what exactly is the difference between adjusting output volume on the board vs Output 1 of my fm9 (The knob on the unit, not the block in my preset)? Does increasing output 1 of my fm9 increase the gain being sent to FOH? And then the board just alters the volume of that signal?
this concept is known as Gain Staging. generally speaking, you want the strongest signal from the first device to go to the next device. that next device should be able to
adjust to the signal coming from the first, then repeat for any further devices.
a mixer does just that. it can receive a signal from various devices into its channels, and each channel can adjust its gain/trim to balance out the signal being received.
so if i send a weak FM9 signal to the mixer, i could turn the mixer gain/trim up to get the level i need in the mixer.
if i send a strong FM9 signal, i could turn the mixer gain/trim down to get the level i need in the mixer.
generally, the stronger signal from the first device has the least "operating noise" from that device. that's known as the Noise Floor - the noise in the signal the unit makes by itself that can't really be turned down or affected. older gear had a lot of problems with noise floor. recent gear, especially Fractal, has a very low noise floor.
turning up the Output knob will make your signal be louder than the noise floor. the noise floor doesn't turn up with the Out knob. on older gear, you could easily hear this because you would plug in, have the Output all the way off, and there would already be noise in the system. the noise is coming from the hardware components through the cables connecting everything. this kind of noise has nothing to do with the tone/sound the gear is creating, just what's there when plugging in. (don't confuse this with added noise from the guitar pickups.)
that's all the general, suggested, etc. concept.
knowing that, now we can do what we want with that information and use the gear as needed for the situation.
i agree that turning up the FM9 all the way is "the best" way to use it, in a controlled situation. however the reality in many live situations is that you will be asked to turn down - you're sending too much signal.
with the FM9 turned all the way up and over XLR cable to a Mic channel, on most mixers i've used (which is almost everything available) the channel gain we mentioned above has to be turned way down, or even all the way down. technically, this is fine. when i run sound and do this, it sounds great, full, no issues at all.
however, many sound guys for some reason have learned that you
cannot turn the mixer channel gain/trim down below 12:00 or it will "sound bad." i've worked with thousands of people over the years. many, many have told me this word for word.
because of this belief, when i send the FM9 knob all the way up, they say WOAH that's way too much level, turn down! i look, and sure enough they're at 12:00 on the trim. some i ask to try something silly, and turn down the trim. they do, the level is now good, and they're like oh. most say no and have me adjust.
so i end up turning the Out knob to about 10 o clock to 12 o clock to give them the level they need.
now with everything mentioned above, you might think OH NO it's not all the way up my FM9 will sound so bad now.
not true.
the noise floor of the Fractal gear is so low, that there really isn't any additional noise with a low setting. i've been forced to use my Axe-Fx around 8 o clock on the knob, barely turned up, and it sounded good. no additional noise.
so for the Fractal gear, i would say any position of the Out knob will sound good - i wouldn't
want to use the knob so low, but it's fine. and yes, i still say that all the way up would be "better" for practical purposes, but not 100% necessary "or i'm not doing the gig" kinda thing.
but what many have issue with when doing this isn't the tone or quality of the Fractal gear, but the affect of the Mixer channel being turned up so much.
going XLR out from the Fractal in live situations, you will almost always be going to a Mic channel on a mixer. Mic channels have a Mic preamp. this preamp can "color" the sound as the channel gain is increased.
so when i run sound and go to a Mic channel and turn the channel gain all the way down, there is little to no "coloring" of the sound because the Mic preamp isn't really doing anything.
however, when the mixer Channel gain is at 12:00, it probably is "coloring" or changing the tone because of the mic preamp. in my experience, this is just a bit of EQ that is different. others have described this as completely ruining all tone. you'll probably have to make your own determination. some older and usually cheaper mixers also have more noise with the Channel gain turned up. this should be easily heard, and is usually only present when the Channel gain is almost all the way up - something that should rarely be necessary.
(also, some people prefer what the mic preamp does. some say it rounds out the high end, compresses the low end and sounds better. some the axe into an additional preamp before a mixer for this as well. no rules, just preference.)
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so it's probably best to have your FM9 turned up as much as possible. a strong signal from the first device will go to the next device, and the next device doesn't have to compensate for a weak signal which could add more noise (from the mixer preamp). you'll probably be in situations though where you can't do that and have to turn the Out knob down. in my experience, this has always worked out with the same tone and quality i always get.
in my experience, the thing on mixers that CAN completely ruin a tone is compression. if the mixer operator doesn't know how to use a compressor, it can squash things so much it ends up sounding like mush, more noticeable on higher gain tones. so when possible, turn off any compression in the mixer channel as a starting point.
