Dan's Data letters #108

Publication date: 8 June 2004.
Last modified 28-Apr-2012.

 

Output and input

Does using a higher refresh rate on my monitor, like 100Hz versus 80Hz, decrease the time required for it to get "burn-in"? I don't know if it is each refresh that contributes to burn-in or if it's just the amount of total time that the monitor is displaying something. I can't tell any difference between 80Hz and 100Hz, but the gamer in me sure likes the idea of 100Hz refresh. The monitor in question is a Cornerstone P1460 I've had for around five years.

Also, are there any Microsoft "Natural" style or ergonomic-in-any-way buckling spring keyboards in existence? I'd gladly pay a couple hundred bucks for a nicely built ergonomic keyboard.

Rob

Answer:
The refresh rate shouldn't make any difference to the aging of your monitor. Burn-in isn't a risk, anyway, unless you display the same thing for very extended periods; practically nobody manages to burn in a consumer monitor. If you're not running an old version of WinNT and leaving the log-in box up for weeks on end without blanking the screen, or running some point-of-sale sort of application with a static menu (perfect example: CRT-screened automatic teller machines), burn-in is not a risk.

Refresh rate also doesn't contribute to the general aging of a CRT screen, except in rare cases when it's higher than the screen is meant to handle - and modern monitors just go black when they're sent an out-of-range signal, so even that shouldn't cause a problem these days.

Regarding your keyboard question - I've looked into this issue from time to time, but I haven't actually so much as touched any of the 'boards I'm about to recommend. Specialist ergonomic keyboard companies tend to be unwilling to send out review product, probably because they've been burned over and over by newspaper journos who evaluate a keyboard that takes some getting used to for a whole ten minutes before they write their review.

Anyway, I think the keyboard that comes closest to what you want would be a Datadesk SmartBoard. They don't have the classic Alps-type clicky switches, but they're still clicky 'boards. Regrettably, a reader informs me that they're currently back-ordered, with no stock expected for the next couple of months.

The Northgate Omnikey Evolution might be even better, since it has Alps switches, but Northgate are defunct, so you'd have to hunt one up on eBay or something. A reader's pointed this dealer out to me now.

Both of the above 'boards are reviewed here.

The weirder Kinesis 'boards have mechanical keyswitches. I didn't know how clicky they were, though, and a couple of readers have now told me that the answer is "not very. Furthermore, only Kinesis' basic "Maxim" 'boards are in your price range. The Maxims have what's described as "quiet" keyswitches. So they can't be any good.

And then, there's Maltron. More expensive keyboards, with a very weird layout, but many people who suffer from RSI/CTS/whatever-it's-called-today rave about these 'boards. And nothing will make you feel more like a starship helmsman than this.

 

Coolest coolers?

I have just been wandering around Computex Taipei, and find that people are quoting thermal resistance figures much better that the best I have seen on your site.

I have seen figures quoted such as 0.25C/W, 0.33 - one company has an award from Intel for a 0.33C/W cooler - and a 0.27.

How are they getting much better figures than you? Are they fudging etc? Or these just a new crop of great coolers?

Stuart

Answer:
As I mention in my cooler comparison, results from my testing rig are only comparable with other results from my testing rig. Any CPU-simulating heater with a thermal probe embedded in it will give low thermal resistance results if the probe is relatively far away from the heater element, and high ones if the probe's close to the element, as it is in my heater. In neither case is there any direct connection to the performance the cooler will deliver on a real CPU; real CPUs aren't a constant heat source in the first place, and have thermal sensors in different places relative to their major hot spots (many older CPUs don't have internal thermal sensors at all). And internal probes can give different results on different motherboards; motherboard hardware monitoring calibration is usually pretty good, but can be seriously skewed in some cases.

But my test rig results should still tell you which coolers will work the best. They just won't tell you exactly how hot a given processor will be with a given cooler on it.

Cooler manufacturers get such low numbers because they generally quote the thermal resistance of their cooler alone, starting their measurements from the base of the heat sink, not from the thing that's heating it. This removes one thermal junction from the setup being tested. That's all very well, but it's misleading too; the quality of the thermal contact between CPU and heat sink is important to the total performance of the assembly.

There's no standard for computer heat-sink-fan (HSF) thermal resistance testing, so while results from one manufacturer may be comparable with each other, there's no reason to believe that one manufacturer's "0.2C/W" cooler is actually any better than another manufacturer's "0.3C/W" one.

That said, though, the new wave of fancy heat-piped big-fanned coolers genuinely are, often, very good performers indeed.

 

But I'm leaving the wife at home

I was wondering if you know whether or not airport X-ray machines cause damage to hard drives. I'm taking my HDs with me on vacation.

