registered: Dec-03
It is all numbers. The first CD players had no over-sampling, just read at 16 bit, like the format. Later Sony etc. came in with one-bit, (bitstream) making oversampling essential.

They are all completely blown off the map by DVD-Audio. On two channel, you get true 24 bit, and 192 kHz sampling frequency (compare to 16 bit, 44 kHz for CD). HDCD is nowhere to be seen.

I started the thread here Twilight of the Compact Disc. No-one should buy a CD-only player today, imho
 

swampcat
Unregistered guest
A dvd-audio player would make a better cd player , even if i used it for stereo purpose only. Really not into movies that much. Have no interest in surround sound at all. Just a two channel guy. (Still love my turntable). Original onkyo Integra broke after 18 years. Replaced with a sony last year, wich is terrible. Hey thanks alot for the info.
 

tt
Unregistered guest
The thermal noise floor of analog equipment is roughly 19 bit, max 20 bit resolution. Ever wonder what that background noise is coming from the speakers when you crank up the AMP/receiver without any music playing? It's there because we don't live at absolute 0 temperature. This is the physical limit of all equipment and cannot be practically altered. Going beyond that will not improve anything, and the little minute details you strive to preserve will just be drowned out by that noise. Just like anything, what you put in is what you get out. Good recordings by meticulous engineers will give you the best sound, no matter what the format. Finely recorded CDs will sound much better than crappy DVD-A or SACD. If you already have a good CDP, just stick with it and save your money or some nice CDs.
 

Silver Member
Username: John_a

Post Number: 947
Registered: Dec-03
swampcat,

I agree. DVD-A has made me go back and listen more carefully to my LPs. I still love my turntable, too, more as the years go by!

tt,

Broadly I agree. I don't quite see how you can put a sample size in bits on analogue; it is only an analogy, anyway, a bit is a binary unit of information, only applicable to digital encoding.

The noise in analogue can have different sources. Most can be eliminated for all practical purposes. It is not usually temperature-dependent!

But I agree, in the end, we are all in the hands of recording and sound engineers. The DVD-As I have suggest that they are still making the same old mistakes, and there is now watermarking etc. to add to the list.
 

2muchmujik
Unregistered guest
Oversampling in the context of the D-A process involves multiplying the sampling frequency by a whole number, typically between 4 and 32, or even higher. For example, in '8x oversampling', CD's base rate of 44.1kHz is raised to 352.8kHz by introducing seven new 'empty' samples between the original data samples. These new samples, though, are often not just empty strings of noughts, but based on mathematical models to assist the DAC to work more linearly with the extracted data.

Oversampling, as well as easing the workload of the anti-aliasing filter, which can now operate more gently at a higher frequency, can also reduce distortion created when those analogue signals are first turned from continuous, analogue waveforms into stepped, digital, stair-like curves. This quantization noise is now spread over a larger band after oversampling, and can even be somewhat shifted out of the audible envelope by the technique of noise-shaping.
 

Silver Member
Username: Two_cents

Post Number: 242
Registered: Feb-04
Just want to offer a different opinion from swampcat, who states: "A dvd-audio player would make a better cd player , even if i used it for stereo purpose only." IMO a good cd player (e.g. the NAD players are a good budget reference) will play cds better than comparably priced dvd-a players. The cd player will generally have better DACs, transports, power supply, and build quality than a comparably priced dvd-a player, since none of the cost goes into the video and dvd-a sections of the player. More importantly, the proof is in the listening.
 

Gold Member
Username: John_a

Post Number: 1502
Registered: Dec-03
2muchmujik,

That is great, thanks. So it is not simple interpolation, as I thought.

2c,

I agree, too. but not so many consumers can make the comparison before purchase. We all mostly just have one of something. Since we mostly have CD-only players already, it seems to me to make sense to go for DVD-A (and/or SACD), then make the comparison. The we might worry whether the new CD performance could be better. But the step up to DVD-A is huge, incomparison, surely?
 

