upsampling

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upsampling

Postby conspicuous » Mon Aug 09, 2010 8:49 pm

i have a cayin cdt-15a cd player. For months i played it with the upsampling on (96khz, 24bit). I thought this would sound optimal and as i listened i thought the sound was pretty good. Then recently i turned it off and discovered that the soundstage could be huge and rock steady. For some reason when i switched the upsampling on again the instruments and sounds would move around slightly and unsteadily. I only noticed after prolonged listening with the upsampling on or off. :^)

Now i prefer to listen to my cayin with the upsampler off and i'm enjoying CDs again. :)

Anyone have similar experience with their cd players? Maybe the upsampler in my player is an older generation or lower spec'd? Maybe simpler is better? :^)
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Re: upsampling

Postby JoeyGS » Mon Aug 09, 2010 8:56 pm

I have not heard a cd player as analogue sounding as my non-oversampling diy CDROM player with a tubed output. I have heard the cayin 17t but I still prefer my CDROM player. Maybe the non-oversampling is key?
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Re: upsampling

Postby Tjaderman » Mon Aug 09, 2010 9:06 pm

I had the same experience with my olp Phillips player! I noticed when upsampling is on, sound a bit compressed :^) , as if i lowered the volume by a notch or two! I prefer it off and stayed away from that button!!! :lol:
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Upsampling and Oversampling

Postby Squirrelnutzipper » Mon Aug 09, 2010 9:07 pm

Upsampling and oversampling are two different, but similar methods to increase the sample rate. The question of change in sound for the better or worse in upsampling is highly dependent on the algotithms used to add the "missing " pieces. There is a fair amount of debate on the subject. My preference is for using neither. I like the sound of the old dac chips, like TDA1541A, implemented NOS. Just my preference, though.
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Re: upsampling

Postby rtsyrtsy » Tue Aug 10, 2010 9:36 am

The last time I bought digital gear with serious auditions was 2003 so take what I say with buckets of salt especially since digital develops rather quickly.

From experience, upsampling, non-oversampling, and oversampling can all sound good and bad, depending on implementation. This suggests, at least to me, that there are other more important factors like:

-a clean power supply: I definitely prefer my Red Wine Audio Squeezebox on batteries than on the A/C wall outlet.
-nature and quality of the output stage: I've generally had positive experiences with tubed outputs.Which doesn't mean that S/S output stages can't sound good (case in point, Naim). I've also had good results from upgrading caps.
-are you listening to the contents of the CD as the producer intended or your CD player's error correction algorithm? I would attribute to this factor why I used black pens and CD cleaners a practice which later on evolved into read until right rips of my CDs.

The great thing about your situation is that you can have it both ways with the switch of a button. There are some recordings (in my experience, the better ones) that benefit from a minimalist, non-oversampling treatment. There are others that benefit from the smoothing and "extension" that I hear from upsampling.

So keep enjoying!
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Re: upsampling

Postby conspicuous » Tue Aug 10, 2010 7:40 pm

gents, thanks a lot for sharing your inputs. :D indeed luckily enough the sound can fixed with just a switch of a button. i've kept my cayin pretty much on the tube (6922) output. in a few days i'll switch over to the ss output. it's been a while but i remember the ss being less warm (duh, no surprise there) but still enjoyable in a different kind of way. like a good wine vs. a good scotch :D i also read somewhere that 96/192khz are not ideal sampling rates because they are not multiples of red book 44.1khz rates. the very expensive mark levinson transport use multiples of 44.1khz. but i don't feel a need to upgrade my cd player and i'm enjoying it :D i've now bumped up to 25% digital/75% analogue from just 10% digital just a month ago.
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Re: upsampling

Postby Stagea » Fri Aug 13, 2010 8:11 am

conspicuous wrote:gents, thanks a lot for sharing your inputs. :D indeed luckily enough the sound can fixed with just a switch of a button. i've kept my cayin pretty much on the tube (6922) output. in a few days i'll switch over to the ss output. it's been a while but i remember the ss being less warm (duh, no surprise there) but still enjoyable in a different kind of way. like a good wine vs. a good scotch :D i also read somewhere that 96/192khz are not ideal sampling rates because they are not multiples of red book 44.1khz rates. the very expensive mark levinson transport use multiples of 44.1khz. but i don't feel a need to upgrade my cd player and i'm enjoying it :D i've now bumped up to 25% digital/75% analogue from just 10% digital just a month ago.