Martin

Answer:
There's no risk. Metal detectors shouldn't be a problem, either, because their magnetic field isn't nearly strong enough to affect hard disk platters. Metal detectors might, just possibly, be able to flip bits on floppy disks or corrupt analogue tapes, but even that isn't very likely, and X-ray machines are completely harmless to magnetic media. Note that they're not necessarily harmless to photographic film, though, especially high sensitivity "fast" film. That, you should keep off the X-ray conveyor belt.

 

The de-shine-ulator

Just a thought about the "shiny things" part of your photo tutorial. Buy a polarizing filter, problem solved - of course, unless you WANT it to reflect something.

Andrew

Answer:
A polariser certainly can reduce unwanted reflections, and it's often great if you're shooting through glass or water or something and don't want reflections from the surface to show up, but there are significant limitations.

One: Metal (including metallised coatings on plastic, in mirrors, and so on) doesn't polarise reflections at all. A polarising filter will do precisely nothing to a picture of anything shiny and metallic, unless the subject is illuminated with already-polarised light (like skylight without direct sunlight, for instance, or light from a hot light or flash that's itself equipped with a polarising filter).

Two: The amount by which a non-metallic shiny surface will polarise light bouncing off it is determined by the angle of the light and the refractive indices of the reflective surface, and of the other medium the light is passing through (usually air). For photographic purposes, the "Brewster's angle" of illumination at which the light has to strike the surface in order to be 100% polarised when it bounces off will be somewhere in the neighbourhood of 40 to 50 degrees.

So, when photographing a shiny object and using a polariser to reduce glare, you have to jockey your camera and/or subject around to try to get the reflection angle right. The further away from the Brewster's angle is the reflective bend in your line of sight to a source of glare, the closer to nothing your polariser will do, no matter how you align it (unless, again, you're using a polarised light source in the first place).

It is, of course, impossible to achieve something close to the Brewster's angle line of sight for the whole of many non-flat shiny objects, though that often doesn't matter much; the further away from the correct angle a part of the object is, the less likely it is to have glare on it from the light source, unless you're lighting it from multiple directions or with a very large single source.

 

Camera cable

Can you please tell me how or where to get ahold of the company that makes the Pen Cam Trio?

I have the Pen Cam camera but no USB cable, and I am having trouble finding one that small up here in Canada.

Eva

Answer:
The Pen Cam manufacturer is Aiptek (US site, Taiwan site), but they are not the people to go to for a new cable. What you want is a regular USB to mini-USB cable; I think the Aiptek cameras use a five pin mini-USB connector, but I wouldn't swear to it. You can tell by looking at the socket on the side of the camera. Find pictures of the five- and four-pin mini-USB connectors here.

Any decent computer store should be able to sell you a USB to mini-USB cable, provided you can tell them which kind you need.

UPDATE: Well, so much for that. Eva trundled around a few computer stores and found nothing that would fit. It would seem that the Pen Cam USB connector is not any kind of standard USB socket.

If Aiptek have used a completely non-standard connector, you're just not going to be able to fix the problem, unless you find out the pinout for the cable and get someone to make one up for you. The connector probably isn't actually an Aiptek invention, though - my next guess would be that it's a mini-FireWire plug, or something, that Aiptek have decided to use for USB for reasons known only to themselves. If that's the case, then anybody a bit handy with a soldering iron could take an appropriate FireWire cable and a USB cable and graft up a cable - but only if they knew which wire went to which pin, which is not easy to figure out without a crib sheet.

Since this little Aiptek is worth pretty much nothing these days, my revised recommendation is that you just buy another camera. It's not hard to find a camera like this, new, for $US20 or less; eBay's rotten with 'em.

 

PriceyCam

I was wondering if you could explain to me why buying a digital video camera from New York and shipping it to Australia then paying GST is still a ludicrous amount cheaper than trying to buy it anywhere in Australia?

Am I missing some not-well-known government charge that evens this out? Does Sony just like ripping Australians off? Will it actually work in Australia?

The camera is a Sony DCRTRV-950. At current exchange rates it should cost around $AU2800 to get it here, but the Australian Sony Web site claims its RRP is $AU4499 (street price $AU3600).

I'm thinking of getting it from here.

Paul

Answer:
One big reason for the price difference: The US version will be NTSC. The Australian version will be PAL. PAL devices are often a bit more expensive, because the PAL market is smaller. You probably don't want an NTSC video camera; lots of video gear sold in PAL countries these days understands both formats, but it's still a bit perverse to go with NTSC when you live in a PAL country.

This isn't as much of a problem for still photo gear, by the way; lots of digital still cameras have video output, but many of them are switchable between PAL and NTSC, and a lot of people don't care about this feature anyway. Video format is much more important for an actual video camera.