Silver Member
Username: Rick_b

New york Usa

Post Number: 296
Registered: Dec-03
To All,

Hopefully for the last time let me state: A combo DVD player will never outperform a dedicated high end cd player or transport. I have a California Audio Labs CL20, and a CA Azur 540D, and there is no comparison on red book cd's. A $400 unit can't compete with a $2500 one.
 

Silver Member
Username: Two_cents

Post Number: 243
Registered: Feb-04
John A.,

We are in perfect agreement regarding the superior sound of DVD-A (and SACD in my opinion) over redbook CD.
 

Gold Member
Username: John_a

Post Number: 1506
Registered: Dec-03
Two Cents,

Yes, that is my point exactly. And the superiority is such that you may as well just keep your existing CD player, whatever it is. Unless you have an awful lot of money. No-one discusses the resolution and hi-fi credentials of MP3 players. You can probably tweak them a bit with over-sampling and different forms of compression, but what's the point?

Rick,

"will never" is difficult to justify. "Has not, yet...." might find general agreement. And, again, it is not the price that does it. Prices drop, and technical standards rise, given enough time. The first CD players were awful and cost about $1000; the cheapest CD player today is probably much better. It is still worth looking for the best sound for the money.
 

Silver Member
Username: Rick_b

New york Usa

Post Number: 299
Registered: Dec-03
JohnA.,

Your point is well taken. You are right about price. You can get some high priced junk, but usually the higher price should mean better components(DACS-transport etc.)and build quality. I agree on the best sound for the money.

The thread was starting to sound that there is no longer a need for for a dedicated player.
 

Gold Member
Username: John_a

Post Number: 1508
Registered: Dec-03
Thank you, Rick.

That is a most succint summary of my opinion, too, on this whole question.

Any one who has not, please see my attempt to spread the news by following the link in my post, above, of May 09.

That post did not elicit the criticism I expected.

It seems to me that oversampling is only an issue when the sampling frequency of the original programme material leaves something to be desired.

There would be absolutely no point in oversampling most DVD-Audio recordings, I think.
 

Silver Member
Username: Rick_b

New york Usa

Post Number: 301
Registered: Dec-03
Thank you John......


P.S. What can you share on Quad/Spendor monitors?
Please go to SPEAKERS.
 

Gold Member
Username: John_a

Post Number: 1513
Registered: Dec-03
Rick,

My pleasure. Both have an excellent reputation. Spendor was one of the select group of BBC LS3/5a makers: neutral, simple, well-made, reference quality studio monitor-type speakers. Quad was once a legend, especially the electrostatic speakers and electronics. Quad is now under new ownership, but exploiting "retro" styling; I do not know what effect that has had on the product itself. Jan V would be the guy to know, and maybe comment.
 

Unregistered guest
Attached link addresses oversampling and upsampling in detail. To his credit, Zmuchmujik,
just might be the ghost author:
http://www.simaudio.com/upsampling.htm

Those so inclined may find it of interest.
 

Gold Member
Username: John_a

Post Number: 1540
Registered: Dec-03
JW,

Excellent link. Thanks.
 

Bronze Member
Username: Seamus

Post Number: 28
Registered: Feb-04
OK guys, here's the oft-discussed question once again.
Rick talks about high-end dedicated CD players. What about equivalent (low) priced CD players vs DVD (combo/universal) players for redbook reproduction ? For e.g., how much, if at all, superior is a low-priced CD player like the NAD C521 BEE compared to a similar low-priced DVD player like the Pioneer DV-565 ?
 

Silver Member
Username: Rick_b

New york Usa

Post Number: 308
Registered: Dec-03
Seamus,

Let's take 2 $500 units, a dedicated cd player, the other a combo dvd player. I still say you have to give the sonic edge to the cd player for redbook cd. It only makes sense, because the dvd player is a compromise to do a lot of things well. The dedicated player has to do only what it was designed to do.

