Bose audio equipment is known for producing big sound. The Bose QuietComfort 15 acoustic noise-canceling headphones are the latest addition to the line of Bose noise-cancellation technology. While this headset is well designed and seemingly produces high-quality sound, when we asked for specifications about these headphones, we were told, "Bose does not publish specifications like frequency response for any of its products, because that type of information tends to be unreliable." We then asked for a test headset but did not receive one. Because of this lack of information, the QuietComfort 15 ranks lower than the other headphones we reviewed.

Because we weren't given any information on the performance of this audio accessory from Bose, we did some research on other sites and found tests that others had performed. They found that the frequency response did well with low tones but became erratic on the high end. Bose's site claims that the QuietComfort 15 has a "wider range of frequencies" than earlier models, but without actual numbers to compare, this is a difficult claim to substantiate.

One site recorded the Bose QuietComfort at a sensitivity of 112 decibels, which would be the highest sensitivity rating of any product on our noise-canceling headphone review. A number like this would mean crisp, clear sound and no static in the background. However, we also found a site listing the sensitivity as 101 decibels, which would be the lowest rating among the products we reviewed. Again, because of the lack of numerical information, we had to rank these headphones lower than products from other manufacturers that provide the specifications for their noise-canceling headphones.

In a number of other reviews, we found complaints that these noise-canceling headphones do not offer a passive play option. Once the AAA battery is dead, these headphones will stop working altogether. They have an operation time of 35 hours, so it will take some time before the battery runs out. However, a passive play option is preferable for people who don't carry spare batteries in their pockets.

The only real specifications listed for the Bose QuietComfort 15 are the dimensions. They measure 7.5 inches high by 6.5 inches wide. The ear cushions measure 3.75 inches high by 3 inches wide. They weigh 7.3 ounces. These headphones are slimmer and smaller than many other models, and this is appealing to those who don't want to look like an air traffic controller when they're listening to music.

The Bose site offers a variety of helpful tools for customer support. The QuietComfort 15 comes with a one-year warranty. There is also email and telephone support. While visiting the Bose site, a pop-up window offering online chat assistance will periodically appear. In addition, there is a FAQs page and an online manual you can download. However, despite all this support, the company will not provide you with specifications for its products.