That said: Australian photo gear importers often charge large margins. I experienced this just the other day; I was toying with the idea of buying a new funky tripod head, and discovered that m'verygoodfriends at Dirt Cheap Cameras can't buy the thing significantly cheaper wholesale, locally, shipped by sea and not quite available yet, than I can get it myself by air from the USA - postage included, on my doorstep next week.

Some of this situation is justified, because the local distributors have to provide local warranty support, which can't help but cost them more than it would if they were in the USA or Japan, or possibly even Europe. Full-service dealer/importers who really take care of their customers can also be well worth some extra money.

Just as often, though, local distributors are basically just gouging. The tripod head pricing, for instance; there's no excuse for that. Tripod heads don't attract many warranty claims, and it's not a product that'll go stale on the shelf and be unsellable in a year.

If you don't mind going without a warranty (for practical intents and purposes), and can deal with the possible nightmare of the gadget turning up smashed (unlikely, but not impossible), then importing your own unit can be a very good idea, if there are no PAL/NTSC issues. AC adapters for fancy gadgets these days are almost always world-compatible, so that shouldn't be a problem.

When considering buying photo gear from overseas, though, beware of the really cheap dealers. B&H, the store you're considering, are fine; so are Adorama. Anybody who's a whole lot cheaper than them is probably a scam artist.

I note that Adorama stock both the NTSC and PAL versions of the camera, but they charge $US2049.95 for the PAL one (you have to use their cloak and dagger "send me a quote" thing to find this out), and won't sell either version online; you have to phone them.

There's not much reason to do this, of course; at $US2050 plus shipping plus GST, you probably wouldn't get much change from $AU3300, landed. For that small a saving, you might as well buy locally.

 

Sound switching

How can I have multiple PC's (in this case on one LAN) to play back audio on a single set of multimedia speakers?

The specific configuration I have is as follows:

Three PCs in close proximity to one another.

One of the PC's is equipped with a Hercules Game Theater feeding Monsoon MM-1000s. The other two have decent sound boards but no speakers.

All PCs share a common monitor, keyboard and mouse through a KVM, and I'd like to have them share the speakers as well.

I suppose I could daisy-chain the outputs of the other boxes into the Aux In on the Hercules GT but that doesn't seem like a very elegant solution, and would require manually changing the switches each time I change desired inputs.

Is there a hardware switching device that you know of, or a better solution that you have tried or heard of? Am I missing something obvious here?

John

Answer:
As some readers have pointed out to me, at least one KVM switch company now make KVMs that can switch audio along with Keyboard, Video and Mouse; see these Belkin models, for instance. One of those would solve your problem, provided you never wanted to not switch audio along with everything else. A reader's also pointed out to me that if you use WinXP's Remote Desktop, you can forward the remote PC's audio along with everything else; for some applications, Remote Desktop can save you from having to use a KVM at all.

If neither of these options appal, though, you can set up a manual switch quite easily and cheaply.

If you'll never want to listen to more than one of the computers at a time, then a simple input-selector switchbox will do. These things are made for people who need more inputs on their stereo, or whatever; they have one output (usually a pair of RCA sockets) and several inputs, and plain mechanical switching to select which input gets connected to the output. They're cheap; any decent electronics store should have a few. Using the switch every time you change computers will be a bit of a pain, but you don't have to do it every time, only when you need to hear sound from the machine you switched to.

If you want to be able to listen to two or more computers at a time - listen to all three at once and you won't need to switch anything, ever - then you'll need an active solution. Just Y-connecting together multiple leads will give you an impedance mismatch nightmare; what you need is a mixer.

Basic mixers with three sets of RCA inputs and, usually, a mic input or two as well, aren't terribly expensive. Here in Australia, you can get one for a hundred bucks from Jaycar. The sound quality of dirt cheap mixers is commonly quite horrendous, but the cheapest ones aren't that much more expensive than a passive switchbox. They're easy to find on eBay, too, along with cheap used mixers that probably sound considerably better.

 

If you sell it, they will come

You gotta see this one. A six foot power cable for $US492.

The parts that made me laugh are...

- "Incredibly fast and accurate transfer of power resulting in cooler and more efficient operation."

- "Patented technology allowing for unimpeded current flow."

Since when does it matter how "fast" the power gets to your equipment?

They also sell three foot RCA cables for $US440.

Bill

Answer:
And the RCA leads have a "finely cured wood housing for reduced outside interference". That electrical-interference-blocking wood of theirs (it must be the curing that does it...) could win them some prizes, even if the Nobel committee doesn't buy their room temperature superconductor claims for the power cord.

These cables are far from the most expensive ones out there, but it's disappointing to see Parts Express selling this kind of stuff; they're generally an excellent source of parts for the hobbyist speaker builder. Their own-brand "Dayton" drivers, in particular (as seen in this sub), are very good value for money.

If you want to ask me a question, feel free - but please read this and this first.

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