The Bose QuietComfort 15, or QC15 and the QC3 are two of the most popular acoustic noise-cancelling headphones from Bose. The QC15 is powered by a AAA battery and has an around-the-ear design that provides better noise cancellation while the QC3 is an on-ear set of headphones that are powered by a rechargeable Lithium-ion battery. The QC15 retails for about $300 and the QuietComfort 3 is more expensive at $350.
QC15 headphones sit around the ear. They were based on the design of the QC2 Revision 2, but also have a microphone on the inside and outside of each cup. They can block out all external sound and are comfortable, as they completely encase the ear.
QC3 headphones are compact on-ear headphones that sit on top of the ear instead of enclosing it. They include pads made of memory phone that rest on the cartilage around the ear canal, forming a seal. Because they sit on top of the ear instead of around them, they have slightly poorer noise cancellation. However, they are also smaller and more portable.
QC3 headphones are lightweight and comfortable to wear for long periods due to the use of memory foam. Although a QC15 headphone encases the ear comfortably, it can create a mild pressure on the eardrums.
Both the QC3 and the QC15 require batteries to operate. The QC15 is powered by one AAA battery, with up to 35 hours of battery life. The earcups of the QC3 are powered by a rechargeable lithium-ion battery with up to 25 hours of battery life. The use of AAA batteries makes the QC15 slightly more convenient, especially because you don't have to carry the charger around when traveling.
edit Carrying case
Both headphones come with a carrying case, which is smaller for the QC3. The QC3 case also has room for an iPod but the QC15's case is larger yet lighter.
edit Sound Quality
Bose's QuietComfort 3 headphones have excellent sound quality. Although QC15 headphones are considered very effective at cancelling outside noise, they have poorer sound quality, especially for loud music.
Brand new QC3 headphones cost about $350 on Amazon but older models are available at a roughly 40% discount (see current QC3 prices and deals on Amazon). The QuietComfort 15 is relatively cheaper at $299 (or further discounted) on Amazon.
QC3 headphones were first released on June 15 2006. They were Bose’s first pair of on-ear headphones. The QC15 were released on August 20, 2009.
The Bose QuietComfort 3 received a Sound & Vision Editor’s Choice award and a Potentials Magazine Gold Star Award in 2006. In 2007, it won the Red Dot Award for product design.