 

J. Vigne
Unregistered guest
I would say it's hard to generalize about similarly priced products anymore. It's true that the more things added to any unit at an equivalent price are more than likely taking away from another part of the whole. And performance is most likely the first item to be replaced when the bean counters are given a choice.
But the way components are made today is different than even 10 years ago. The mass market manufacturers have been making more or less the same product and dressing it up with features while the performance items remain pretty much the same. From $150 to about $500 you are mostly buying features and no added performance. From $500 to about $900 there is a similar situation.
On the other hand, as has been discussed on another thread, some manufacturers will bring a performance feature out in what is to be a mass market model in hopes of lowering the cost of a laser, transport, IC chip or what have you. This can make some inexpensive products compare more favorably with another player at 1/3 more money.
The easiest way to find the best player is to find a dealer(s) who will allow you to listen with your own CD's for awhile and tell you what they know about the internal workings of the players they sell. If the best answer they can give is, "It's on the other shelf" or "Oh yeah, that one's way better", you should look elsewhere for your purchase.
 

J. Vigne
Unregistered guest
Additonally, I am unaware of any chip set that can do 128 time oversampling on just CD. This may be accomplished by cascading several IC's together which, in my opinion, is not good audio practice. The Japanese manufacturers have a gift for what used to be called the JVC factor. This allows them to dicover a wonderful new circuit that they have employed this year to make their product better. This circuit is given a wonderful name and acronym: the Absolutely Wonderful For Uniformally Little circuit, or as the literature describes it and the front panel displays in gold leaf A.W.F.U.L., and by next year it seems they have forgotten how good this circuit is and have found another new circuit that makes their product the best it has ever been. I believe I would do a little more investigation.
 

JW
Unregistered guest
...priceless.
 

Gold Member
Username: John_a

Post Number: 1563
Registered: Dec-03
I agree, JW.

J.V., I do not think you require any more investigation, as suggested by what is surely a typing error in the last sentence. Much less Orwellian.

A perfect and very large example of Japanese corporate amnesia is Sony's "The Compact Disc. Perfect Sound that last Forever". Or was that Philips? I forget.
 

Unregistered guest
...Really does become confusing; perhaps, it was the behemoth Sansui Coporation.
 

Gold Member
Username: John_a

Post Number: 1572
Registered: Dec-03
Philips certainly ran a very a big advertising campaign with that slogan for the new format, and I think Sony did, too; advertising hordings, full-pages in newspapers, etc., with a pretty female hand holding up one of the miraculous new discs, reflecting and diffracting light to give a rainbow effect. As I have said on this forum, several times, plugging SACD as an improvement over CD is bad enough, but one could perhaps give them the benefit of the doubt. However, using analogue master tapes as the source, to improve on the CD releases, amounts to saying "Do not believe us: we lie".
 

Unregistered guest
JA,
Yes, you're right on everything - past, present, assessment wise and probably DVD-A; although, formats are changing so fast (blue laser?) who knows? New format = new hardware, as you already know, and they're in the business of selling new equipment - who isn't.

Was kidding on the "behemoth" Sansui comment; I always wonder what happened to Sansui, as I fondly recall their old stereo equipment. Kind of a cute name, like something you'd pick up with chopsticks.

Pass me some of that sansui, will ya' please?
 

Gold Member
Username: John_a

Post Number: 1576
Registered: Dec-03
JW,

Thanks!

"Sansui. Floats like a butterfly, stings like a bee."

No originality, some people... Very memorable, though.
 

Unregistered guest
All,
With due respect to swampcat, the Onkyo dxc390 IS purported to have 128x oversampling and 192/24 DAC's. It als weighs a gutsy 15 lbs., aluminum faceplate, etc.

