The typical values are around 2 & 75 ohms. The default setting is low, we are purposefully not recommending one setting over the other. Headphone impedances can vary (typically in the range of 2 to 300 ohms) and some users may prefer listening with high impedance headphones at the low impedance setting, while others may prefer listening on low impedance headphones at the high impedance setting. Either setting will work with any headphone, so it’s really just a matter of personal listening preference and the user can experiment with the settings. There is no quantifiable performance advantage between the settings - it really just comes down to personal preference. Users can select the setting they like best depending on the type and quality of their headphones, program material, and their own auditory characteristics.