My opinion based on almost a year and a half experience using the AX8 in a variety of situations and experimenting with it is that, in an ideal world, you should be able to set OUT 1 to 100% without causing any clipping. You can pull down OUT 1 to compensate but this means you are just working around something wrong elsewhere in the system.
Some common causes:
- You are going through a mic preamp on the mixer (or audio interface) and/or the mixer input gain is set improperly. This usually happens if you are running XLR instead of TRS into the input as the XLR inputs on mixers/interfaces are often hardwired through the mic pres (and sometimes with hardwired gain). Easiest solution is to use the TRS/line input on the mixer and keep gain at 0. Advantage here is that you aren't introducing noise/color from the mic pre and you aren't attenuating the AX8 output just to boost it on a potentially noisy mixer in a potentially (electrically) noisy environment (eg. pretty much any bar gig).
- Your presets are averaging out higher than the vertical line on the AX8 VU meter. I suggest re-leveling your presets to fix this as it means you also greatly reduce the possibility of internal clipping which can easily happen if you add a solo boost, layer some loops, plug in a hotter guitar than usual, get excited at a gig and pick harder, etc.. The amp block levels in the AX8 often need to be pulled down pretty far to get back to a safe output level.
- You are plugging into consumer grade gear. The -10dbV setting is the way to go here.
Some good reasons to sometimes set OUT 1 lower than 100%:
- You want some headroom to boost your own volume. This is useful if you play with a drummer who likes to get louder and louder as the night goes on (and the drinks go down) or if you are in a jam situation where you don't really have a good sound check situation to get a handle on levels. I've found that 75% gives plenty of headroom for these situations.
- You are in a situation where you really do have to compensate on the fly for external issues eg. junky/old mixer, confused sound guy, etc.. I have not encountered this yet but I've seen some posts in the past that suggest this does happen.
I'm always looking to improve my methods and understanding so if anyone takes issue with any of my points, feel free to chime in!