Anyone care to explain these specs?
http://www.vanns.com/shop/servlet/item/features/534199305
 

paul1980
Unregistered guest
I am going to buy a DVD player to replace an old (and broken) CD player. I have many CDs and am I not interested in the near future to the new and spectacular DVD-A or SACD. My interest is to improve the sound quality at a reasonable price. New cheap DVD players offer 192KHz/24 bit DAC (terrific!), but it is not clear to me if they use (eg the sony DVP-NS585P) the oversampling benefits, i.e. from the original 44.1KHz/16 bits through a digital filter section before the analogue output filtering. Is the digital output at 192KHz/24 bits also playing CD? Could somebody discuss the CD quality restituted by DVD players as compared to CD players? Thanks
 

Gold Member
Username: John_a

Post Number: 1964
Registered: Dec-03
Paul, see my link posted here on May 09, above. It links to a thread that puts the case for DVD-A. You can certainly get DVD players that play CDs very well. The benefits of over-sampling are probably small; there is only so much resolution you can get out of 44 kHz, 16 bit, whatever you do. DVD-A is a big step up in sound quality.
 

J. Vigne
Unregistered guest
Paul - This post is brought over from another tread where the question of up sampling standard 16 bit format CD's was presented:

I have not had personal experience with the latest goings on in digital and I easily admit the perturbations of digital have left me in the dark. I read the descriptions of what is being done and I want to go read my tube substitution tables. I mean, why did we go forward after the 12AX7 was designed? New digital makes my eyes water. I can understand how DSD works, somewhat, and that the basis for one bit technology can be interpolated into an oversampling of the original 16 bit information. But ... one of the early complaints about digital (particularly CD) was the 16 bit format of Compact Disc was never truly achieved as the mechanism of things such as "the least significant bit" and dither meant that the real resolution capability of 16 bit/44.1kHz sampling as the CD standard meant that by playback you were actually down to no more than 14 bits and sometimes could go as low as 12 bit resolution. I've not seen anyone address how that has changed in the past 20 + years. So unless I've missed something very important, which is possible because I do get lost in the explanations now days, I'm having a very hard time understanding how upsampling to tremendous levels at any point in the loop can do much with what is, for all intents and purposes, a medium resolution format. The comparison to an Atari 400 was made more than once in the digital vs. anaolg wars.

That said there have been increases in the technology of CD such as better lasers, better transports (?), and just better parts all around at the higher price ranges. But that has no real effect on the purely digital side of playback. Maybe someone who keeps up with digital can do a good job of explaining.
I also have suspicions about the industry's intentions here. SACD and DVD-A have not taken off the way anyone would have hoped and both are in danger of being superceded by more contemporaray technology. So here is a music industry and audio industry that has promoted (licensing and format battles aside) technologies that displace the perfect sound forever format. When the improved technology doesn't seem to be of interest to a society that is more interested in convenience than performance*, the perfect sound forever is then promoted as better than perfect sound and possibly better then what is better than perfect sound. Maybe I've just been laying out here in the sun too long, doing my job, watching for bad guys and scratchin' and lickin' some parts when necessary, but I feel somebody yanking on my chain.

*As I read it, several of the driving forces behind advances in CD playback technology is entirely based on percieved improvements in playback within your automobile. Audiophiles now exist in traffic but not leisure. 70 MPH or bust!
 

Gold Member
Username: John_a

Post Number: 1966
Registered: Dec-03
"Upsampling" is the title of this thread, but there is a more general issue.

Consider an analogy with photography. CD is like a standard for digital photography which was announced as better than 35 mm emulsion film, but wasn't. Nevertheless, CD took over, largely for convenience. Upsampling seems to me to be a bit like interlacing or image reconstruction (someone please say if this is wrong); it smooths out the pixels, but the shortest distance between two resolved points, on a photo, cannot be decreased further, because that would require information that is just not there in the photograph. So upsampling may have some preceived benefit, but it is not improved resolution.

