Bass management problems include trying to get your CD player to use your sub, or having way too much bass coming out of your dainty rear speakers when you use DVD-Audio or SACD driving them to Hades.

If your main media player is a DVD player, be sure it’s set to bitstream and not PCM if you want the use of the rear speakers and sub.  At least be aware of where this is set and get to know it well.  For greater audio fidelity some like to set PCM when listening to two channel sources, it ensures an uncompressed listening experience, but will often do without some of the effects you demand when watching DVD movies. 

There are many differences between bitstream and PCM, usually DVD players are capable of both but CD players are generally only capable of PCM.  Without delving into bit and sampling rates the short of it is that Dolby Digital and DTS both sample at higher bit and sample rates (than PCM) but then they compress it, which is a sin to the audio purist.  PCM is a slightly lower bit/sample rate but uncompressed.  DTS uses less compression than Dolby Digital and that's why it's usually considered superior. 

To use my favorite analogy FOOD:  PCM is a good diner that serves beer.  The PCM waitress brings a steaming plate of delicious food and a cold beer.  Nothing fancy but it does its job.  That's PCM.

Bitstream is if went to a really fancy restaurant, and they bring this amazing culinary delicacy to your table.  But before you can eat it, the waiter picks up the food from each dish and grinds it together with his bare hands letting the pieces fall back onto your plate.  Then he bids you bon apitite as he walks away.  That's bitstream.

What does this mean to you ask?  Part of what makes "bitstream" so fancy and certainly a MUST HAVE on your DVD player, is that bitstream audio encoding methods like DD and DTS aren’t just raw music, but carry encoded instructions along with the audio.  Commands for when the sub should kick in and when rear speakers should be used are included.  PCM is just two channel music, it can only “tell” left speaker/right speaker what to do and when to do it just like stereo has been doing for decades.  It’s “pure” but there’s no fancy surrounds or sub being commanded explicitly (discreetly) by the audio signal.

That said, one would expect to get no sub or rear speaker action when listening to two channel PCM CDs.  That’s not necessarily true thanks to Dolby ProLogic, Pro Logic II, DTS neo-6 and other methods of creating a multi-channel “matrix” from two channel information.  If you notice your rear speakers kicking in while listening to CDs it’s probably has Pro Logic II enabled.  This brings us back to bass management. 

The typical Home Theater receiver bass management setting is the small speaker/large speaker settings.  The DVD player might also have the same setting.  With small speaker enabled, you’re setting a crossover, or a crossover frequency, that’s the frequency cutoff to the speaker you’ve set to small.  Sounds equal to or less than the crossover frequency will be redirected to the subwoofer.  You should only choose one component to handle the bass management, two components setting a crossover will likely cause you to lose some of your bass.  Read your documentation to see which component actually publishes their small speaker crossover frequency and then decide which you want to use. 

Set your front (main) speakers to “small”.  The small speaker setting is admittedly an ambiguous bass management setting but it’s very common on low to middle end quality.  High end bass management systems will allow you to set the crossover frequency.  On the ambiguous “small speaker” setting a typical crossover is 100hz.  That means all parts of the music that are 100hz or lower go to the sub.  If the fronts are set to “large” 100hz and less are going to the fronts and nowhere else.

You might have some fine front speakers you’re particularly proud of and would feel ashamed to call them small.  But remember, we’re talking about speakers here, not condoms.  That 100hz might be replicable by your front speakers, but even big high end fronts can’t reproduce those low freq’s at volumes your sub can.  Many bookshelf speakers are rated to 40Hz… SCHYEA!  If you look at the freq range of most speakers mapped out on a graph you’ll see that db tails off significantly in the low end. 

There are third party solutions for bass management.  One of the most popular is the Grand Moff Tarkin of bass management utilities called the Outlaw ICBM.  This baby allows you to set explicit crossovers to all speakers in your room.  It’s the “ultimate” in bass management.  If your receiver is light in the bass management department, and you want the high end way to control bass in your system but don’t want to spend high end money, a dedicated bass management component like Outlaw’s ICBM is the way to go.