Ask S&V

Greg Tuer

You bring up an excellent point! Different media sources generally do require different calibration settings to look their best. And different TV channels often need different settings, which is doubly frustrating.

Unfortunately, there's no way to display calibration test patterns from source devices other than disc players—for example, cable and satellite receivers and many game consoles—so calibrating the display for them is nearly impossible. HDNet broadcasts a few test patterns every couple of weeks for about 15 minutes in the middle of the night, and they're marginally sufficient for setting the basic picture controls, but not for a full calibration. And even if you set the basic controls with these patterns, other channels will probably need different settings anyway.

The best solution is to do a full grayscale calibration on the disc-player input and use the same settings on the other inputs (unless the grayscale can only be calibrated globally, in which case that's all you can do). Then, tweak the basic picture controls for the broadcast-receiver and game-console inputs by eye, using skin tones as a reference for the color and tint controls.

If you're using an A/V receiver or preamp/processor as a switcher with one cable going to the TV, and the TV provides full access to all controls in each picture mode, mentally assign a different picture mode to each source device and tweak it as best you can for that device, then select that mode when viewing that device.

Crossover Conundrum
I have a question concerning my home-theater setup. The frequency response of my front L/R speakers is 43Hz-20kHz, center is 38Hz-20kHz, surrounds are 80Hz-20kHz, and the sub is 23-180Hz with a variable crossover frequency (40-180Hz). My A/V receiver has bass management with a fixed crossover for the sub at 100Hz. What would be the optimal settings for my setup?

Vader373

It's interesting that the center speaker goes lower than the front left and right—normally, it's the other way around. I would use the bass management in the AVR, even though its crossover frequency is a bit higher than the THX recommendation of 80Hz. In the AVR's menu, set all main speakers to "small" and specify that the system includes a subwoofer.

If the sub provides an input that bypasses its internal crossover, connect it to the LFE output from the AVR. If there is no such input but the sub provides a crossover-bypass switch, engage it. If there is no such switch, set the crossover frequency as high as possible, which effectively takes it out of the signal path when the only frequencies reaching the sub are 100Hz and below.

Amp vs. Amp
Over the last 20 years, I have used two A/V receivers with external amplifiers because I believe that amps with separate power supplies sound cleaner and more dynamic. Would you say that this is still the case with receivers manufactured in 2010 by any of the major brands? In other words, do external amps still sound better than those built into receivers, or has receiver technology caught up?

Ted Walters

My first thought is, why not use a preamp/processor if you know you're not going to use the amps in the AVR?

I think separate power amps will always perform better than the amps in AVRs for just the reason you state, but that gap gets smaller with each passing generation of electronics. Modern AVRs sound excellent, but if you want that extra bit of performance, separates can give it to you.

Home Theater's audio technical editor, Mark Peterson, had this to say about your question: "I generally agree with the reader. On a system in my house, I use external amplifiers for the front left and right and let the AVR handle the other channels. Once the left, right, and sub have been offloaded to external amps, there is usually plenty of amplifier/power supply capacity available in the AVR for the center and surrounds. Also, if all main channels are operating above 80Hz or so, and the speakers aren't especially demanding loads, then it's less of an issue than it might be otherwise."

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