What are headphones? Simple answer? They basically comprise a pair of transducers that receive the audio signal from whatever music device they're connected to and convert those signals into sound waves to make the music and sounds we enjoy so much.

Some factors to consider:

1. Open backing... Will not usually give good sound quality due to the surrounding disturbances (outside noise).

2. Closed backing... blocks outside noise better than the open backed ones.

...from the phone, to the computer to the iPod and everything in between. These versatile devices improves our lives with the many great uses they do for you and I. From giving us mobility and privacy, as well as being compatible with computers to enjoy our video games with great sound.

Here are the main basic types:

1. Circumaural... these are big and cover your ears. Examples: Sennheiser 695, Ultrasone Proline 750, AKG K701. These are normally considered to be the "best" of the "best in sound. They are the largest physically so not well suited to carrying with your Ipod, but also provide the highest sound quality.

2. Supra aural... these go on top of your ears. Examples: Sennheiser PXC300, Koss Porta Pro, Sennheiser PXC250. Somewhat smaller size than the circumaural. Many times this design is used in noise cancelling headphones.

3. Canalphones... these go inside the ear canals and because they block outside noise are called passive noise reducing earphones. Examples: Ultimate Ears Super FI5, Shure E5C, Etymotic Research ER-4.

Compact and portable with very good sound quality.

4. Earbuds...are the main type that normally come with iPods. They go in the outer ear and sort of just hang there. Normally considered the poorest quality and most dangerous to a person's hearing.

Why? Because they don't block any outside noise. So, to hear them properly the volume is usually turned up to dangerous hearing levels. Usually average to poor sound quality.

5. Bluetooth...using Bluetooth technology. These wireless devices operate over a short-range and function without any cords or cables. They provide excellent service within a particular range, usually about 9 feet. Bluetooth headphones sport the latest in technology. Connections are automatic and the devices are simple and have no confusing workings. You can also change the settings for accepted and denied connectivity. Although Bluetooth headphones get its name from the respective technology, essentially the name is from the tenth century King of Denmark- Harald Bluetooth.

6. Waterproof...these are mainly ear canal type of earphones that allow the listener to listen to their favorite music or sounds...submerged underwater. The earpiece itself is waterproof, besides being in the ear and preventing water from entering. Of course, the Ipod, or other player has to be enclosed in a waterproof case or container also.

Remember, try to get the best headphone you can afford. Not only will get better listening enjoyment, the better headphones can actually protect your hearing more than the cheaper quality (means more volume) sound devices.