Wednesday, January 13, 2010

A Matter of Perspective

For those of you not familiar with Michigan, we are a state with lots of penninsula. A couple of weeks ago, I made the trek from southern Michigan "up north" to do some snow testing. We go way up in the Upper Penninsula, the UP, near the town of Houghton (upper left of the map). Its about a 600 mile winter drive crossing the Mackinaw Bridge between the Lower and Upper Penninsula.

As the Mackinaw Bridge is quite a landmark, you feel like you've made some real progress when you cross it. After all, you are almost half way. This shot of the bridge is a borrowed shot from another year. The foreground in this photo is ice, not land or water, and is more typical of the conditions we see in winter.

This year was strange, in that the cold weather came late and there was little ice on the big lakes in January. The shot below is of Lake Michigan from the UP side. As you can see, lots of clouds, but not much ice.

The people that live in the UP are called "uppers" or "yoopers". They call those of us who live in the lower penninsula "trolls" because we live "under the bridge".

The town of Houghton and the whole Keewanaw Penninsula are an interesting place. There is a lot of history to see, but the town itself is lively with a great sense of community. I like this shot of the old Miners Gazette building. Especially the way the stair rail to the door follows the border of the sign.

This shot is across the Portage River to some of the ruins of mining buildings in Hancock.

Actually, there is another bridge, the one between Houghton and Hancock. You see, the Keewanaw Penninsula is divided north from south by the Portage River. The Lift Bridge over the Portage is the only way to drive from the northern part to the southern part of the Keewanaw.

We cross this bridge every day to go up to the Keewanaw Research Center where we do our testing.

Last fall, one of my colleagues was up doing some testing at KRC and he invited one of the KRC workers to dinner down in Houghton. The response was something like, "No thanks. I don't like going down there. Nothing good every happens south of the bridge." Of course, he meant the Portage River Lift Bridge, not the Mackinaw Bridge. I guess, as a true yooper, he felt everyone in Houghton was a troll too.

As implied by the title, its all a matter of perspective.

Friday, January 8, 2010

A Little Loudspeaker Project

I really enjoy loudspeaker projects. In designing loudspeakers, you can never know it all. You need a mix of physics, electrical and mechanical engineering, and esoteric things like psycho-acoustics. You have to think about how our brain formulates an image of a sound, how it locates it and decides that its true or false. You also have to think about what in our hunter-gatherer past may have influenced how we hear and how the physics of a twig cracking in the forest may influence our perception of music reproduced by loudspeakers in a room. Mind twisting stuff.

Anyway, I don't allow myself to get too wrapped up in these ideas and build more speaker projects. After all, how many speakers do you need to build for yourself? Once you've got one or more good sounding speaker systems, aren't you kind of done? Or at least should be spending your time on other projects that lie neglected?

That's what I tell myself to stay away from speakers until someone comes to me and asks for help building speakers for themselves. In this case, that someone is Dan Schillinger from work and he has an interesting twist on the whole project. He came to me and asked if it would be possible to build some speakers into some wooden cigar boxes that he has.

He brought them in, we measured them up, and it worked out that we could build an nice little satellite with a 1" tweeter and a 4" woofer in his cigar boxes. The cigars are Remi "Acid" brand and the specific style is Kuba Kuba. The boxes are nicely made and finished, although we did need to reinforce the box on the inside. I can say one thing, they definitely retain the smell of the cigars that were stored inside and these are the best smelling speaker boxes I've ever worked on.

Of course, a 4" woofer isn't going to go very deep into bass or play very loud at low frequency, so we needed a subwoofer. I found a good deal on the Tymphany LAT 250. This is a very unusual speaker that has 6 "speaker cones" driven by two motors, one on either end and connected by metal rods. The "cones" squeeze the air between them and the sound comes out the slots in the face. For just $25, we had to give it a try.

Naturally, Dan came up with an unusual and neat enclosure. In this case, it is an old ammo box that we reinforced on the inside. Note the hand shaved boards and the fantastic old patina on the wood, hinges, and clasps.

Overall, the project is coming together very nicely. The attached graph shows the frequency response of one of the satellites. A fair bit of time goes into designing a crossover that takes into account the frequency response and impedance of the speakers, but the result is very satisfying.

Of course, the project doesn't answer any of those big, theoretical questions. Its a fairly straight forward design using inexpensive components and unusual enclosures. But overall it will be a nice little system and I hope Dan will enjoy it for years.

Friday, January 1, 2010

Bumper Cars

A little whimsy for the start of the new year. May we all have more reasons to smile in 2010. Make sure you read the license plates.

A gent in California decided build these babies, powered by motorcycle engines, to extend the life of these classic bumper cars.

As some of the license plates proclaim, all of these are legal and licensed in California. As a person with some experience with this topic, I can tell you that can't have been easy. I wonder what emissions rules he had to meet?

Thanks to Corena for sending along these pics. She is always finding interesting things on the web. I'd love to see what kind of blog she would write.

The theoretical top speed of these bumper cars is calculated at more than 160 mph. I'm guessing nobody has tried to confirm it.

Since we are short handed at Chrysler these days, I'm at the beginning of a very busy travel schedule. I'll be online, but with long work days, trip planning, and being away from some of my pictures, I can't predict my frequency of posting over the next few months.

Here is hoping that all this hard work results in more jobs and security for everyone.