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Saturday, July 20, 2002

Run Silent, Go Feep -- Adventures in Quieting A Computer:

Warning: The following blog entry provides way more than the recommended daily allowance of geeking. If you don't have a serious propeller-head streak, surf outta here now before it's too late.

I'm mainly a software guy, but occasionally I build PCs for fun. Design them, rather; the further away I stay from actual hardware the happier it usually is for everybody. Last year, I designed an Ultimate Linux Box; the good folks at Los Alamos Computers built it and will cheerfully sell you one. It was a successful design in most respects, but unpleasantly noisy. This year, as we do the 2002 refresh, I'm going to be working hard at getting the most noise reduction I can without sacrificing performance. I'm experimenting now with ways and means.

So I spent a couple of hours today disassembling the case of my wife Cathy's machine ( and lining three sides of it with Dynamat, a kind of stick-on rubber acoustic insulation often used in car-stereo installations. The malevolent god that normally attends me when I futz with hardware must have been off tormenting some other hapless ex-mathematician; no hardware was destroyed, no blood was shed, and I'm typing this on the selfsame reassembled machine.

Minx is a pretty generic mid-tower system made with cheap Taiwanese parts in mid-2002 by my local hole-in-the-wall computer shop: I spent only $150 to have it built, recycling a few parts from an only slightly older machine. It has a 300W power supply, Athlon 950 mobo with stock CPU cooler fan, one 80mm case fan, 7200RPM ATA drive. I succeeded in lining both 14"-square side panels and the case top; this used up the 4'sq piece I bought so efficiently that there was only about 10"sq in two small piece left over. I used those to cover the only exposed solid section of the back panel.

If you want try this yourself, the tools I found useful were a utility knife and a metal footrule, the latter useful both for measuring to fit and as a cutting guide.

I took before and after measurements with the db meter. dbA scale, measurements made with the probe one inch above the center-rear edge of the case.

Machine off:44dbA
Machine on, before:63dbA
Machine on, after:61dbA

In other words, only a 2dbA drop -- marginal when you consider that the meter is only rated 1.5dB accurate! but it's worth bearing in mind that the scale is logarithmic; 2dbA is more than it looks like.

I have studio-engineer ears and sensitive musician fingers. I took before-and-after measurements with those, too, listening to the sound tambre and feeling for case resonance.

My ears tell me that the box is only slightly quieter, but the noise spectrum has changed. The proportion of high-frequency noise has dropped; more of what I'm hearing is white noise due to turbulant airflow, less is bearing noise. This is a good change even if total emission hasn't dropped much.

My fingers tell me that the amount of case resonance has dropped quite dramatically, especially on the side panels.

Was it worth doing? I am not sure. There would probably be more benefit on a system emitting more bearing noise from 10K or 15Krpm drives. On this one, I think the power supply is emitting most of the noise, and acoustic lining can't do much against that.

In fact, my clearest take-away from this is that the big gains in noise reduction on conventional PCs are likely to come from obsessing about power-supply engineering -- including details like whether the fan blows through a slotted grille or a cutout with a wire-basket finger guard (the latter will generate less turbulence noise).

I'd like to retrofit minx with a Papst 12dbA muffin fan and see if that makes a measurable difference. But the best change would probably be one of the Enhance 300W PSUs that are supposed to only emit 26dbA. I'll bet that would win big.

posted by Eric at 4:18 PM          

Wednesday, July 17, 2002

Traveling in Texas:

I was on the road in Texas last week, addressing Linux user groups in Dallas and Austin. I always enjoy visiting Texas. It's a big, wide-open place full of generous people who cultivate a proper appreciation of some of my favorite things in life -- firearms, blues guitar, and pepper sauces.

And, of course, one of the biggest things Texas has going for it is barbecue. And not the pallid imitation served up by us pasty-faced Yankees here where I live (near Philadelphia, PA) but the real thing. Barbecue, dammit. Red meat with enough fat on it to panic a health-foodist right out of his pantywaist, slow-cooked in a marinade sweeter than a mother's kiss and eaten with sauces hot enough to peel paint. Garnish with a few extra jalapenos and coleslaw and wash it down with cheap soda, lemonade, or beer. Food of the gods.

I swear your testosterone level goes up just smelling this stuff. After a few mouthfuls of Rudy's carnivoral bliss you'll be hankerin' to cultivate a drawl, wear a Stetson and drive a pickup truck with a gun rack. (I draw the line at country music, though. A man's got to have some standards.)

At a real barbecue joint like Rudy's ("Worst barbecue in Texas!") they serve you piles of beef, pork and chicken wrapped in butcher paper in a plastic basket. No plates, just more butcher paper and bread. And, unfortunately, the bread is where this gustatory Nirvana nearly crashes back to earth. Because the bread at real barbecue places is invariably utter crap -- spongy sliced white with all the taste of building insulation.