Multiples = generally oversampling (integer upsampling / synchronous upsampling)
Non-multiples = generally upsampling (non-integer upsampling / asynchronous upsampling)

"Oversampling" players and DACs may have DACs capable of running 192kHz or 96kHz (often advertised), but being limited by the built-in oversampler of most DAC chips, they normally just upsample to 176kHz or 88kHz when playing redbook cds. This is a cost-effective implementation, and can possibly have lesser losses. However, since the DAC is running synchronously with the source, it becomes very susceptible to transport and interconnect jitter (external DACs suffer the most, as they don't get the advantage of running I2S). With an oversampling DAC, a cheap DVDP vs. a decent CDP as transport may turn out to be a night and day difference. The main advantage of this design over NOS is that it shifts the aliasing noise to somewhere beyond the audible range (making it easier to filter out in the analogue domain). The simpler filters tend to introduce less phase distortion, and the fact that they can be set higher up the frequency range means that the effect on the audible range can be far less detectable.

"Upsampling" players and DACs generally have DACs running asynchronously from the transport (through an ASRC), which allow for resulting sampling rates that are not multiples of the original. This feeds the DAC chip with the final sampling rate (192kHz for example), (usually) with no further need for on-chip oversampling. This is clearly a costlier implementation, but the reclocking of the DAC's input eliminates some of the negative effects of jitter. These designs can tolerate far higher jitter levels without too much output degradation.
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Re: upsampling

Postby conspicuous » Mon Aug 16, 2010 9:10 pm

Stagea wrote:
conspicuous wrote:gents, thanks a lot for sharing your inputs. :D indeed luckily enough the sound can fixed with just a switch of a button. i've kept my cayin pretty much on the tube (6922) output. in a few days i'll switch over to the ss output. it's been a while but i remember the ss being less warm (duh, no surprise there) but still enjoyable in a different kind of way. like a good wine vs. a good scotch :D i also read somewhere that 96/192khz are not ideal sampling rates because they are not multiples of red book 44.1khz rates. the very expensive mark levinson transport use multiples of 44.1khz. but i don't feel a need to upgrade my cd player and i'm enjoying it :D i've now bumped up to 25% digital/75% analogue from just 10% digital just a month ago.


Multiples = generally oversampling (integer upsampling / synchronous upsampling)
Non-multiples = generally upsampling (non-integer upsampling / asynchronous upsampling)

"Oversampling" players and DACs may have DACs capable of running 192kHz or 96kHz (often advertised), but being limited by the built-in oversampler of most DAC chips, they normally just upsample to 176kHz or 88kHz when playing redbook cds. This is a cost-effective implementation, and can possibly have lesser losses. However, since the DAC is running synchronously with the source, it becomes very susceptible to transport and interconnect jitter (external DACs suffer the most, as they don't get the advantage of running I2S). With an oversampling DAC, a cheap DVDP vs. a decent CDP as transport may turn out to be a night and day difference. The main advantage of this design over NOS is that it shifts the aliasing noise to somewhere beyond the audible range (making it easier to filter out in the analogue domain). The simpler filters tend to introduce less phase distortion, and the fact that they can be set higher up the frequency range means that the effect on the audible range can be far less detectable.

"Upsampling" players and DACs generally have DACs running asynchronously from the transport (through an ASRC), which allow for resulting sampling rates that are not multiples of the original. This feeds the DAC chip with the final sampling rate (192kHz for example), (usually) with no further need for on-chip oversampling. This is clearly a costlier implementation, but the reclocking of the DAC's input eliminates some of the negative effects of jitter. These designs can tolerate far higher jitter levels without too much output degradation.


stagea, thanks for clarifying the diff between oversampling and upsampling. it would seem then that having a good transport and DAC could be sufficient to play back red book cds? this appears to be the principle behind some high end players. :)
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Re: upsampling

Postby Stagea » Mon Aug 16, 2010 10:19 pm

conspicuous wrote:stagea, thanks for clarifying the diff between oversampling and upsampling. it would seem then that having a good transport and DAC could be sufficient to play back red book cds? this appears to be the principle behind some high end players. :)


You're welcome sir. I agree with you. Both the transport side and the DAC side (together with what interface couples them) would make an impact on the final output.

For oversampling and NOS designs, it's typically easier to make a single box sound better (connected via I2S and running synchronously with a good clock) than running 2 boxes via SPDIF. This is because I2S is inherently very low jitter, while the use of SPDIF can introduce quite a bit of it.

In any case, all three designs (non-oversampling, oversampling and upsampling) can sound good, given the right implementation (and matching with the rest of the system).
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