My nephew the sound engineer told me to take it out of the mix because it was coloring the sound. I only use it to control the volume coming out of my Edirol FA-101 into the powered Mackie monitors. Boy, was he right. The sound was very boxy, probably caused my some midrange boost. Now I have to control the volume coming out of my computer so I don't blast the speakers and my tinnitus riddled ears. I don't like doing it this way, but until I get one of the passive single knob volume controls this will have to do.

Have any of you experienced this and if so do you have any suggestions on which monitor control boxes I should look into?

Hmmm... I use a 1402 VLZ and never thought to test it for coloration. It would be easy enough to set up an A/B test. I'll give it a shot later.

I agree with brundlefly as well.  For many years I used one of the earlier 1604's and I was running analog and digital synths through it at the time. I found it was really transparent in its sound and the synths never changed their sound for going through it.  (I tested quite a few mixers in this role and the Mackie came out on top. In fact Mackie mixers are known for their very transparent sound and the fact they don't change the sound at all)
 
If everything is set totally flat the sound from input to output should sound like unity with virtually no sound change at all.
 
Are you running your computer outs into the line input channels. Don't use any Mic Pres for this role remember. Check that everything is set totally flat EQ wise.  There should not be a major difference with and without the mixer at all.
 
But if you are using it just to control your level for your speakers then yes perhaps some sort of monitor controller might be a better option. (A passive one maybe for your piece of mind!)

Even an SSL E-Console's going to color the sound--albeit, in a pleasant way. Your speakers color the sound. The result is the key. If you work on inferior gear and produce killer mixes, you're going to have other people grabbing the same gear wherever they can. I wouldn't read too much into that. For Mastering purposes, the most transparent gear is the thing to shoot for, unless the desire is to color the sound. Aside from that, using Sonar and a 1202VLZ will probably do less damage than dropping in some modeled plug-ins. 

Go fix the room, or fix the instruments, talent, mics, pre-amps, clocking, monitors etc. before you spend too much time on OP-AMPs inside a listen-back mixer.

Thank you for the replies. Yes, I have been using the line input channels. It is not only me. I have seen and heard it myself with another 1202VLZ in a mixing room of a recording studio.

There is a serious difference when the 1202VLZ is taken out of the equation.

The room is treated.

I have a Mackie 24x8 that I haven't tried, maybe using the direct outs will bypass any eq.

Viamichael
My nephew the sound engineer told me to take it out of the mix because it was coloring the sound. I only use it to control the volume coming out of my Edirol FA-101 into the powered Mackie monitors. Boy, was he right. The sound was very boxy, probably caused my some midrange boost. Now I have to control the volume coming out of my computer so I don't blast the speakers and my tinnitus riddled ears. I don't like doing it this way, but until I get one of the passive single knob volume controls this will have to do.

Have any of you experienced this and if so do you have any suggestions on which monitor control boxes I should look into?

Hmmm... I picked up a new 1202VLZ almost twenty years ago for my garage band setup.  Never really noticed anything off with the mixer.  But maybe we weren't all that either.  I had more trouble with my PC and sound cards back then.
 
I usually kept my EQ's at Unity or below, as well as all of the gain knobs. I always thought it was pretty flat, unless someone monkeyed with the EQ or something.
 
I ran all of my hardware synths audio outs to the line ins #5-12 on the patchbay.  My buddies guitars and or mics were the only thing that ever went into the mic pre-amps.
 
I believe that I hooked up my M-Audio Delta 44 soundcard with 2 in/2 out mode using the Mackie tape in/out hookups, and then used the control room outs to my amp and speakers.  This little thing had more routing options than I could ever need, LOL!!!
 
I don't have it currently hooked up to do any a/b testing with, since I'm mostly playing in the box these days and all of my sound goes directly out to the monitors.
 
But you do raise an interesting question.  I wonder if that's why Cakewalk decided to add console emulation to the Pro Channel and sell it as a "feature"? 

It depends on how you set the mixer up to monitor the DAW signal along with the features of the mixer.
Need to check the manual for setup.
 

Viamichael
There is a serious difference when the 1202VLZ is taken out of the equation.

I think something's not right with your test conditions or you particular 1202. I just spent an hour doing various blind A/B tests of parallel analog sends to my 1402 vs. a direct analog loopback, and I would gladly challenge anyone to consistently identify which is which. I tried both line level channel strip inputs with EQ's centered and Aux Returns that have no EQ, and got the same results.
 
I also found that phase-inverting one input canceled the other to approx. -30dB below the source signal level. What was left was probably due more to A/D/A conversion differences and non-linear phase shifts between channels on the MOTU than anything else. And fiddling with any EQ, either on the Mackie or a plugin in SONAR created an immediately obvious difference.
 
Based on this, I would have to agree with others that the coloration of your monitoring system and your room are going to be far more significant than anything a properly functioning Mackie is going to do when used as a simple attenuator between your interface and monitors.

I hear all your thoughts that most of you aren't buying this, yet you say that the monitors and the room effect the sound more. This thinking confuses the question. The monitors are the same and the room is the same. Nothing changed except to take the 1202 out of the equation. And, this was replicated in 2 completely different studios.

Viamichael
I hear all your thoughts that most of you aren't buying this, yet you say that the monitors and the room effect the sound more. This thinking confuses the question. The monitors are the same and the room is the same. Nothing changed except to take the 1202 out of the equation. And, this was replicated in 2 completely different studios.

Maybe you are dealing with defective channel strip(s)?
 
To rule this out, try connecting your audio interface to the "Tape In" source.  There is no EQ on that one.
 
Then select only the Tape source, and center the Main Mix and/or Control Room knobs.  Any difference?