2008年12月12日星期五

Bose headphones


Background

Acoustic Noise-Cancellation Development
The idea of personal noise protection by actively controlled headphones was originally documented in a 1960 Russian patent application. In the United States, the idea for active noise cancellation for helicopter and aircraft pilots was patented by Dr. Lawrence J. Fogel as early as the mid 1950s U.S. Patent 2,866,848 , U.S. Patent 2,920,138 , U.S. Patent 2,966,549 and Canadian patent 631,136. According to Bose, the company started noise-cancellation involvement after Dr. Amar Bose went on a 1978 flight to Europe, utilized the headphones provided during the flight only to conclude that he couldn't really enjoy the sound with the roar of engines in the background.".
In 1986, Bose applied their noise-cancellation technology to develop headphones to protect the hearing of pilots participating in the first non-stop around-the-world flight.
One source notes that "nearly simultaneously, the US company Bose and Sennheiser in Germany presented active headsets for aircraft pilots," citing a 1986 American Society of Mechanical Engineers paper about the Bose product and a 1988 Funkschau (see de:Funkschau) paper about the Sennheiser. Bose's first noise-cancelling headsets were released to the public in 1989.
After about 10 years of research and development Bose released their first consumer level noise reducing headphones for pilots called the Aviation Headset, released in 1989. The current revision provides active equalization as well as active noise reduction.
Like all such technology, it mixes an inverted sample of the ambient sound outside the headset with the sound that reaches the inside of the headset, partially cancelling out the noise. Active (battery-powered) noise cancellation is never perfect, and is better at low frequencies than at high frequencies.
As with all active noise cancellation technologies, it requires a source of power—a small battery inside the headset—to perform the cancellation.

Bose TriPort Earcup Structure
The "triport" earcup structure has three miniature air ducts that allow the drivers to make larger excursions without resulting in distortion. The design was first used in the Bose Aviation Headset X "Magellan" released in 1998 and is now used in all of the company's headphone products.
All Bose headphones are closed-air to provide passive noise reduction.
QuietComfort Headphones

Bose QuietComfort 2 Headphones "Second Edition"

The Bose QuietComfort 2 Second Edition was introduced August 2005. The earcup color was changed to silver, "acoustic equalization" was added, and the earcups now incorporate magnetic shielding.
The QC2 is powered by a single AAA battery inside the right earcup with a built-in attenuator. The cord can be detached at the user's discretion for stand-alone noise cancellation.
JAL provides Bose QuietComfort 2 Headphones for use by passengers in premium flight classes on some long-haul flights.
A cellphone adapter has been made available to users for the second edition and QC3 headphones.

Bose QuietComfort 3 Headphones

Bose released the QuietComfort 3 Acoustic Noise Cancelling Headphones on June 15, 2006, the company's first pair of supra-aural (on-the-ear) headphones.
Bose states that, although the supra-aural configuration provides less passive blocking than their circumaural headphones, the QC3s have the same amount of total noise reduction as the QC2s due to improved active noise cancellation. In 2006, they were the first headphones to receive a Sound & Vision Editor's Choice award.
The QC3 appears to achieve its active noise cancellation performance at the expense of stability of causing an unpleasant squealing noise as described on these following flaws:
Pressure on the earpads, such as that caused by the user leaning their head against a flat surface.
Manually pressing on the headphones.The QC3 uses memory foam to conform to the ear and provide a good acoustic seal without uncomfortable pressure.
The QC3's earcups are too small to contain a AAA battery, and are powered by a rechargeable lithium-ion battery instead. Bose claims a battery life of twenty hours, about half that of the QC2.
Bose QC3 headphones are provided by American Airlines for use by passengers in premium flight classes on some long-haul flights.On 11 January 2008, Engadget revealed that Bose was going to release a Bluetooth adapter for the QC3. No information was given on a QC2 Bluetooth version.

Bose TriPort Headphones

Bose Around-Ear (AE) Headphones

Introduced in 2002and originally called the TriPort headphones, they were renamed the Bose Around-Ear (AE) Headphones in October 2006. The Bose Around-Ear headphones don't have active noise cancellation (as opposed to the QuietComfort 2 headphones). For a short time, the Bose Around-Ear headphones were also sold with a Bose-badged CD player as a part of the company's "TriPort CD Music System".
A New York Times reviewer commented that "the research effort paid off: the [Bose Around-Ear Headphones] has very full sound and works equally well with all types of music," but judged a competitor's headset, priced at less than half the price of the AE's, to be "just as comfortable and just as light, and the sound it produced was just as full and clear."A few months after the release of the iPhone in 2007 Bose redesigned the AE's headphone jack to make it iPhone compatible

Bose On-Ear (OE) Headphones
The Bose On-Ear headphones were introduced on October 12, 2006. The Bose On-Ear is similar to the Bose QuietComfort 3 Headphones, but without active noise cancellation. The cord is detachable; both 43 and 16-inch cords are available.
Shortly after the release of the iPhone in 2007 Bose redesigned the OE's headphone jack on the detachable cords to make it iPhone compatible.

