If you have source material recorded 32 bit / 192 khz native then by all means find a way to rig a SPDIF output or buy a soundcard that has one. If you are listening to 16 / 44.1 audio from CDs then resampling 14-bit / 44.1 khz data to 32 bits and rate-converting the result to 192 khz will **NOT** improve your sound. In fact, statistically speaking, it degrades the data. If the source file is 16 bit there's no way to magically create real 32 bit data out of this; It's like when you take a 1 megapixel image from a cellphone camera and put it on an HDTV screen- the screen itself has high-definition picture resolution ability but the SOURCE FILE- the 1 megapixel phone camera picture - does NOT have hi-rez data. There's now way the bigscreen TV can magically pull 1080p images out of a 480 x 640 file. Same is true with music files- doesn't matter if the files are stored on a CD or on a PC hard drive; digital audio is 16 bit / 44.1 khz and there's no juju that can make it 32 bit / 192 khz. (Some fownloadable
Some DACs do UPSAMPLING, but this isn't to make the source file sound better- this is only so you can move the antialias filter way up beyond the audioband. See, when you convert a 44.1 khz bitsteam to analog you have 44.1 / 2 = 22.05 khz noise (for want of an easier to explain term) in the analog signal. You can't hear this but it would burn your tweeters out or make your amp go crazy. So they put a filter in the analog audio circuit to filter this noise out. The filter is right at or just above 20 kHz. In fact this has some sonic impact on the signals passing through it, even those a fair bit lower than 20 khz because of the nature of the filter used; there is some phase shift and some other time-domain stuff like "pre-ringing" etc. So, the theory goes, if you upsample everything to 192 khz, then you put your filter at 96 khz which is comfortably above the audio band, and then your filter doesn't have ANY audible impact on the audio passband. That's the theory, lots of people like up-sampling DACs so maybe it really makes a difference. Myself, I have plain DACs and upsampling DACs and I hear differences but I don't know if it's the upsampling / higher frequency filters I hear or some other difference in the circuit like better parts someplace or who knows.
So, unless you have 32 bit, 192 khz files I really doubt it will make much, if any, difference. (I suppose you could do your own recording at that depth / bitrate or convert LPs or analog master tapes. However I don't know of any A-to-D converters that can resolve to 32 bits at 192 khz so I think, really, there is NO 32-bit, 192 khz native content out there.) There is 24 bit stuff you can download and also DVD-A's, and there's SACDs but there's no way to access digital data from SACD and it's 1-bit / 2.8224 MHz DSD encoded so no outboard DAC can decode that anyway.
FYI recording studios, mastering guys, and so on will often convert 16 /44.1 data to a higher rate / wider sample because it makes their digital boards and digital editing stuff more precise. They're putting their audio data through all kinds of manipulation - filters in the digital world are really just MATH - so having extra digits after the decimal point keeps their studio digital audio workstation manipulations sounding nice and clean. They downsample to 16 bits / 44.1 khz when they make the cd.
YOUR PC MAY HAVE A HIDDEN SPDIF!
Many "on board" sound chips on PC motherboards have a SPDIF but it is usually not brought out from the motherboard to an external connector, so you'd need a little jumper to go from the socket / pins on the motherboard to an RCA jack that you'd have to install on your PC case someplace. Find out what motherboard you have then go to that manufacturer's site and look at the pins / connectors on the board.
Most on-board sound "cards" have middling - poor DACs on them, so their analog output isn't the best. But SPDIF doesn't go through the DAC...... it's digital all the way.
Edited by milosz - 10/25/10 at 2:22am
