Originally Posted by sfmatt
Is there a knob to control the volume on the back of the card?
Because if you're using the Windows and/or foobar volume sliders to adjust the volume, it's the digital signal that is affected in the way I explained before getting decoded by the DAC.
What you described is analog volume control and unless Xonars are unlike all the other sound cards on the market, it's not done on the card. On the other hand amps offer analog volume control.
actually you sould not use the Windows volume to control the output signal. I do not have this card, but i'm pretty sure that you can configure the your hardware along with Windows in order to not change the final volume through the Windows volume set. What I mean is you bypass any Windows treatment regarding the audio bitstream and let the card make all the processing, including D/A and analog signal amplification. The card do not have a physical knob, but it does have a volume control on its driver/software and it is there where you should control the volume, not on Windows. What you need to realise is that any digital source which is stored in the pc (or coming from outside in a digital way) should be only processed by the STX and Windows should not interfere in the output volume since you are not using any software or hardware controlled by any other piece of software native on the OS, but rather an separate hardware controlled by a separate driver.
Originally Posted by sfmatt
Finally you're right about volume and bass but try that simple test if you have an amp:
1) Windows/Audio app volume control to the max, volume controlled by the amp
2) Amp volume to the max, volume controlled by Windows/Audio app
At equal volumes, there is a lot of detail lost in the second case: it makes high-pitched sounds disappear and the bass looses its definition and extension.
I've already done a test similar to this one. In fact, what happens here is that when Windows (or any other software) is able to control the volume of the source, it somehow process the digital samples and alter its level creating some distorsion to the signal. If you cannot get rid of software sound control, what you got to do is let the software set to the volume level equivalent to 0 dB (in mac os x it's the highest volume level, maybe for windows too), thus changing the volume at the amp only (in the case of the stx, use the knob from it's software/driver). The good thing of using the amp to alter the volume is that it will not change the signal in the digital domain, but only in the analog domain presented at the amp input, so you don't lose resolution when attenuating and amplifying it.
Windows vista seems to change the digital samples from integer to floating point values, so that when you devise and after multiply you lose less or none resolution. But, there's other thing. For this test you describe, you got to turn off any software sound enhancement tool such as equalizer, surround emulators or other things like that. If you do that you will feel much less difference. Anyway, the best thing to do is never change the volume of the sound on the digital domain, ever.