When I’m playing music on my computer, in iTunes for example, there are three places I can adjust the volume. I can adjust the volume in iTunes, which affects only that application. I can adjust the systemwide output volume. And finally, I can twiddle the volume knob on my speakers.
How should I adjust these various settings for maximum quality? I assume that, before leaving the computer, all the adjustments are digital, so they shouldn’t affect the quality - but the amplifier on my speakers is obviously analog. So it might make sense to crank up the volume coming out of my computer, so that the signal doesn’t need as much amplification in the speakers. However, it might be the case that my sound card performs poorly at high volumes, and that relying on the high-quality amplifier in my speakers would be better.
I’ve never been able to hear a difference between any of these options, but I’m curious.
From what I’ve heard, everything the sounds goes through adds a bit of noise, so the louder the sound from the outset, the less it needs to be amplified, and the less the extra noise for each component will be amplified. It sounds reasonable that software doesn’t add much noise, so I guess you could turn all your software knobs to max, and have a relatively low setting on your amplifier.
(ie, low sound from computer + low noise from amplifier would mean loud noise if you wanted to increase computer sound by turning the amplifier knob, whereas if the sound from the computer was already loud, you wouldn’t have to amplify it and the extra noise with it)
You probably want to keep the audio output from your computer somewhere close to the maximum, just not so loud that it overloads the input to your amplifier.
The above posters are correct: you generally want to have all the steps up till the last as high as possible without overloading / distorting the subsequent stage and then adjust the final output volume using the last stage (the volume knob on your amplifier or speakers).
By the way: it is possible with some programs/drivers etc to turn up the volume high enough to cause clipping in the digital signal. If that happens, it will cause a VERY noticable distortion of your signal. Otherwise, turn the digital sound up as high as it can without overloading the analogue stages.
While setting all the volume control before the last to their maximum value before clipping answers your question with regards to optimum audio quality, it does neglect one of the main purposes of gain (volume) controls. You want to have as much useable range of adjustment as possible on at least one of the controls.
So if the iTunes gain is at max and the Windows sound control panel is at max, you may have to have your speaker volume knob almost all the way down for a comfortable volume level. So now you effectively have bewteen the 0 and 2 positions of the knob to adjust the sound from silent to really loud and it takes a safecracker’s touch to dial in just the right volume.
So the better answer is to adjust each gain control somewhere near the middle of their ranges so that the control you want to use as your master volume control has a good deal of range to operate in. Noise in modern amplifiers is quite low even for the cheapest powered speakers.
In many electronic circuits, the general rule is to equally distribute the gain among the multiple stages of amplification. This avoids overloading any one stage and maintains headroom.
When I’m setting up my subwoofers in my car, I turn the stereo to as loud as I’ll ever listen to it at. Then I’ll turn the subwoofer level up as high as it goes, and then crank the gain on my amp until the bass notes start to distort. That way, I can have as much bass as possible when everything is as loud as I listen to it, without having to worry about distortion from the drivers seat. It is virtually impossible, sans certain songs, to get distortion in this way.
The manuals to many devices I have had (yes, I read them) recommend that you set all the earlier knobs to around 75% and use the last one (speakers) for volume control. This is much in line with what has been said of setting them as high as possible without distortion.
And as also noted, it leaves me plenty of range in my speakers to set the volume to my comfort.