Editor's Note: Each Friday, High-Def Digest's own HD Advisor will answer a new round of questions from our readers. If you have home theater questions you need answered, send an email to HDanswers@gmail.com.
Answers by Joshua Zyber
Receiver vs. Separates
Q: Recently, I learned about the possibility of using a separate audio processor in a home theater system, rather than an audio/video receiver. I've even heard that this is much better. For people who are just movie watchers, not necessarily audiophiles, is it worth using a processor instead of a receiver? What consequences will this have, in terms of other equipment and cabling? Are the claims about the superiority of processors exaggerated?
A: Those readers who've followed this column for any length of time will probably recognize that I've never claimed to be an audiophile. In fact, I often approach many audiophile beliefs and practices with skepticism. I try to take a practical view of home theater matters. If the alleged superiority of one method of doing things can't be explained rationally or measured scientifically, I don't put much stock in it.
The audio data on a DVD or Blu-ray disc must go through three steps before you hear the movie's soundtrack through your speakers. First, the Dolby or DTS codec must be decoded to PCM format. Then that PCM must be converted to analog. Finally, the analog signal must be amplified out to the speakers. (Obviously, if a disc is authored with a PCM soundtrack, you will skip the first step.) An A/V receiver combines all three of these steps into one piece of equipment.
Many audiophile listeners prefer to separate these functions into dedicated processor and amplifier components. The processor will do the decoding and Digital-to-Analog conversion. The amplifier's name explains itself. The reasoning here is that dedicated, high-end components are more likely to do each individual job better than a combination unit.
There's actually merit in this line of thought. I won't argue against it. Any sort of all-in-one device will by nature introduce compromises somewhere along the way. However, I think that most home theater users, even most fussy listeners, will be perfectly well served by an A/V receiver. Separates are mainly for the die-hard audiophile crowd. I certainly won't begrudge anyone who goes this route, but I personally find that a receiver suits my needs just fine.
If you were to use separates, you'd of course need to connect the processor to the amplifier. Because the processor converts the audio signal to multi-channel analog format, you will have to connect the two devices by 5.1 (or 7.1) analog cabling. That means between 6 to 8 additional cables that you would otherwise avoid by using a combined A/V receiver. Should that in itself be a deal-breaker for an interested viewer? No, but it's something to take into consideration for those on the fence.
Dolby Digital on HD Broadcast
Q: I have always wondered how the quality of the Dolby Digital 5.1 audio on HDTV is when compared with the Dolby track on DVDs? Is the TV sound more or less compressed? Is there any hope we could have Dolby TrueHD or DTS-HD Master Audio on broadcast TV?
A: Most HD broadcast networks use Dolby Digital 5.1 audio at a bit rate of 384 kb/s. A few may go up to 448 kb/s, comparable to the version of Dolby Digital most studios use on DVD, but that's rare for television. The sound quality of broadcast programs may vary by network and show. (I think 'Glee' sounds pretty great on Fox, but was never much impressed with the audio for '24' on the same network.)
Some cable and satellite providers have discussed upgrading to the Dolby Digital Plus format, which still isn't lossless quality but does offer more transparency than standard Dolby Digital. However, there hasn't been much movement toward actually implementing that, at least not here in the United States. In France, the TNT HD platform broadcasts a few channels in Dolby Digital Plus.
Positive vs. Negative Volume Numbers
Q: I'd think this would be a no-brainer for the column. Who hasn't wondered why the number displayed on the receiver goes down when the volume goes up?
A: Actually, different receiver brands handle this differently. Some brands (such as Onkyo, I believe) consider "0" to be the very bottom of the volume range. In other words, muted. When you turn the volume up, the numbers go up. Although that would seem to make the most logical sense, this is a minority approach.
Most receivers consider 0 to be "reference level" volume. While this isn't necessarily the highest volume the receiver can achieve, it's most likely the loudest that you'd ever want to listen to anything. In fact, you probably rarely want to crank the volume that high in a home environment. Depending on the size of the listening space, typically somewhere between 10 to 20 dB below reference (numbers in the negative range) will be very audibly loud. This is assuming that you've calibrated your speaker levels at the receiver against reference level, of course. (Which is what any calibration disc will instruct you to do.)
The HD Advisor knows many things, but he doesn't know everything. Some questions are best answered with a consensus of opinions from our readers. If you can help to answer the following question, please post your response in our forum thread linked at the end of this article. Your advice and opinions matter too!
Entry-Level HD Audio Receivers
Q: I am looking for an entry-level HD Audio solution. My current receiver handles Dolby Digital and DTS via TosLink, but I'm possibly looking to upgrade. I'm hoping to keep the price tag under $500 (under $300 would be awesome). Basically, I am looking for something that will process HD audio from my PS3 and my HD DVD player. And I really want at least 800 watts. My current 800 watt system is comfortable with my volume near the max of the system. I am thinking that I might be able to go receiver only, and reuse my speakers from my Sony HTiB until I can get decent replacements. Also, one of the things I loved about my Sony was the mic, which would allow me to hold it at my listening position and it would set my speaker levels for me. Are these options even possible in my price range? Can I use my Sony speakers with another system? They are just regular speakers, right?
Check back soon for another round of answers. Keep those questions coming.
Joshua Zyber's opinions are his own and do not necessarily reflect those of this site, its owners or employees.