Bose In-Ear (IE) Headphones

The Bose In-Ear headphones were introduced on October 12, 2006 as the company's first earbud product. Three eartips of different sizes are included. Bose claims that the IE's silicone tips are shaped to fit the ear's natural curves more closely.

The TriPort airducts in this product consist of two air ducts in the large grille, and one "stand-alone" air duct on top of each earbud.
After customer complaints stating that the "silicone ear tips become detached under certain conditions" and that the "stability of the headphones during certain activities, such as exercise, could be improved", Bose setup a website to send redesigned ear tips and a new clip and the lanyard for free.

IE v2
On March 15th, 2007 Bose redesigned the headphones which fixed many of the issues with the silicone ear tip stability. The cord for the redesigned headphones is now black and white to signify the change.

IE v3
Shortly after the release of the iPhone, on October 11, 2007, Bose redesigned the IE's for a 3rd time. They made the headphone jack iPhone compatible and removed the circuit board from the headphone jack and moved it up the cord. Bose also included a clip and a lanyard on this revision as well.

Bose Aviation Headset X "Explorer"
The original Bose Aviation Headset X ("ten") was released in 1998. This was Bose's first product using "triport" technology, and according to Bose was lighter in weight, used less headband force, had better sound, and better noise reduction than Bose's previous aviation headset.
Aviation Headset X was voted #1 by Professional Pilot magazine's headset preference survey five years in a row from 2000 to 2005.
The July 2003 "Explorer" model added improvements in the "down cable" assembly (including the boom microphone and battery pack).
Bose offers an accessory for this model which allows the headphone to be permanently installed in the aircraft and eliminates the need for battery power, and offers trade-up programs for earlier models.

Combat Vehicle Crewman Headset
In 1993 Bose introduced an active noise reduction system for use by crews in United States Army armored vehicles.
At noise levels of 115dBA SPL, Bose noise cancelling headsets improves speech intelligibility scores to 95%, compared to 80% for conventional headsets.At low frequencies, Bose headsets are much more effective in attenuating noise than passive noise reduction headsets. A binaural talk-through feature allows crewmen to talk directly to each other without removing their headsets.
This product is not available to civilian consumers.

Bose QuietComfort and American Airlines
American Airlines provides QuietComfort 3 headphones to first- and business-class passengers on some long-haul flights. Bose has made American Airlines several special edition versions of the QuietComforts starting with the original QC1 that had blue ear cups and an American Airlines logo on them. American Airlines became the first airline to offer the QuietComforts.
American Airlines allows each of their First and Business Class passengers to use a pair of the QuietComfort 3 on long-haul flights to Europe, Asia, deep South America and select First Class transcontinental flights.
On 1 July 2006JAL started to offer QuietComfort 2 headphones to First class customers on some flights
Air-India also offers QuietComfort 3 headphones to its Premium Class customers on some long haul flights.

Awards
2000 to 2005 Aviation Headset X was voted #1 by Professional Pilot magazine's headset preference survey five years in a row.
2004 Red Dot Award for product design on QuietComfort 2
2006 QuietComfort 3 were the first headphones to receive a Sound & Vision Editor's Choice award.
2006 Potentials Magazine Gold Star Award] for the QuietComfort 3

2007 Red Dot Award for product design] on QuietComfort 3
Criticism
Critics have said:
The QuietComfort headphone models have a high price tag.
The QuietComfort headphones are incapable of unpowered operation, unlike some competitive products which operate passively, without noise reduction, when unpowered.
The QuietComfort 3 have "earcan" instability and has half the battery life of the QuietComfort 2.
Early versions of the TriPort headphones were fragile and subject to headband and earcup cracks.
in Late 2005 TriPort Headphones were re-designed to address these problems with a P3 label on the package. TriPorts are now called the Bose Around-Ear Headphones and have these improvements included.
Some complaints about the early production In-Ears have been that the "silicone ear tips become detached under certain conditions" and that the "stability of the headphones during certain activities, such as exercise, could be improved", Bose setup a website to send redesigned ear tips and a new clip and the lanyard for free.
The Bose in-ear headphones are only audio headphones and have no noise cancellation technology.

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