Don't put background music on your website. If you want a professional website that has high traffic and retains visitors, it's a good rule of thumb to stick with. There are always rare exceptions (which I will list later), but for the most part, you should take this small tid-bit of wisdom to heart.
Here are the reasons why:
1. Credibility - There are certain hallmarks that newbie website builders cannot help but fall for. Background music on a website is one of them. Unless you're selling music or music services, having background music play on your website makes it seem unprofessional. This lowers your websites credibility, and thus you lose retentions of your visitors. People aren't visiting your website to listen to music... they are probably there to find information. Think about it... does Google, Yahoo, Newsweek, Sprint, or Amazon play music on their websites? Do any 'professional' or 'credible' websites you know of play music? Now think back to all the website that you know of that DO play background music... how credible did they look? Did most of them look like a first grader designed them? Did it look like a MySpace website? How credible are MySpace websites? Would you trust content on websites like these? Hmmmm.....
2. Bandwidth - Streaming a full version of a song (4-5 minutes) as a background music for your website takes up too many resources. That being said, if your website is super slow to load and 'choppy' to visitors with slower connections, I can pretty much guarantee you won't have a lot of returning visitors. Not to mention the fact that every time you refresh or load a new page, the song starts over - super annoying.
3. Repeating Music - Many people will play smaller segment of background music that loop so as to minimize load times to their websites. If anyone comes to your website and spends any amount of respectable time there, it won't take long before they go crazy listening to a 15-20 second long song segment loop a thousand times. If you 'play that funky music'... you're going to have visitors leaving your website in droves.
4. Taste In Music - Everyone has different tastes in music. What songs you like, others may detest. I know, I know, it's hard to believe not everyone loves Barry Manilow as much as you do, but the last thing you want to do is drive people away before they even look at your content.
5. Music Already Playing - Now days, people spend a lot of time on their computers. Because of this, they often have music playing from Cd's, MP3s, Internet radio, etc. on their computer to help pass the time. How annoying is it when you visit a website and it starts playing music that mixes in with your music? Nothing fun about trying to listen to two tracks at the same time. The quick fix will be to leave your website.
6. Public Computers - Nothing like being at work and hitting a website that all of a sudden starts blaring 'The Piña Colada Song' at 300 decibels. It's highly unlikely you will get many return visitors if half of them are out on the streets looking for a new jobs.
7. Legal Issues - Do you have the legal right to broadcast the song you want play as background music? If you don't, you might get away with it for a while, but if you plan on your website ever having any amount of significant traffic, be warned. The more popular your website, the more likely you will get noticed playing songs illegally. Litigation, fines, and law suites are no fun.
8. Browser Compatibility - Not every browser is capable of playing every type of music file. Having background music on your website comes with the risk that some of your users may have older browsers that lock up when the music is attempting to upload or play.
There always exceptions to every rule. Here are a few cases when playing background music would be considered acceptable.
1. Musicians And Bands - If you're a musician or in a band and are creating a website about your work, then it would only be reasonable to have some of your songs playing in the background.
2. Establishments And Events That Revolve Around Music - Dance clubs, bars, concerts, etc. Playing music might help set the mood of what to expect at your establishment or event.
3. Personal Websites - Personal websites are off the table. Express yourself freely with whatever song you like if this is what you wish to do.
If you feel its appropriate to play background music on your website, be sure to display PLAY, PAUSE, and VOLUME controls one your website in plain view so that people can have the option to turn it off or lower the volume. You might also consider not having any music play upon page load, but instead, offering the option for them to play it if they want to hear it.