Noise Cancellation?

[Jarrod Roberson]

The way the Jawbone works is the best noise canceling technique for speech I have ever used.

When they say "military grade" they mean it!

I can talk on my Jawbone in my convertible with the top down at 85MPH on the interstate highway and people never know that I am driving down the road with the top down!

With most other noise-blanking headsets, there’s a distinct difference in the quality of the speaker’s voice when the feature is turned on, there isn't any difference in the quality of your voice with the Jawbone.

The Jawbone does this well because it has a sensor on the underside of the device that touches your face. When you speak, this Voice Activity Sensor can tell, using the resulting vibration to separate your speech from noise around you. According to Aliph’s marketing materials, this technology was originally developed for use in the military.

My Jawbone 2 worked great, and my ERA seems to work even better.

[TMM]

The closest you can get is those "noise cancelling" headphones/earbuds.  Even they don't use simple inversion.

Oh? i thought most of them did work by simply inverting the signal from a mic that is exposed to the outside and then playing it through the speaker/driver. The operating distance is small enough (a couple cm) that they have reasonable attenuation from low frequencies up to a couple KHz. Above this there would be a lowpass filter in order to prevent adding positive feedback to the noise as the wavelengths approach the path length difference of the mic, speaker, noise sources to the listener/ear. High frequencies have good passive attenuation from the closed ear cups so it's not really too much of a limitation.

There would obviously need to be some equalisation to the signal to compensate for the frequency response of the mic and the driver and achieve the best attenuation. Most mic capsules and small headphone drivers are well behaved up to a few KHz anyway.

[Richard Crowley]

The Jawbone does this well because it has a sensor on the underside of the device that touches your face. When you speak, this Voice Activity Sensor can tell, using the resulting vibration to separate your speech from noise around you. According to Aliph’s marketing materials, this technology was originally developed for use in the military.

In other words, it uses a figure-8 microphone. Sound entering from the BACK of the microphone capsule is "subtracted" from the sound entering from the FRONT. See Dave's microphone 101 episode on patterns.  This is how all noise-cancelling microphones operate.

[IanB]

At a single frequency, inversion and 180 degree phase shift is, in fact, exactly the same thing.

That's a special case that's not true in general.

In general, phase shift and phase inversion are different operations. It's a good idea not to use the term for one when you mean the other.

[Jarrod Roberson]

The Jawbone does this well because it has a sensor on the underside of the device that touches your face. When you speak, this Voice Activity Sensor can tell, using the resulting vibration to separate your speech from noise around you. According to Aliph’s marketing materials, this technology was originally developed for use in the military.

In other words, it uses a figure-8 microphone. Sound entering from the BACK of the microphone capsule is "subtracted" from the sound entering from the FRONT. See Dave's microphone 101 episode on patterns.  This is how all noise-cancelling microphones operate.

No it doesn't, it only has a single microphone. Which is not "how all noise-cancelling microphones work".

It has a vibration sensor ( a little silicon nub ) that reads the vibration on your skin from your voice to include only what matches the vibration.

Completely different approach to dual microphone solutions, which don't work worth a flip on battlefield level noises. Or convertibles at highway speeds.

[Richard Crowley]

A "figure-8" microphone IS a "single microphone".  Perhaps you should view the recent videos on Microphone 101.
They even mention SPECIFICALLY this application (microphone on a telephone headset, and went into some detail about how it works. Recommended.

You seem to be talking about a "throat mic" where they strap a transducer around your neck to pick up vibrations from your vocal cords.

[Jarrod Roberson]

Aliph uses a patented transducer based system. It is not this figure 8 thing that everyone else does. The results are in a class of their own. I have had both non-noise canceling and "typical" noise canceling headsets, the Aliph Jawbone sets are completely different in results. Nothing compares and most people don't even "get it" until they use one.

http://www.google.com/patents/US8340309 - Recommended

an acoustic vibration sensor in the housing, the acoustic vibration sensor comprising, a protrusion that extends from the housing to contact a skin surface of the user, wherein the acoustic vibration sensor detects human tissue vibration associated with near-end speech of the user, wherein the acoustic vibration sensor comprises a diaphragm positioned adjacent a first port and a second port of the housing;
a noise suppression system executing on a processor in the housing, the processor coupled to and using signals from the microphone array and the acoustic vibration sensor to separately identify voiced speech and unvoiced speech of the acoustic signals and denoise the acoustic signals; and