Wow I should try that sometimes. They line out is shared right?
Yes, in general, if you drop the bass on the player, it makes the signal less muddy, slyly don't get a double amping effect. And you only need to drop the bass a couple notches. Primarily the mid-bass slider (50-80hz). The sub-bass (20-49hz) frequencies usually don't do much on most players.
For example, if you have a flat EQ, drop the mid-bass slider down 2 notches, give it a shot like that, or possibly just raise everything else up after the mid-bass slider two notches. By doing that it will provide the right amount of bite on guitars, pianos, cymbals, etc..
As always, this is a generalization, so depending on the earphones you are using it may need more or less raising or dropping.. But in general it's a very safe bet to start with those settings.
With the Q1, depending on the music, Rap, RnB, Techno, etc, it's best to turn on the Bass boost. If it's some form of Country music, Heavy Metal, Classical, you can be the judge for yourself on that one. But that's what I love about the Q1, it's a pretty versatile little unit.
In fact, one way that really added an insane amount of clarity was connecting the Q1 by the USB from my device then plugging my headphones in to the Line out of the Q1.
By doing that, you bypass the Bass boost function, and volume knob. So you have to use your player as the volume adjuster, but the sound you get is fantastic.. It easily rivals the iBasso D14 which is $200. Anytime you're bored, give it a shot.. You'll be surprised with the results.