This is more or less "solved". I've been sticking to the direct outs but it's nice to know the aux outs are there and useable for such things. I have however learned quite a bit (and relearned a lot) about my mixer and mixers in general. Thanks, all. Cool convo.
 
OP below for those who are curious.
 
Hello, all. Hope everyone is well. I posted a similar thread like these a couple years ago but really didn't know WTF I was trying to ask so here I am again, hat in hand, looking for scraps of advice.
 
I will list the applicable gear I have first so everyone knows what I'm looking at.
 
Mixer = Mackie CR1604 (old analog American version... not the fancy new ones with the digital connectors)
Connections (that apply to this convo):
 
1) There are 8 direct outs for the first 8 channels. They are post Trim/EQ/Fader. There are no separate controls for the output level coming from these direct outs. The level being outputted by these direct outs is basically controlled by adjusting the fader or input trim. They also have a bunch of other features based on what type of cable is used and how far it's pushed it but that doesn't matter for what I'm doing/asking.
 
2) There are six Aux outputs. Each channel has 4 Aux level knobs that allow that channel to be outputted to the corresponding Aux out connector (so each channel can be sent to four different Aux outputs individually, all at once or in any combo by adjusting the corresponding level knob). There is a button that switches the 3/4 aux outputs to be sent to the 5/6 outputs instead and then the 3/4 knobs control the output level (but that't just a routing thing and doesn't matter really for this convo). There is also a switch on each channel that makes all of it's Aux outputs Pre or Post EQ/Fader.
 
Interface = Focusrite Scarlett 18i6
Connections: It has six 1/4" line ins on the back which are what I am using to connect the mixer to as well as the multi ins on the front panel (it also has a bunch of other stuff that don't apply here).
 
Things being connected: Line 6 Duoverb (I'm using the two XLR balanced outputs but it has line outs, effects send/returns, etc), Traynor TS-140 (has a single XLR balanced out and confusing old school ins/outs... it is very old and I have not tried much with it yet but the XLR out will probably be used) and the usual mics for vocals, micing the guitar speakers, acoustic guitar, whatever.
 
So I have tired of using the multi ins on the Scarlett. They sound good but are limited as they only have one control for each of the two channels (input trim). There is no EQ section or other goodies and if I engage phantom power it affects both inputs. Also... well there is only two XLR inputs which is limiting in itself. I also get concerned about wearing out the semi cheap feeling plastic Multi In jack (one of my very few complaints about the unit).
 
With the Mackie I can have Phantom Powered mics and dynamics running at the same time, the pres are nice, there is a sweet sounding eq section, it's sturdy as heck, etc. Also since I discovered my TU-2 may act as a splitter I can send the XLR outs of my Line6 (or whatever) and have a fully processed signal (including mics on the cab) while still sending a dry signal to the Scarlett's multi in (for amp sims).
 
So the conundrum is do I use the direct outs which have less controls or the Aux outs to feed the Scarlett? Most of the stuff I'm reading (including the manual for the mixer) is saying to use the direct outs to send to an external recording device. However I also see people saying that IF direct outs aren't available on a mixer using Aux outs is a solution.
 
Basically considering I can seemingly get more functionality out of the Aux outputs (because I can control the level going to the interface AND bypass the EQ if I so desire which is doubtful but it is an extra option... and I could mix channels together if I want which again seems doubtful but it is an option) the only downside seems to be that I would have two less possible outputs from the mixer which I probably won't need in my modest home setup. Even then there are many other routing options that I could use if I did need more outputs.
 
Is there some magical awesomeness about direct outs (which I actually bought this board for because I didn't understand Aux routing) that I am overlooking? Crosstalk between channels? Different gain considerations (this board touts a really wide gain range to cover most applications from the way the manual brags)? 
 
Just looking for some insights as to what the best way to proceed here is and/or things I should be aware of/look out for before proceeding with further tests. So far the direct outs do work and have for a long time but if I can have that extra level control it would be really helpful methinks.
 
Cheers and thanks. I'm a busy little Beep these days so I'll be back and forth.
 

Cripes that was long.
 
tl;dr version...
 
If I want the signal from my mixer to go into my interface and then to Sonar is there a any benefits to using Direct Outs vs. Aux Outs?
 
Details are in the novel I just posted in the OP. lol

Oh and another benefit to using Aux outs is all 16 channels have access to the 6 aux outs (4 at a time with level controls for the chosen 4 outs) whereas only the first 8 channels have the direct outs. I could have cables hooked up and channels set for specific things (vox, amps, etc) and just unhook them from the Scarlett when not in use (and mute the channel on the mixer). Might be a time saver.

I would imagine the direct outs have less noise than the aux outs. Fortunately it is not an either/or situation, 4 direct and 4 aux out might be a good compromise.

scook
I would imagine the direct outs have less noise than the aux outs. Fortunately it is not an either/or situation there might be a good reason to use both. 4 direct and 4 aux out would be a good compromise.

Interesting. Any idea what would be the cause of that noise? Keep in mind this is not a cheap board (supposedly). It's supposed to be suited for pro film/audio applications and Mackie goes to great lengths to claim all connections and controls are equally awesome (even the headphone output).
 
However that is coming from them so who knows. It is from before they moved production offshore though so this is the old Mackie. Not the newer, less desirable stuff.
 
Thanks.

I guess another factor that I hadn't considered is for the most part all input going through the mixer for my current purposes would be the same signal (like me playing a single guitar part being recorded from multiple sources or vocals being recorded through multiple mics). So it's not like I would have different instruments/performances going through the board at the same time. So any channel bleed probably wouldn't matter BUT I will keep my ears open for that kind of thing anyway.
 
Cheers.
 

Ah, scook... you have given me an idea to test the difference. I only have 6 direct Line Ins on the Scarlett (I'd be concerned the Multi Ins on the Scarlett might color the sound thus ruining the test). From the mixer I could use 3 direct outs and 3 aux outs on the same signal making sure the levels are matched as evenly as possible once they hit the Scarlett. I record all six and compare the two groups of three.
 
Thanks.
 
Still looking for any other thoughts on this though.

aaand I guess I wouldn't need to do all six. Just two but I have snakes that can handle that many connections. It would be good to test the channels anyway.
 
edit: I'm guessing I could do that reverse polarity null test thing to compare the signals too. hmm...

Beepster
Interesting. Any idea what would be the cause of that noise?

The additional circuitry needed to get the signal to the aux port.

scook

Beepster
Interesting. Any idea what would be the cause of that noise?

The additional circuitry needed to get the signal to the aux port.

Ah. Yeah, that makes sense. The polarity trick should reveal that type of thing though I'd imagine. Considering people spend good money on software console emus that type of noise might be desirable.
 
Thanks again.