Noise Cancelling and Motorcycle Pants

We went for a ride using our Scala Rider Q2 intercomm, and it just was not working right.  Sometimes the problem is in understanding how these things work, so I looked up the theory behind the "Noise cancelling" microphone.

I was having trouble hearing Mary Ann.  Sometimes her voice did not even activate the communication, and I had to push the mc button, but even then I heard almost no sound at the other end.  This is what I found out about noise cancellation.  First, was a very interesting video demonstration of a Scala Rider headset communicating through a phone.

http://www.engadget.com/2010/03/24/cardo-scala-rider-g4-headset-review-advanced-noise-cancellation/

If you listen on the phone, it is shocking that you hear absolutely no other sound than the rider's voice, even while he is riding a motorcycle on the highway at speed.  I was surprised, because I always used my headset while I was also riding, so with all the real road noise around, I could not notice that there was no noise coming through the speakers from the other bike's microphone.

How does noise cancellation work?  This not just a directional microphone, instead it has some electronic trickery to virtually "erase" the background noise.  A directional mike boosts the sound in one direction, and partially blocks it from other directions.  So with a directional mike, you point it at your mouth, and it should work, especially if you yell louder.  But like I said, this is not a directional mike.  The microphone cancels noise, but how can it tell what is noise and what is not noise?

Electronic noise cancellation does not work by recognizing human speech patterns, instead it is actually a fairly simple trick.  There are two microphones, one in front (toward the mouth) and one in the back of the boom.  The back microphone picks up background noise, and by way of explanation, anything the back microphone picks up is deemed background noise.  Whether you would classify it as  background noise or not makes no difference. The "background noise" (whatever the back microphone hears) is inverted and combined into the sound in the front microphone, entirely eliminating those sounds, (and only those sounds) whatever they might be.

To make a noise cancelling microphone work right, the trick is to make absolutely sure your voice is not being picked up by the back microphone.  So you should avoid yelling, for example, as this may flag your voice as noise.  The critical step is to position the microphone correctly.  The Scala Rider manual unfortunately is not clear on the exact position of the microphone.  It seems like you should place it very close in front of your mouth, centred horizontally.  Apparently you can move it from side to side without losing the sound, but you cannot move it up or down or your voice will end up as noise, and be cancelled.  In some places, Scala Rider suggests that the right spot is the corner of your mouth, in another it says centred on your mouth.

This is mentioned in the guide, but must be stressed.  Don't bother testing the the intercom inside the house or in a quiet place.  It seems to need at minimum, the sound of a motorcycle exhaust nearby to work properly. I don't really understand why, but here is an example.  Mary Ann and I both put on our helmets, and turn on the intercom.  Then we continue loading up the bikes, and closing the garage doors, during which time we can talk but the Scala Rider is not picking it up.  Then Mary Ann fires up Burgie, and I do the same on the Vulcan.  Mary Ann lowers her visor, then suddenly I hear the click of  her face visor shutting through  my speaker, and from then on we can communicate via Scala Rider Q2.  I have no theory about this, except maybe it needs some real noise to tell the difference between noise and speech??

So when I looked at Mary Ann's helmet, I noticed the microphone has slipped down, away from her mouth to the bottom of the chin bar.  When I move it back up, the system works perfectly.  Without noise cancellation, the sound quality would be awfully bad, but as with any new technology, you need to understand the principle behind it.  Maybe they should start teaching this stuff in school, or do they do that already?

Update on the choice of jacket and pants for the trip out west.  Now that I know how to clean the Scorpion Commander high visibility textile jacket, I will take it along, and leave my black leather jacket at home.  Helping me to make up my mind, Mary Ann is has now got a pair of textile motorcycle pants, the Olympia Airglide 3.  These "overpants" have large mesh panels for cooling, and can be worn over ordinary jeans or even shorts while providing an acceptable amount of protection in hot weather.  They can also be removed easily with full length zippers for walking around in your summer clothes.  I almost feel like getting a pair myself, but they are over $200, so I'll just go with my kevlar cargo pants.  While Mary Ann was trying on the silver coloured pants, she also tried on the silver coloured matching jacket.  With that combination she remarked that she looked like an alien from outer space.  So I guess she must have seen a few science fiction movies after all.  Anyway, women are often very influenced by what clothing is flattering, and Mary Ann did not think that looking like an alien from outer space was a good thing, so she didn't buy the jacket.  But I wonder about the hip padding, because most women do not want pants that come equipped with their very own set of padded hips.

Picture: Olympia Air Glide 3 ladies pants worn by a professional clothes model.  And she probably has the hip padding removed.