Where does the music come from in reality television?
Many of your favorite television music tracks come from popular libraries, such as the theme song from Curb Your Enthusiasm. And much of the music from It's Always Sunny In Philadelphia, also including their theme song.
Production music libraries are a popular source of music for television for several reasons. The chief advantage is that they are designed to be easy to license. The production company pays a flat fee to use music from a particular production library, and for that fee they are allowed to use all of that music in perpetuity, anywhere around the world that the show may be broadcast, on any platform or format even if it hasn't been invented yet. If you know anything about the nightmare of licensing music under these situations, you begin to see why using a production library is a good, no-hassle way to get music for your production.
Additionally, production music libraries are much cheaper than licensing commercial music or hiring a composer to write original music for your production. This is particularly true if your company is making several shows and can cut an overall deal with one production library.
There are many libraries available for you to investigate before deciding which one is right for your project.
My personal favorite is the Extreme Music library. This is a vast, vast library with every style and combination of styles you can imagine. I love that it has a large collection of classical music, as I tend to use it whenever I can (it's good for comedy, action, drama, everything if you know what you're looking for...) I love that they are constantly adding new stuff. The website is very easy to navigate and search for different tracks by feel or description or instrument or keyword or whatever! I've never had to struggle to find something in this library, and I always get exactly what I'm looking for after a little searching. I would use the Director's Cut series to score a film, should I ever get the chance.
The library I've worked with the most as an editor is called iSpy. This library has a lot more of what you would think of as typical reality music and I find is particularly suited for comedy and action, though it is used in all types of shows.
There are plenty of libraries out there, and here are some I have occasionally come across in my professional life:
Killer Tracks is a very popular library.
So is Vanacore
Lovecat Music has a lot of pop music with lyrics. I used it on Plain Jane for the CW.
Discovery Music Source is used by all the Discovery family of networks, such as TLC and Discovery Science.
Audionetwork is a British company that is gaining footholds in the US.
The downside to using a production library is that none of the tracks will be truly unique to your show, and there is a risk that viewers will begin to recognize or even tire of the music. I find this is generally a small risk, and one well worth taking.
Here are some more libraries I have worked with now, on MTV and other networks:
Beach Street Music
Black Toast Music
In The Groove
Pfilbryte - I particularly like this library for quirky and docu stuff
AudioSparx - Easy licensing for independent filmmakers