gerwin wrote:@jwt27
Thanks for sharing your observations, and glad we both agree on the YMF719 being a useful card. […]
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@jwt27
Thanks for sharing your observations, and glad we both agree on the YMF719 being a useful card.
The YMF715 (=YMF719) Datasheet says there is a Yamaha OPL3/OPL3-L build in.
You wrote: "SBpro mode is severely distorted anyway since the card does no filtering or interpolation at all in that mode. But I think that's intended."
Can you tell more about that filtering/interpolation distortion. Because Whenever I use an ISA soundcard, SB Pro compatibility is used far more often then the poorly supported WSS mode.
Maybe distortion is not the right word. Depends on how you look at it.
When you sample an analog waveform, the resulting digital signal is, well, digital. When you look at the digital waveform, it has sharp edges which were not present in the original waveform. Those 'sharp edges' result in harmonics, on a FFT spectrum analyzer you'll see audio signals above 11kHz (= nyquist frequency of the 22kHz sampling rate used in SBpro2). With sampling rates above 40kHz, you won't hear much of a difference ofcourse, since not many people can hear sounds above 20kHz.
To more accurately reproduce the original signal, a DAC can either use a higher sampling rate and interpolate between two samples, or use a low-pass filter at 11kHz to 'round' the edges. You can roughly compare this with anti-aliasing used in digital graphics processing.
I'm not very good at explaining this, especially not in English, so pictures probably say more than a thousand words:
http://www.alpha-ii.com/Info/AudioInt.html
The sound card really does not 'distort' the signal at all, the DAC actually does a very good job of reproducing the digital signal. But, it's not the same as the original analog signal. If there ever was any, that is 🙄. OPL3 music, for example, does improve with interpolation or filtering, since it was never sampled from an analog signal. (not that you would hear the difference anyway, with a sampling rate of 49.something kHz)
But now, does this 'distortion' matter? It depends on how the musician intended his music to be heard. But since we will most likely never know, it all really depends on your personal preference 😀
If you want to hear the difference:
http://www.box.net/shared/nz9jc6yc8hq44zy4plfa (3MB flac)
First part is the output from the YMF719,
Second is the same, with a sharp low-pass filter at 11kHz,
Third is rendered by Modplug in 16bit/48kHz with cubic interpolation.
