I figured it out - there is an "avoid clipping" toggle which prevents the volume slider from going all the way up. 
 

I also mix in mono at first. I have a little Auratone clone that I constantly check the mix on, too, even after I have moved to mixing in stereo.
 
For mixing the bass I also use a great trick I picked up from Danny Danzi.  I monitor through the Auratone, and start playback with the bass right down.  I gradually increase the level until I can hear it, and then back it off a little.  This has improved my mixes no end.  I always tended to mix the bass too loud, but now it sits much better in the mix.

DO you use your hi and low pass filters on EVERY track?   You need to roll off all wasted low end and even high end where it is not needed.  Headphones usually do not produce the same lowend as speakers in a room.    This was an issue I had when was still more of a novice.    Most things like guitars and vocals and keys don;t need anything below 80 - 100 hz.  You need to listen but as a rule hi pass all that stuff.   Bass and Kick can also be hi passed but most like 40 or 50 hz.  use a 12 - 24 db slope.   This will clean up you mixes incredibly.  The more you use this technique the better you will understand it and properly tune each track.  All the build up of lowend cuases mixes to sound aweful.    Highend too but not as obvious.

Vastman
Go to sonarworks and pick up their headphone calibration system.  They have modeled a long list of headphones and their system works wonderfully on my KRK 8400's... you have many options, as you'll see once you arrive at their site.

 
haha for near $600 I think I'll figure it for myself!

joden

Vastman
Go to sonarworks and pick up their headphone calibration system.  They have modeled a long list of headphones and their system works wonderfully on my KRK 8400's... you have many options, as you'll see once you arrive at their site.

 
haha for near $600 I think I'll figure it for myself!

What on earth are you talking about? The basic headphone calibration plugin is $69. 

I've got my powered speakers connected to my music computer now.  They aren't centered, which is a bit of a pain, but at least they give me a second "glimpse" of what a song's mix is like. 
 
Unfortunately, they still don't sound as boomy as the stereo in the lounge.  So, I still need to compensate for [apparent] lack of bass while mixing. 
 
Is there a quick way to get a visual summary of the bass/treble balance of a song?  Sort of how we can quickly spot loud and quiet parts by looking at a waveform in a standard audio editor? 

Here's what you have to be wary of: falling into the trap of assuming any one of your reference playback systems and spaces is the one that sounds "right", and attempting to correct your mix to suit it.
 
When I got my first set of proper studio monitors, I expected them to fix everything. I was unhappy with how my mixes sounded in the car, which was equipped with what I'd been led to believe was a very good system. I also had a decent stereo in my TV room, but didn't like its sound, either. I'd also tested on friends' stereos and in one semi-pro studio - none of which sounded like my home studio.
 
My epiphany came when I realized that each reference system sounded bad in a different way. The car was boomy, my rec room system was thin, and my friends' stereos all exhibited varying degrees of too much bass.
 
That's when it hit me that no alternate playback system could be trusted to establish a baseline reference. I was going to have to try and achieve that in my studio, to somehow create an environment that was honest and middle-of-the-road, and then EQ my mixes for the statistical center. And to accept the reality that my mixes would never sound as good anywhere else.
 
Around that time I read Bob Katz's book, Mastering Audio, which argued for exactly such an approach. I also read the Master Handbook of Acoustics, which explained why having good speakers doesn't guarantee accuracy. I learned how to analyze my room so that I'd at least have a picture of how it was lying to me.
 
Slowly, the puzzle pieces fell into place. The first step was rearranging my room to mitigate resonances, followed by the addition of acoustical absorbers. Later, I moved my operation out to the garage where I could leverage the larger space and install more extensive acoustic treatments. The bigger room meant fewer problem resonances, and my speakers could be positioned far from walls.
 
But the single most effective action was to assemble a collection of well-made commercial recordings to use as audio references. I analyzed them for spectral and dynamic characteristics, and - most important - sat and listened to them for hours on my monitors. Voxengo SPAN was an indispensable tool, as was Adobe Audition. You can't do it by visual aids alone, but you can at least establish an acceptable range and know when you've gone outside it.
 
I'd read an excellent book called Sound Reproduction by Floyd Toole, which I highly recommend. It talks about the link between acoustics and perception, how our ears naturally compensate for aural flaws, and how your brain can train itself to recognize what a good mix sounds like regardless of the environment. Trippy stuff, but grounded in science and it really works.
 
Nowadays, I rarely look at spectral graphs. Not because they aren't still useful, but simply because I no longer need to rely on them. Ten years listening to the same speakers in the same room has trained my brain to know when it's right or not right. SPAN still resides on every master bus, but it's mainly there to show me the ultra-low frequencies that I can neither hear nor reproduce.
 
 
 
 

Pricey but effective if you MUST mix on headphones.
 
