One thing I never really paid much attention to was the noise cancelling 2nd microphone on the back of the Nexus One. The idea is that while you are talking on calls, because it is facing away from the caller, it focuses on ambient noise and uses that information to cancel out the background noise when the voice is transmitted to the other side. I’m not exactly sure how well it works because I haven’t done any tests, yet but I ran across this video which did do some testing. In this CNET video, they test out a couple of different phones in noisy environments and play the results back. The differences are fairly remarkable:
And some first hand accounts of the noise cancellation features on the N1:
As a practical test tonight I made a call to a willing punter – my eldest lad – armed with the Nexus One handset and a Black and Decker hand jigsaw tool. I started the call as normal, speaking to the lad for a minute or so to allow his ear to acclimatise to the specific conditions (mine and his environment). This is a good control to ensure that there is no confusion as the test commences.
After a short while I started up the Black and Decker, the tiny tool is very noisy, probably well in excess of the 80Db safe levels (it does make the ears ring after a while). All the while I was continuing to speak in my normal voice and volume. He reported to me that he could hear the jigsaw but that it faded back as my voice took priority each time I started to speak again. When I stopped the jigsaw noise came back to its painfully loud level. Again, when I started speaking it rapidly faded into the background where my voice was heard by him completely clearly and plainly, no distortion or overpowering by the ambient noise. This is excellent.
As a final control I made another call to him in exactly the same environmental conditions, this time using my iPhone as typical of any modern day handset. This time the results were profoundly different.
At the start of the second call [using the iPhone] my voice was again heard very clearly. But it was when I started up the jigsaw that everything went completely wrong. He reported to me that my the jigsaw totally dominated the audio and, when I spoke, that my voice was unintelligible, distorted and breaking up such that he could not understand a single word.
Now, I know that this was an extreme test. But there is nothing better than performing such an extreme with this technology because it is designed to cope. It would therefore be up to the specific implementer, in this case HTC, as to whether or not the noise cancellation would be effective.
I am absolutely delighted to say that in the Google Nexus One that HTC have implemented its noise cancellation technology 100% effectively. The average user will probably not realise the benefit behind the technology until they make a call from inside a noisy club, pub, disco, roadside, train station, airport and any number of other situations that we all take for granted.
I never knew that the E72 had noise cancellation technology either. Something to keep in mind if you often make calls in noisy environments, nothing worse than having to keep repeating yourself!