Now, twenty years or so on, we have higher resolution, for audio, than CD. That is a good thing, and it is a wonder it took so long. Certainly the convenience of copying, perfectly, and editing and transferring files, gives digital audio and digital photography many advantages. In both cases, the resolution of digital can increase to the point where it is indistinguishable from analogue.

In the case of audio, the real question, imho, is whether or not we have got there, yet. With the highest resolution of DVD-A (24 bit, 192 kHz PCM), we could only really tell if we had a higher resolution with which to compare.

It should not be difficult for someone with a computer and the right ADCs to record in, say 32 bit, 384 kHz PCM. Then one could see if anyone could tell the difference between that played back straight, and a playback downsampled to 24 bit, 192 kHz.

Surely someone has tried this......?

BTW blue laser etc. does not change anything, except how much you can get on one physical, optical disc. Playing time is what you are used to. LP was a more successful medium than CD, and was only OK up to about 20-30 minutes per side.
 

Gold Member
Username: John_a

Post Number: 1967
Registered: Dec-03
Sorry "oversampling". I suppose it is more like signal averaging. But it is still better to have the resolution there, in the source. One could oversample 32/384, and try that, too.
 

Silver Member
Username: Goldenarrow

Post Number: 121
Registered: Jun-04
JW,

Thanks for the web link to the simaudio article on upsampling. I have been looking for a cheap way to get my existing CD's to sound better. I don't want to buy a $1000 CD and DAC combo but I don't want to get into snakeoil territory either. The simaudio article seems like it puts more emphasis on oversampling than on upsampling. One thing they do not talk about is how one could, using complex mathematics, change the waveform to make it sound better. To a purist, that would be disgusting, but I am more of a pragmatist than a purist (as soon as you get away from live performance, you can do whatever you want to the source material, IMO).

I don't think simaudio answered my need but it is an interesting article nonetheless.

:-)
 

Silver Member
Username: Goldenarrow

Post Number: 122
Registered: Jun-04
John A.,

I don't know if it is possible, but I read somewhereelse that one could upsample to a higher degree than needed, then downsample to a high-rez rate and end up with a wider dynamic range, lower noise floor, and smoother sound. Don't know if it is true, it would be nice to get this verified somehow!

:-)
 

J. Vigne
Unregistered guest
I just checked with the nuns and their info is upsampling to create more information than you started with is akin to the parable of the fishes and the loaves. Disbelieve at your own peril.
 

Gold Member
Username: John_a

Post Number: 1969
Registered: Dec-03
goldenarrow and J. Vigne,

Peace! I would hate to see diagreement. I work from basic principles, and think you are BOTH correct, since you are talking about two different things.

goldenarrow refers to wider dynamic range, lower noise floor. I think I can see how over- or upsampling (is there a difference?), like signal averaging, can increase signal-to-noise ratio. The signal is added to that from other samples; the noise isn't. If I am right, then there is a law of diminishing returns, and the S/N ratio goes up with the square root of the number of samples you average. You could take that, and write at a higher resolution than the individual samples, and reduce the noise.

But that is not resolution. So Jan is also correct. Out of all that averaging or oversampling, you cannot resolve things that were not there in the first place. You just get less noise obscuring things that were there. Following jan's obession, the Turin shroud comes to mind, for some reason.

So you still need the highest possible resolution, in my opinion. CD wil never faithfully reproduce things happening faster than half of 44 kHz, 22 kHz, and that is about 50 microseconds. That need not be just frequency of sound, or pitch. I would not mind betting that the ear can hear transients much faster than that, and, for example, a bow hitting a violin string is full of complex information at greater than those sorts of speeds, information our brains use to identify the sound as coming from a violin, and not something else. That is an example of "resolution" of the kind that is either there or not, and no amount of smoke and mirrors can get it back if it was lost in the recording or at any other stage.
 

Silver Member
Username: Goldenarrow

Post Number: 126
Registered: Jun-04
.........Y E P............
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