Ultimate Ears In Ear Reference Monitors
 
I have them and they really are "flat" IMO.

I use IK multimedia ARC 2. It is for room tuning, but also has a great feature for testing mixes in various environments. Works really well.
 
http://www.ikmultimedia.com/products/arc/
 

This mix issue is still plaguing me.  I've tried to reduce the bass before mix down, but that's not fixing the problem. 
 
What I'm finding is that it's not the high level of bass that is the problem; it's the lack of treble.  I just listened to a few recent tracks with a new computer, hooked up to my stereo, and they all sound muffled.  I played them with VLC, and used VLC's EQ to increase the treble, and the tracks sounded great again.  And the the bass sounded fine too.
 
So, I don't need to reduce the bass; I need to increase the treble of the entire song before mix down.
 
I think the simplest way to do this is to put an EQ effect on the master track.  When I am ready to mix down, enable the EQ effect, and crank up the treble, ignoring the fact that the track might seem too trebly with my mixing headphones.  Then mix down.
 
Does that sound like a decent strategy?
 
Or is there another type of effect (or tactic) I should be using to improve the treble balance prior to mix down?

I don't think ARC2 can help me much, since by necessity and preference I mix with headphones. 
 
I'm looking for a very basic fix: increasing the amount of treble in the mix downs. 
 
Is an EQ on the master audio track the best way to go?

Sorry - The phones part didn't register.
 
Sonarworks and headphones to match or A/B with reference tracks.  Or both :)  I would go with Jonesey's suggestion though as far as where to do the EQing.
 

Tripecac
Thanks a bunch, guys!  It sounds like the best way to get good mixes is to mix on good speakers.  Like fireberd, I have some Samson Resolv 6.5a monitors, but they've been sitting in their box for about 5 years now, mostly because we've been renting houses with thin walls and no sense of privacy (having 2 small kids doesn't help since they'd bang on the door the instant they hear sound emerging from my office).  Perhaps when we get our own house, and the kids get older, I'll be able to break the dependency on headphones but until then I'm afraid I'm stuck.
 

Hello ,
had for several years a compareable situation and give the monitors a try -
and to my surprise I managed much better mixes at  low loudness and the kid adapted 
hearing music out of my office.
I learned that good studio monitors work at low loudness.
 
Why not giving it a try ?
regards
 

Anderton

jpetersen
 
For this reason I start off mixes in mono so the instruments will "collide" with each other as much as possible. Then, you can adjust EQ to emphasize or de-emphasize particular instruments. Once everything sounds distinct and has its own space in mono, when you start creating a stereo field the whole mix widens up and creates a full, well-defined space. It's also more translatable, because the playback system's frequency response becomes less crucial as you've already done frequency response tailoring. You're not counting on the playback system to be capable of nuanced response.

This is actually something I do quite often, Ill build an entire session in mono.  It helps me avoid trying to be to clever in my mix when I should be trying to keep it simple.   I would spend all this time doing super tricky stuff, manipulating the stereo field with all of this trickery... get to the end of the mix, and then finally click that mono button... and it sounds like feeding time at the zoo.... (cell phones.. for example... a huge source of youtube and soundcloud plays.. are in mono...)..  A huge source of plays are youtube and facebook video... soundcloud.. etc..  people will hear it on the speaker of their cellphone which is ... mono... (unless they use headphones)
 
As far as low end, Ill high pass percussion like tamborine..shaker etc.. but a traditional high pass will potentially create a peak above where it is passed... so if you use it to make something less "boomy" - all of a sudden it might become a little "muddy" (150-300ish).. or "cardboardy" (400-700ish).  Some eqs.. like the pultec style, use this peak and dip in a super musical way more than others. 
 
I used to high pass everything... and it has a sound for certain.   
 
One of my preamps is a black lion b173.. a neve clone.  It gets its sound by creating all of this mild overdrive in the low end, and makes everything it touches much bigger and fatter as a result.  However - if you looked at the rta you would see all of  this low end noise.  I started getting great rock guitar sounds when I began using it... so here I learned that when I high pass rock guitars.. often they sound wimpy..
 
Use the sonar eq - it has a great default rta on each channel and see what is actually happening down there.  
 
Use a reference track or 2 right in the session.. always go back to it ..especially if you use headphones.. you will more than likely find that you are "Overmixing" based on your memory of what something sounded like, verses an at your fingertips immediate sonic comparison.   You might remember the bass from a song at a club... or the guitar from the song at the supermarket..etc...  you need to hear what inspiration you are drawing from right there in your mix... in your session.  Also - you'll spend 99 cents and support another artist just like you~

Sometimes the best way to boost the treble is to cut the bass. That's what a simple tone control does. I think your solution of finding an EQ set up for your final export will work well and cost nothing. Experimenting will cost time but no hard cash outlay. There are also EQ options in Cakes export program where you can manipulate the EQ.