The JimH Blog

Noise Canceling Headphones

On a recent long airplane trip, I sat next to a guy who seemed a little more relaxed than those around him. He was wearing headphones, but rather than tapping his feet or swaying to the music, he was just comfortably resting. A closer look showed the headphones weren’t plugged in to any sound source!

Eventually we started chatting and he told me his secret. He was wearing Bose Noise Canceling Headphones. He let me try them on. I put them over my ears. This alone helped quell some of the sound. Then he flicked a switch. At first nothing happened, but then after a few seconds the floor dropped out of the noise level. I hadn’t noticed how loud the engines were, but now that they were vastly attenuated I couldn’t believe that I could even keep my sanity with such a racket.

The headphones aren’t magic. It’s not like I was in silence, but it was the difference between an emerging headache and feeling suddenly at ease. Amazing.

Geeks will know that the secret is tiny microphones in each ear cup that feed a signal to a microprocessor which then adds an opposite phase cancellation signal to whatever the music source provides. To do it completely in real time is an impossible physics and computational problem even before you add in all the extra psycho-acoustic corrections, but the imperfect approximation was a major advantage.

Before my next long airplane trip I stopped by a music store but they didn’t carry the Bose model. I ended up with a pair of Sony in-ear plugs. Trying them at home was disappointing. If there isn’t a lot of ambient noise to cancel out, the circuitry can actually make the noise level worse. (The phones have an on/off switch for this reason.) Even on the plane it took a while to get it working right. I had to jam the plugs further into my ears than seemed right, but once they were properly situated, the magic happened again.

Here’s the big difference. On my first airplane trip with normal headphones, I could easily listen to audio books on my iPod, but music was tough, especially if there was large dynamic range as with jazz or classical. On my second trip, I could enjoy a cello concerto or a jazz vocalist as easily as I could listen to my eclectic collection of pop songs. From now on, I won’t fly without them.

Why stop at canceling sound waves, though? I can just imagine teams of Japanese engineers hunkering over their lab benches working on ways to cancel light waves, tsunamis, or life regrets. What a product that will be! Batteries not included.

The view from Space

I'm totally obsessed by the satellite image technology from keyhole.com. They have collected enough images to cover the planet (well, the planets, Earth and Mars) and have more-or-less seamlessly stitched them together so it looks contiguous. Then you get to zoom in on the location of your choice, and adjust your tilt angle to get the view you want.

Better than that, if you select a series of locations, you can smoothly fly from one to another.  Short hops feel like you’re in a helicopter. Longer hops feel like you’ve been abducted by aliens and are seeing the world from the perspective of a high-speed UFO.

Here are some images. See this photo album for slightly larger images, or click the thumbnails below for even bigger ones. Make sure you expand them to full size to see the most detail.

Here’s where I work.

This view of my office shows the tilt function. You can see Mt. Rainier in the background. The software knows something about elevations. Not every building is 3-D but the basic terrain rises and falls correctly and then the satellite photo is textured on. The reason it looks a bit like a video game is that video games use the same technique.

Sometimes this works better than others. The tilt on this image is from the wrong angle relative to what the satellite actually saw, so the buildings look strangely artificial.  For most of my career, I worked in one or another of the six X-shaped buildings on the right.

Sometimes the tilt views are very convincing. This shot of Port Townsend doesn’t look as artificial.

This image of my old neighborhood in Vancouver shows the view I might have had from a non-existent 100-story building behind my house.

What I can’t show you in this blog is the incredibly smooth animation. If you have a fast machine and a high-end nVidia card, it’s truly amazing.

FreeCell and the power of the Internet

Some computational problems can be efficiently solved through massive multiprocessing; thousands of CPUs working together to provide a solution. Sometimes those CPUs can be human brains. As so often happens in life, FreeCell provides a nice example.

Years ago I wrote a sentence for the FreeCell help file that said "It is believed (although not proven) that every game is winnable." This was carefully worded because, it turns out, it's fairly easy to construct FreeCell shuffles that can’t be won. Enter game number negative one or negative two for examples.

What I didn’t know at the time was whether any of the 32,000 shuffles provided with Microsoft FreeCell were unwinnable. Certainly most of them could be beaten, if not by me then by my colleague Greg Jones. I thought about trying to prove it by writing a game solver and pointing it at all 32,000 games, but I already had a game solver -- my brain. It was just too slow.

Way back in 1995 when the Internet was already established but not quite mainstream, a chap named Dave Ring started the Internet FreeCell Project. If you wanted to participate, you let him know and he sent you a list of 100 or so game numbers. Your job was to report back which ones you beat and which ones stumped you. The ones you couldn't win got thrown back into the pot to be doled out to somebody else. Eventually the games got harder and harder and soon there was only one which nobody could beat, the famous number 11,982. What a great example of the power of the Internet.

Definitive proof that this game was impossible came soon after through traditional computational methods, but humans found the answer first and along the way did something computers couldn't. They had fun.

Sorry about that, Chief

There was a comment recently on this blog about exactly how the original Microsoft Pocket PC worked in the cell phones of the time. Here's an old pic of me testing an early prototype:

What's the buzz?

There's a lot of buzz about this new Audiovox cell phone. Is it worth the $200? Should I scoop it up now or wait for the inevitable next generation which will include Tealtooth and a built-in DVD burner?

To me it's not about the technology. Click on the ad photo on the right to expand it and take a close look. You've got your application icons, your date and your time, but look just below that. It's the Outlook calendar. Note the magic words: "No upcoming appointments."

That I'd pay extra for. Sign me up.

HP screws up its iPAQ 4700

I've been an iPAQ fan through several product versions, but I feel totally ripped off spending $650 on the latest model, the HP iPAQ 4700. (Of course I used my income from selling DVDs to pay for it!) It's too expensive. The screen is big and beautiful but the surrounding case is too bulky. Those are forgivable sins, though, compared to the major industrial design failing.

Instead of a nice leather case to slide the Pocket PC into, it has a hard translucent flip cover that opens from the left side. The idea is that you fold it behind the device while you poke away at the screen with your plastic pencil. Only one problem. It’s so uncomfortable that after a few minutes you lose all feeling in your left hand and after a few more minutes the feeling returns in the form of discomfort and then major discomfort and then pain. It’s a disaster. Buy something else.