The Chicago Alembic Gathering has forced me to rethink my OD/Distortion pedals, which I have spent the last several years experimenting with and amassing. I thought I had it perfect...until the Bag End jam session.  
 
The problem seems to be that I based my selection on the fact that I was playing at or slightly above acceptable household volumes and pretty much standing on top of my amp (5-10 feet away). At the gathering, with the volumes SIGNIFICANTLY higher and my standing quite a bit farther away, I found that my Keeley modded Tube Screamer produced amazing tone! I have NEVER found this to be the case at home.  
 
The problem is that, after all these years, I've finally found a small group to jam with and I've got a guy making me a custom pedalboard a la Pete Cornish. I don't know if the pedals I've come to love while playing in my den will be the perfect ones for playing in a band.
 
Bottom line...
 
I never thought that pure volume (not natural tube overdrive) and distance from the amp contributed so much to tone.

Jonathan:
 
Ahh, they certainly do.  I hate playing right on top of my amp.  Congrats on the step into ensemble-land You might want to try out your stuff with the group before you finalize the pedals to be mounted in your board.  Perhaps give that Seymour Duncan Twin Tube Classic another spin around the block?  
 
Bill, tgo

Crank up a 12 pack of budwiser smoke a few good joints & Distort all your natural senses.............thats the best distortion!

Kevin,
 
Guess that's real natural distortion!
 
 
 
Bill,
 
Funny you should say that. I pulled it out of the closet and plan to bring it with me to Cali. See you in a couple of weeks.
 
Later...
 
Jonathan

I get my distortion right out of the amp, with the BoogieStack.

Jonathan,
Glad to hear you're playing out. For me, there's nothing on earth like the feeling of ensemble creative collaboration.  
Have a fantastic time!
Mike

Mike,
 
Yeah...the gathering really gave me the fever. The rest just fell into place. Like they say, it's when you finally stop looking for what you want that you get it.

I always tell beginning guitarists that one hour of playing with others is equal to ten hours of practicing by yourself.  And one hour of playing on stage in front of an audience is equal to ten hours in the studio.
 
Bill, tgo

Yeah...the gathering really gave me the fever.
I feel you on that one Doctor John - I'm currently without a band and after that weekend I need to get out and JAM!!!.  
 
Bill you are correct also - when you are live in front of people you better have your A-game .... or you can just tell them that you are playing avant garde jazz! ;-)  
 
Which I did play some of in Chicago.:-D

For the past year I've been practicing at household levels on top of my rig as well.  The one time a few weeks ago when I jammed with a guitar player and drummer at volume, my tone was terrible (so was my playing; I had forgotten how to play with a band).  Recently it seems like every day I'm rethinking and changing my approach to tone.

One thing I've definitely noticed is that, when I adjust everything for playing on top of the amp and then move way out in front, the tone is way too trebly. Why is this?

it is the nature of the physics of the higher frequencies be more directional. The higher frequencies have a different dispersal rate.There are many variables that can be part of the equation.

Jonathan:
 
Is this with an open back cab by any chance?  Some open back cab designs result in more bass going out the back (my new Pritchard Amp has what he calls a tunnel back design to accentuate this).  You may be hearing this bass overemphasized when you're up next to it, but hearing a more accurate tone when you put a little distance between you and the speaker(s).  I prefer to play at least 6-10 feet in front of my amp, and even more if the venue allows.
 
Bill, tgo

Bill,
 
Both amps are closed back. I'd have to agree that the more accurate tone is farther away from the source. BTW, can't wait to hear that Pritchard.
 
Later...
 
Jonathan

Jonathan:
 
Is you amp on the floor, or raised up from the floor?  As Wolf (Sonicus) noted above, high frequency waves are more directional as they are smaller and don't disperse as widely as the much larger bass waves.  This is why many stereo speaker systems come with two small satellite speakers and one woofer.  You can discern direction of the higher frequency waves emitted from the satellites, but not of the lower frequencies from the woofer.  If your amp is on the floor, or well below your ear level, try either raising it up on a chair or table, leaning it back so it points at you (like Fenders with the silver swing-out legs on the side), or kneeling down to get your ears more on the level as the speaker.  You should hear the tone more accurately.
 
Bill, tgo