Ask S&V

Mark Warner

The LP130 is not a home-theater projector—it's a business-presentation projector with a native aspect ratio of 4:3 and a resolution of 1024x768. According to the specs, the projector's only input is M1-DA, which is an InFocus version of DVI designed for computers; it has no component or any other type of input. You could try a component-to-HDMI converter, but I've never used one, so I have no idea how well these devices work. Also, according to some reports, you'll need a special M1-DA cable available from InFocus.

All in all, this is a highly compromised situation for a home theater. I strongly recommend getting a real home-theater projector.

When is 1:1 Not 1:1?
I just listened to your hardcore-calibration podcast with Joel Silver—great discussion, very informative. It got me thinking about the whole 1:1 pixel-mapping thing, and I want to make sure my TV is set correctly. My main content source is a Windows home-theater PC connected via HDMI to a latest-generation Samsung DLP RPTV. It has Picture Mode settings of Just Scan and 16x9.

When it is set to 16x9, the picture is overscanned, and when it is set to Just Scan, it is less overscanned, but the image still extends beyond the edges of the screen somewhat. I can use a software setting to squish the desktop view down to fit, but I assume this is less than ideal. The display resolution on the PC is set to 1920x1080/60Hz, and the info screen on the TV says 1080p.

Am I getting true 1:1 pixel mapping even though the desktop is off the screen a bit and seems to be overscanned?

Rodney Shetler

The Just Scan setting does result in 1:1 pixel mapping as far as the DLP imaging chip is concerned. However, rear-projection TVs rarely display all the available pixels, even if they are set to their 1:1 mode, because it's very difficult to align the optical engine perfectly with the screen. So most RPTVs do a bit of "optical overscanning"—the projected image is slightly enlarged beyond the edges of the screen to hide any misalignment. I would still use the Just Scan setting to minimize this effect and avoid scaling artifacts in the visible image. And you are correct that scaling in the computer will degrade the image quality, so I would avoid that.

Power to the Equipment!
I bought an Onkyo TX-SR608 receiver, and I would like to protect it from power fluctuations. Should I buy a power conditioner or surge protector? What is the difference between them?

Toni Ricardo Eugenio dos Santos

Actually, there are more choices than the two you mention. A surge protector is designed to prevent power spikes due to things like lightning strikes from reaching the equipment. A power conditioner cleans up the AC waveform, removing noise that many believe degrades the sound of audio electronics and the image produced by video gear. Many power conditioners also include a surge protector.

Stabilizing power fluctuations requires a voltage regulator, which keeps the voltage fed to the equipment at a constant level despite fluctuations in the voltage from the wall. However, they work only when the wall voltage remains within a certain range. Many voltage regulators also include power conditioning and surge protection.

At the top of the heap is the uninterruptible power supply (UPS), which includes a battery to power the connected equipment for a short time if the AC power drops below a certain value or fails completely. A UPS can also include power conditioning, voltage regulation, and surge protection.

Which should you get? That depends in part on where you live. Is lightning a common occurrence? If so, a good surge protector is a must. Don't rely on a drug-store cheapie; get one with a clamping voltage of less than 400V, an energy-dissipation rating of 400 to 600 joules or more, a response time of less than one nanosecond, and an equipment-protection guarantee.

Do you sometimes experience brownouts or blackouts? If brownouts don't dip below 90V or so in the US and don't last for long periods of time, a good voltage regulator will probably do the job, but if long-lasting brownouts or full-blown blackouts are common, you need a UPS.

Most audiophiles insist that power conditioners improve a system's audio performance, but I haven't performed my own tests to determine this for myself. Well-respected power-protection companies include APC, Furman, Panamax, and Monster.

If you have a home-theater question, please send it to scott.wilkinson@sorc.com.