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In Reply to: re: Bose should be discontinued. posted by David S. on May 27, 2016 at 09:44:44
They were invented by Audio Technica. Bose was just a marketer reseller. Id hate to see them get credit they don't deserve.
ET
Follow Ups:
The first Bose noise cancelling headphones were developed for the flight of the Rutan Model 76 Voyager, the first aircraft to fly around the world without stopping or refueling. The flight occurred in December, 1986. Bose noise cancelling headphones became commercially available in 1989.
Bose had Active noise headphones in the 90s. The patent you referenced has a priority date in 2008, so obviously, that AT patent is far behind and covers something different (or managed to reinvent the wheel without being caught)
- in mid 2000s, there were already ANC headphones on the market. At the time, I believe all of the consumer market headphones used simple feedback control. I had a pair of Sennheiser PXC circa 2004. Feedback control for headphones is relatively simple to implement, it can be all analog. For a prop airplane, one can do feedforward easily (the bpf is easily known and can be used as reference)
- my understanding is Bose was never Enthusiastic of feedback control, the later consumer models are feedforward control. Feedforward is far more difficult to put together, especially sinc there's almost no space to work with in headphones (space is equal to time, handy when you have delays in your control loops, or conversions)
- looking only at the artwork, the AT patent you list seem to be some sort of feedforward control without an error sensor . That's feasible (virtual sensor) but requires some assumptions or predefined/measured) transfer functions.
Finally, i have yet to hear headphones with a better active attenuation than Bose's. I am not talking music, just ANC performance, and that's a measurable quantity. I use QC20s.
Doh, I stand corrected. The phase camcellation used in hearing aids works like thos and its all on a small chip. Its been around almost as long. What is critical on both is the placement of the mic that will send the noise portion that needs to be cancelled by it being in reversed phase.
ET
Yeah, and AT's version cost less and worked better. People where I worked (we had to travel a lot by air) stopped asking for the Bose and changed to the AT's after they heard them.
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