I'm still learning, I'm curious to know what more experienced people do to clean the low end of their mixes up.
So the bass doesn't sound distorted and dirty.
 
I had an issue with a bass guitar and a kick drum not going well together and I tried to EQ them together with no real luck. In the end I found that sidechaining a compressor and ducking the kick drum when the bass plays was the best solution, with some EQ to tighten up the sound.
 
Any methods you all use in particular to have a clean sounding low end?

http://therecordingrevolution.com/2010/07/26/the-fastest-way-to-clean-up-your-mix/

Uh, capture is the most important part.  Capture a good definition of both instruments and mixing them gets a lot easier.  That means good instruments, good players in an ok room w/ good recording technology.  I'm not talking Abbey Road, but basic stuff.  Oh, and well arranged parts so the kick and bass aren't stepping all over one another.  Get that right, and most of the problems of a muddy low end become manageable. 
 
Next, ruthlessly high-pass all the tracks.  If you typically have 16 acoustic tracks that means a lot of low level noise in the bass frequencies building up.  And few instruments have a fundamental under 100 Hz - bass, kick, floor tom, piano and such.  Go through all your channels and get rid of the moving air on all of them that don't need low end.  You'll find many can go up to 200 Hz or higher w/o touching any meat of the respective sound.  Do that and you'll get rid of tons of build up in the bass frequencies.
 
Then start using complementary EQ on the Bass and Kick, ducking and all the other tricks.  That is a final polish more than getting rid of the problem.
 
@

And in some cases, don't even be afraid to lose some of the "meat" of a sound by high passing it. When you listen to a good busy mix closely, it becomes obvious that some of the instruments would sound very thin and weedy if soloed. But in the context of a busy mix it doesn't matter because more prominent parts are supplying the beef. For instance if you have an acoustic strumming part that's not a major part of the arrangement then sometimes you can high pass all the meat out of it until all you can hear is the percussive pick sound. It sounds terrible soloed, but in the context of the mix it adds a great rhythmic element to the track without adding any additional mud. 

High pass is good as stated above. You might have better luck ducking the bass when the kick drum plays, can't see how the other way round would work.

AT
Uh, capture is the most important part.

I should clarify that both recordings were given to me as part of a class where the lesson was to use EQ to make 2 instruments occupying the same frequency play well together. I agree with you 100%. A good recording should lay the foundation for any good song. You have to do your best at every stage of production to make the best song possible.
 

wizard71
High pass is good as stated above. You might have better luck ducking the bass when the kick drum plays, can't see how the other way round would work.

 
Do you think it depends on the song which one you would duck? in this song it seems the bass guitar is 2nd to the lead melody (sorry I'm not good with music terminology yet) and it seems like the kick drum is only backing it up and driving the rhythm of the song. I got it ducked by about 3-6db when the bass guitar plays. This song has a real 1950s vibe to it.

also, 
study the wav file EQ's of some of your favorite pro recordings..
you'll need some kind of 3rd party program to do this (SPAN is free, for example)
 
 
case in point:
here is the waveform for one of the latest QUEENS OF THE STONE AGE tunes, called 'My God is the Sun"
 
 
mostly look at the GREEN lines, this is the average peak energy at the frequency shown.
 
look at what happens at 100hz and below...
look at 150hz....
look at 200hz
look at 300hz
and what the h#ll is up with 3khz?!
 
LOL
 
every mix will have different reasons why certain freqs are boosted and cut...
your job, is to study all of your tracks individually, and figure out what is going on with them...
if you have buildup, you have to tame it.
 
 
as said earlier, most of these issues should be dealt with during the CAPTURE...
and only time and experience gets you there.
 
 

If you duck the kick, you are lowering the kick whenever the bass plays. Most often, the bass is always playing when the kick hits, so you really don't want to lower the kick. Ducking the bass is the correct way so the kick hits are at a consistent level. However, make sure the release time is low so the bass doesn't sound like it is dropping out. You only want the initial kick transient to come though the bass.
 
Regards,
Dan

you know, they NEVER ducked' john bonhams' kick.
 

Watch the bass mud, HP filter anything that doesn't have useful content below whatever. Watch out for too much 160 (eww nasty), dropping 160 really cleans up pianos especially when they hammer lower octaves. Everything has it's place in the mix and everyone has an opinion, listen to producers who get the sound you like. Google musical ranges of instruments, great info and definitely worth checking out. Give everything its own little slot in the spectrum, especially if you want detail. In the end, trust your ears, it's your mix. Remember, it doesn't matter if you break someone's rules if it sounds good, the rules are only there to give you a reference point. Ducking the bass with the kick adds punch, an 1/8th note ducker gives a ska feel if pushed to extremes, use a faster slope and less compression if you don't want it to be noticeable. Sometimes guitars sound better in the mix when they're thinner than you think they should be.
 
Oh yeah, you might want the kick higher than the bass, boosting 100 Hz gives you a lot more chest thumping for kick, 40-80 rattles the walls better for bass. Don't neglect the top though, it gives both instruments definition. If you want hip-hop, add a sine to the kick. :)