analogsurviver
Headphoneus Supremus
- Joined
- Jul 2, 2012
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I'm becoming quite confused as to where the noise is actually occurring......
If we're talking about a purely digital operation - like converting a DSD file into a PCM file using Audiogate - then that is not a real time operation. Within reason, even a very slow computer should be able to do a perfect job, even though it might take a lot longer to finish. If that's what we're talking about, then all this talk about "reaching the computer's limit" is meaningless unless a specific piece of software simply faults when asked to perform certain conversions.
HOWEVER, then I see it mentioned that "there is a good outboard DAC connected". If we're talking about having a program convert the DSD file into PCM "on its way to the DAC" rather than writing the output to a file, then this isn't implausable at all. Transferring digital audio to a DAC most certainly IS a real-time operation, and overtaxing the computer most certainly CAN result in odd noises coming from the DAC - because the computer has become unable to deliver a steady stream of numbers to the DAC. This typically results in what I tend to refer to as a "screeching" or "chittering" noise. This noise is being caused by the computer sending a non-continuous stream of audio information to the DAC, and is the result of the DAC then trying to decode this defective audio stream.
The important point here is that this should ONLY occur when we're playing audio through the DAC... and should NEVER occur if we're doing simple file operations. In other words, it could happen if you were playing a DSD file through a PCM DAC - and letting the player program do the conversion as the file is played. In that case, it's quite possible that the choice of using certain filters in the player could make the difference between the computer delivering a steady stream of audio to the DAC or failing to do so. However, it should NEVER occur if you were to convert the DSD FILE into a PCM FILE, then play the resulting PCM file... and the distortion should never be present in the PCM file itself. (I recall trying a certain player program which offered the option of upsampling the audio as it was played, and offered several filter choices. Some of those filters required so much processing power that my quad-core desktop computer with 8 gB of RAM wasn't capable of playing audio using them - and produced the characteristic chittering noise after a few seconds whenever it tried. Again, note, though, that the error was occurring inside the computer, to the audio stream on its way out to the DAC - and there was no flaw or error present in the actual file that was playing.
You are correct - converting DSD file to PCM file and then playing back should not result in any such increase of noise - it will just take so much longer to convert.
REAL TIME converting and playing (from DSD to PCM, as in Korg Audiogate - or vice versa in jRiver19 , for example ) or so called converting in the fly IS another matter. jRiver specifies PRECISELY
http://wiki.jriver.com/index.php/Windows_System_Requirements
how much computing power you got to have
http://yabb.jriver.com/interact/index.php?topic=54396.0
in order to use the software in full measure - and will stutter, noise and hiccup if it is not met.
FFT IS more demanding than just simple playback of 192/24. For those who think this is another audiophile myth, load Foobar2000 and start using graphic features like VU meter, spectrogram, etc, etc - and you should reach a point, sooner or later, when things will start sliding downhill.
Except if you have infinite computer power.