Here in Philadelphia we can't make barbecue worth a damn, but we know better than to put a hot sandwich on American bread. One of our regional-food glories is the Philly steak sandwich, fried beef and onions and mushrooms (and usually cheese, but I don't eat cheese) nestled in a foot-long Italian roll. The bread is important. It's tasty, it's chewy, it's got a crust on it. It's worthy of respect.

One of the reasons you can't get a decent steak sandwich more than fifty miles from Billy Penn's hat is that bread. It depends on an Italian baking tradition that just doesn't exist outside the mid-Atlantic metroplex, and is found in its highest form only in Philly and South Jersey. Philadelphians laugh at the pathetic imitations of "Philly steaks" offered elsewhere for the same reason Texans laugh at barbecue made north of the Mason-Dixon line. And both groups are right to laugh. It just ain't the same.

Every time I order up a mess of barbecue at a place like Rudy's or County Line or Dick's Last Resort I think to myself "Someday, one of these barbecue outfits has got to start offering decent bread. Their sales would go through the roof." I've been waiting for the market to correct this problem for more than twenty years now -- and it hasn't happened. And thereby hangs a mystery.

The mystery is the curious persistence of regional food differences in a country with cheap transport and the best communications network in the world. There are places in the U.S. where you can reliably get really good bread -- mostly the coastal metroplexes. There are places you can get real barbecue, in the heartland South and Southwest. And these zones just don't overlap. (Yes, they have a gourmet-bread bakery in Austin. I suspect, if I went there, I'd find it a lot like the Chinese food in Ann Arbor -- impressive to the locals, maybe, but only because their standards are so low.)

I could multiply examples. Sourdough bread -- I've had it everywhere you can get it and it just doesn't taste right outside of San Francisco. The East Coast versions are competent, but lack some subtle tang. Yeast strain? Something in the water? Who knows?

Cheesecake. There's a good one. Anybody who has lived in New York won't touch most cheesecake made elsewhere at gunpoint, and with good reason. Next to a traditional New-York-style baked cheesecake (the kind you can stand a fork in because it has the approximate density of neutronium) all others are a sort of pathetic, tasteless cheese gelatin. In this case the recipe is clearly what matters.

Or deep-dish pizza. Try to get that done right anywhere but Chicago. Good luck. Actually, the Philly/South Jersey area may be the only other part of the U.S.that can almost make this nut, and our thin-crust pizza is better. But why? Why don't the good techniques go national and drive out the weaker competition?

The obvious answer would be that nationwide, tastes differ too much for one regional variant to dominate. But many cases there isn't even any dispute about where the best variant comes from; the superiority of "New York style" cheesecake. for example, is so universally understood that restaurants elsewhere often bill their cheesecake that way even when it's actually half-composed of "lite" garbage like ricotta or cottage cheese. Nobody who has ever tasted one doubts that Philly steaks are the acme of the art. And nobody -- but nobody -- who can get both passes up Texas barbecue for what they make in New Haven or Walla Walla.

So you'd think that the market would have propagated Texas slow-cooking, San Francisco yeast starters and the Philly steak roll all over the country by now. But some food technologies travel better than others, and some seem curiously unable to thrive outside their native climes. Cheesecake recipes may survive transmission relatively well, but the mysteries of good barbecue are subtle and deep. Pizzas rely on elaborate oven and dough-mix technology that probably tends to conserve regional variations simply because it's too capital-intensive to mess with casually.

I've meditated on the matter and still can't decide whether I think that's a good thing or not. The approved thing for travel writers to do is wax lyrical about the wonderfulness of regional variety, as if it would somehow fail to be an improvement in the world if I could get decent bread with my barbecue. The hell with that kind of sentimentality; I'd rather have a better meal.

But there's a point buried there somewhere -- something that isn't about the bread or the barbecue, but about what it feels like to sit in a dusty roadside joint like Rudy's,surrounded by cases of Red Pop and overweight rednecks in tractor caps and checked shirts, with the food of the gods melting in your mouth, and thinking "Damn, this place is tacky, but I hope it lives forever."

And you know what? I suspect that kind of barbecue joint will live forever, or as close to forever as humans manage, anyway. They've probably existed since the first proto-hominids roasted mammoth haunch over a slow fire, washing it down with some badly-made tuber-beer equivalent of Red Pop. And their equivalents will probably persist in the zero-gee arcologies and Dyson spheres of the year 3000. Even if they get hip about the good bread, somewhere in the universe there will always be a Texas. And that's a good thing.

UPDATE: Some respondents have reminded me of the Piedmont (and specially North Carolina) tradition of pulled-pork barbecue. Let me state for the record that I find it equally delicious. Both the Texas and Piedmont versions are so damn good that there is no call for petty disputation about which is superior. But for those of you who know what I am talking about, I am quite partial to burnt ends.

UPDATE: Jane Galt has commented in her usual witty and illuminating fashion.

UPDATE: The mystery of San Francisco sourdough, was, as it turns out, solved in 1970. You can buy a starter with the proper symbiosis of bacteria and yeast -- and, contray to myth, local bacteria won't overwhelm it. Of course this makes it harder to understand why the stuff isn't everywhere...

posted by Eric at 7:10 AM