Quote:
Originally Posted by ]|[ GorE /img/forum/go_quote.gif
Eager for the Audio Precision results.
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Bah today I tried everything I could think of to get the Digital-In on my X-Fi to work but for some reason it doesn't (I enabled the Digital I/O, and un-muted Digital In in the mixer...looks like there's nothing else I can choose). I read somewhere that the X-Fi Digital In needed +5V digital signals to drive it, so I even hooked up the AP's SPDIF signal to a buffer so it was boosted from 2.5V to 5V...no luck. I was really hoping to be able to drive the X-Fi with the AP so I can make sweeps from 20Hz to 20kHz and produce pretty graphs for everyone to see
So far, the measurements I made with the AP and a software test tone generator were some THD+N numbers at a few frequencies and a few different volume settings. I also made some FFT plots.
I don't remember all the exact details now but in case some of you are curious, here are some numbers I remember off the top of my head:
X-Fi ExtremeGamer Fatality Before Mod (All effects off, Wave Volume 100%)
1) Entertainment Mode, Lineout @ 1.35V (master vol 85%): THD+N @ 1kHz: -96dB
2) Entertainment Mode, Lineout @ 2.2V (master vol 100%): THD+N @ 1kHz: -94dB
3) Entertainment Mode, Digital Out (master vol @ 85%): THD+N @ 1kHz: -101dB
4) Entertainment Mode, Digital Out (master vol @ 100%): THD+N @ 1kHz: -103dB
* I took the Digital Out numbers just to get a reasonable reference as to what the best result may be without all the analog output circuitry. Looks like even with the lowest distortion opamps and ultra-low noise resistors, the output will hit a wall at around -103dB.
This is just my first round of tests as I get things set up properly. The next time I measure the card I may actually use a realistic headphone load too (the numbers above were taken @ 100K I think set from within the AP). I'll get some more numbers after I change the opamps. However, if anyone knows how to get the Digital In to work on the X-Fi, or if there are suggestions to improve testing, let me know!!!