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Q What software and computer control panel volume settings deliver the best sound when playing music using apps like iTunes and sending the digital output to a DAC? —John de Perczel

A The answer to that question is...it depends. The settings that you end up with will vary with the capabilities of your playback software as well as the performance of the hardware your computer is connected to.

When using iTunes, some DAC makers recommend setting the software volume control to 100%. At that setting, iTunes passes data to the DAC without attenuating volume in the digital domain, which can reduce the dynamic range of the original file. It’s also recommended that you turn off iTunes DSP settings like Sound Enhancer, EQ, and Sound Check (volume leveling) that can also degrade performance.

How your computer’s main operating system volume gets adjusted will depend on your software and hardware configuration. For example, when iTunes is used with AudioQuest’s DragonFly Red and Black DACs , the company recommends setting the software volume control to 100% and then using the computer’s main system volume adjustment to set levels. That’s because the computer’s system volume slider will adjust the DAC’s built-in volume controls by proxy when it’s connected to headphones. In other cases, it’s generally a good idea to set system volume to 100% when using iTunes and then adjust levels with your preamp or receiver’s volume control.

Sophisticated music playback software designed for high-res audio playback like JRiver Media Center, Roon, and Audirvana Plus offer greater volume adjustment flexibility than iTunes. With each package, there is no audible effect on dynamic range of the original file when software volume adjustments are made. Another benefit the iTunes alternatives bring: when a DSP setting like EQ or volume leveling is enabled, the software has sufficient processing headroom to apply the effect without a corresponding reduction in sound quality.