24 bit CD Transports

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Mo
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#1 24 bit CD Transports

Post by Mo »

Hey Gang,

I'm just curious as to 24 bit playback on a CD player.

Would a CD transport be able to playback 24 bit if it had an external 24 bit DAC?
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Nick
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#2

Post by Nick »

Not if its playing a CD, as that only has 16 bit data.
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Mike H
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#3

Post by Mike H »

Would that be by "over sampling" then? Or, was that replaced with something else Image
 
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Mo
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#4

Post by Mo »

Nick wrote:Not if its playing a CD, as that only has 16 bit data.
Aah ok, so the actual disc can only store 16 bit?
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Ali Tait
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#5

Post by Ali Tait »

Yes,as far as I know,which isn't far! Lots of DACS claim to upsample,though many say that creates as many problems as it solves from what I've read.
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#6

Post by cressy »

i got a better sound out of a 16 bit (or was it 14?) meridian mcd than i did wih an xray that upsamples to 24 96. probably because the sadly departed mcd matched my system better. the x ray to me came across very clinical, the mcd had 'verve', i.e it got the foot tapping. for me, i dont really care what technology it has under the bonnet, but how it puts the music across. mcd was coloured. but gloriously so! id say try a cheap golden oldie first before shelling out a lot of pennies for the upsampling hdcd, sacd, high bitrate stuff. might be surprised
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Mike H
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#7

Post by Mike H »

Can't remember what the point of up-sampling was, unless merely to produce smaller V-change steps between each sample point. (?)
 
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The Stratmangler
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#8

Post by The Stratmangler »

HDCD - the crafty art of getting more than 16 bits into a word length, yet doing it in such a way that if the additional data can't be read/converted it is ignored.

Curiously enough I have been playing with dB Poweramp today (trial version) and have managed to extract the extra bits for playing using Squeezebox.

More later.......

Chris :)
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The Stratmangler
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#9

Post by The Stratmangler »

And the outcome of the CD/HDCD flac rip testing is that..........




HDCD comes out better than CD.
But it is only very subtly better.

And probably not worth worrying about.

So much ado about very little really.

Chris 8)
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#10

Post by Mike H »

Coincidentally I'm just listening to the BBC local radio from orft the webernet, ("Late night big band, jazz and irresistible sounds", it sez 'ere) you saying that reminded me to double-check the BBC iPlayer bit stream speed, yup 44.1kbps, same as the CD sampling rate! Image


Yee-hah...

For no reason in particular
 
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#11

Post by Nick »

Mike H wrote:Coincidentally I'm just listening to the BBC local radio from orft the webernet, ("Late night big band, jazz and irresistible sounds", it sez 'ere) you saying that reminded me to double-check the BBC iPlayer bit stream speed, yup 44.1kbps, same as the CD sampling rate! Image


Yee-hah...

For no reason in particular
XCept (and sorry to be a pedant), the bit rate of PCM CD is 1.4 Mb/sec (and a bit). Its sample rate is 44.1 thousand times a second, but each of those samples involve two channels of 16 bit depth.
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#12

Post by Mike H »

Oh yeah I got it back to front
 
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#13

Post by Neal »

Upsampling is a sample rate conversion IE: 44.1 to 88.2 etc. It uses interpolation to guess or fill in the new data. Oversampling is very similar and typically used in the DA process to provide a more accurate or linear output from the 16bits available IE: x4 oversampling results in a sample rate of 176.4Khz....it also allows for the anti-aliasing filter to be moved well away from the audio band.
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#14

Post by The Stratmangler »

Had a bit more time to compare the HDCD rips to the standard CD rips, and the most important differences I have noticed are that the HDCD rips have more body to the sound, and better placement of instruments in the stereo soundfield.

The other thing is that the HDCD rips are -6dB down in level compared to the CD rips. I've compensated for that by doubling the level of the HDCD rips using an audio editing tool.

None of the tracks hit 0dB digital distortion (nor did the CD rips either).

It's odd though getting 24 bit rips at 44.1 kHz from a CD. I believe that the HDCD encoding adds 4 bits into the data, and the entire shebang has another 4 redundant bits added during the rip process.

If anyone else fancies having a play then you'll needed to go to http://www.dbpoweramp.com/ and download the ripping tool & the DSP effects.

Chris :)
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#15

Post by docfoster »

I've noticed that of the players I've tried, BDP sound better through my DAC (Musical Fidelity A3 24 192k upsampler) than do CDPs via (all via coax digi outputs).
Has anyone else noticed this? Are Bluray transports in some way generally superior? Or are these perceived differences purely coincidental in my case?
Ben
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