CD vs. Hi-Res

[Pat D]

Audibility of a CD-Standard A/D/A Loop Inserted into High-Resolution Audio Playback by E. Brad Meyer, J. Audio Eng. Soc., Vol. 55, No. 9, 2007 September.

It's a good read.

http://aes.org/tmpFiles/JAES/20070924/JAES_V55_9_PG775hirez.pdf

 

[davidtwotrees]

I wasn't totally clear on what they were trying to accomplish. For much of the paper I thought they were saying that cd sound was equal to sacd/dvda. I guess they were saying that cd sound was equal to hi res that is dumbed down to 44.1? At they end they were clear on this much---
"Though our tests failed to substantiate the claimed advantages
of high-resolution encoding for two-channel audio,
one trend became obvious very quickly and held up
throughout our testing: virtually all of the SACD and
DVD-A recordings sounded better than most CDs—
sometimes much better. Had we not “degraded” the sound
to CD quality and blind-tested for audible differences, we
would have been tempted to ascribe this sonic superiority
to the recording processes used to make them."

Good read. Thanks for the heads up.

 

[MDS]

They were trying to show that 16/44.1 is a sufficient bit depth and sampling rate and that even using high resolution masters it would not degrade the sound.

From the block diagram they are going A/D/A so using a high-res SACD/DVD-A as the 'master' and then converting it to analog, resampling the analog signal at 16/44.1 on the fly, then converting back to analog for playback resulted in no discernable difference from an original CD of the same material that was sampled at 16/44.1.

 

[mtrycrafts]

From the block diagram they are going A/D/A so using a high-res SACD/DVD-A as the 'master' and then converting it to analog, resampling the analog signal at 16/44.1 on the fly, then converting back to analog for playback resulted in no discernable difference from an original CD of the same material that was sampled at 16/44.1.

They compared two analog sound one hires and the same hires bottled necked to the 44.1/16 rate with no difference. Is this what you said? I get confused at times

 

[mtrycrafts]

... For much of the paper I thought they were saying that cd sound was equal to sacd/dvda. .

Yes, you understand that part correctly
They compared the hi res and a dumbed down to 44.1/16.

 

[MDS]

Yes, but if you read carefully they are trying to 'prove' that 16/44.1 is sufficient to fully capture the original analog signal. In their test they do that by taking a high-res master that was captured at a higher bit depth/sampling rate and then resample it at 16/44.1 under the theory that if the original high bit depth/sampling rate were truly superior, resampling that signal at a lower bit depth/sampling rate would clearly show differences. It did not.

They do however add the caveat that an original analog signal sampled at a higher bit rate/sampling frequency could very well sound better when played back at the same bit depth/sampling frequency.

I think the intent was to show that 16/44.1 is sufficient to fully capture the original original analog recording and their tests show that even if the original was sampled at a higher rate, it adds nothing if that original is converted to analog and then resampled at 16/44.1. In other words, they believe 16/44.1 is sufficient to fully capture the original analog signal.

 

[Joe Schmoe]

CDs sound so perfect to me that, while it might be possible to improve on the measured performance, I cannot imagine the result sounding better.

 

[mfabien]

Frankly, in 2 channel analog stereo, HDCD, SACD and DVD-A are not a great improvements over CD, IMO.

SACD is great when in surround. DVD-A in surround (universal player), matches DTS surround (normal player) and both are very good. So are DTS music discs. But audio mixing is key. Good examples of good mixing:

- Steely Dan's "Everything Must Go" DVD-A disc.
- Cirque du Soleil's The Beatles "Love Event" DVD-A
- "Hell Freezes Over" by the Eagles DTS Music disc.

Of course, all of the above in analog output.

 

[3db]

Still confused

Yes, but if you read carefully they are trying to 'prove' that 16/44.1 is sufficient to fully capture the original analog signal. In their test they do that by taking a high-res master that was captured at a higher bit depth/sampling rate and then resample it at 16/44.1 under the theory that if the original high bit depth/sampling rate were truly superior, resampling that signal at a lower bit depth/sampling rate would clearly show differences. It did not.

They do however add the caveat that an original analog signal sampled at a higher bit rate/sampling frequency could very well sound better when played back at the same bit depth/sampling frequency.

I think the intent was to show that 16/44.1 is sufficient to fully capture the original original analog recording and their tests show that even if the original was sampled at a higher rate, it adds nothing if that original is converted to analog and then resampled at 16/44.1. In other words, they believe 16/44.1 is sufficient to fully capture the original analog signal.

