It really depends on the genre of the music, but for an agreeable all around tone, on my Ampeg PF800, gain up so the clip light occasionally flashes, bass boost on, bass straight up at 12 o'clock, mid at about 10 o'clock, mid selector on 800hz (middle), treble at 12 o'clock. On my Hartke TX300, gain up until the clip light occasionally flashes, shape switch off, Bass at 11 o'clock, mid at 9 o'clock, treble straight up at 12. I always use a TC Electronic Spectracomp bass compressor which allows me to boost certain frequencies while compressing other frequencies to shape the tone. It's usually set between 12 and 2 o'clock depending on the genre and how much bass or midrange is out front and audible. To me it is the most useful bass tone shaping tool made.