So if sampling at 16/44.1 is sufficient enough to capture an analog signal, why then would an original analog signal sampled at a higher bit rate/sampling frequency could very well sound better when played back at the same bit depth/sampling frequency?

Where does that fit into the equation?

 

[AcuDefTechGuy]

Yeah, I've listened to SACD, DVD-Audio, & DTS-CD, and I don't hear any SIGNIFICANT improvement over a high quality CD. Sure, I like the fact that they used all the speakers. But in the end, high quality plain old 2-ch CD still sounds the best to me. That is why SACD, DVD-Audio, and DTS-CD have failed IMO. The difference here is not the same as going from Dolby Digital to Dolby TrueHD 5.1 & Uncompressed PCM 5.1.

 

[Joe Schmoe]

So if sampling at 16/44.1 is sufficient enough to capture an analog signal, why then would an original analog signal sampled at a higher bit rate/sampling frequency could very well sound better when played back at the same bit depth/sampling frequency?

Where does that fit into the equation?

Again, this could be a purely technical improvement, but not likely an audible one. The resolution of the standard CD already surpasses that of the human ear by a pretty wide margin.

 

[mtrycrafts]

... In their test they do that by taking a high-res master that was captured at a higher bit depth/sampling rate and then resample it at 16/44.1
.

Yes, but what did they compare the re-sampled 16/44.1 signal to? They compared it to the hi res signal. So, they didn't find audible difference between the hi res and CD res. What am I missing?

 

[mtrycrafts]

So if sampling at 16/44.1 is sufficient enough to capture an analog signal, why then would an original analog signal sampled at a higher bit rate/sampling frequency could very well sound better when played back at the same bit depth/sampling frequency?

Where does that fit into the equation?

The way I see the block and the paper is that they compared the hi res to a down-converted CD res of the same music. They had to. No audible differences found.

The quote from the paper that was posted shows that just comparing a hi res format to a 'supposed' copy at the CD res is unreliable. Of course. Who knows how different they may be and this test shows they should not be audibly different, yet they are and is due to a different CD track, not that the CD res is inadequate. That is my take on it.

 

[astrodon]

Yeah, I've listened to SACD, DVD-Audio, & DTS-CD, and I don't hear any SIGNIFICANT improvement over a high quality CD. Sure, I like the fact that they used all the speakers. But in the end, high quality plain old 2-ch CD still sounds the best to me. That is why SACD, DVD-Audio, and DTS-CD have failed IMO. The difference here is not the same as going from Dolby Digital to Dolby TrueHD 5.1 & Uncompressed PCM 5.1.

I have had a different experience when carrying out comparisons. I have compared the Carly Simon "No Secrets" album through the same receiver in LP, CD, and DVD-A format (with the CD and DVD-A on the same player) and the DVD-A sounds far "richer" (for lack of a better word) than the CD and LP, including playing the DVD-A in stereo format only.

 

[davidtwotrees]

I have to agree with the above post. My DVDA's just have a hotter sound than my two channel music discs.

 

[Geno]

I'll add my ditto to that comment. I have a number of recordings on LP, CD, and Multi-Channel SACD or DVD-A (e.g. Donald Fagan's "The Nightfly"). The multichannel recordings are hands down the winners, IMHO. Once you've heard a good multi-channel, the other formats just don't compare.

 

[mtrycrafts]

I have to agree with the above post. My DVDA's just have a hotter sound than my two channel music discs.

Firstly, you comparing 2 ch against multi channel?

 

[mtrycrafts]

I'll add my ditto to that comment. I have a number of recordings on LP, CD, and Multi-Channel SACD or DVD-A (e.g. Donald Fagan's "The Nightfly"). The multichannel recordings are hands down the winners, IMHO. Once you've heard a good multi-channel, the other formats just don't compare.

Yes, of course That is why they came out with multi channel in music as well as movies.

 

[davidtwotrees]

Firstly, you comparing 2 ch against multi channel?

Yep. Which is why the article seemed ambiguous to me. Was it cd vs hires? Well yes but hires that was bottlenecked to 44.1..........so they weren't comparing things I can buy, but different recording techniques......in which case the article doesn't concern me, the end user. What do you have that I can put my grubby little mitts on, today? Which is why I quoted the one paragraph in the article that the author's spoke to me, an end user.

After hearing hires multichannel it is hard to listen to a lot of two channel...and I'm not into scratchy records anymore.....

 

[astrodon]

Though I did point out that the DVD-A sounded better in 2-channel format too as compared to the LP and CD. The "No Secrets" DVD-A has a hi-res 2-channel track as well as a hi-res multi-channel track.