Posted Fri Oct 15, 2010 at 11:00 AM PDT by Joshua Zyber
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 [email protected].
Answers by Joshua Zyber
Home Theater Connection Basics
Q: I have an LCD TV (LG 32" LH70YR) and home-theater-in-a-box (LG HT353SD). For the time being, this is the only set up I can afford. I'm 15 years old, and I don't have the money yet to buy a real home theatre. What is the best (connection) for all this gears I have: cables, wires, or converters, etc. I really need your help.
A: From what I've discovered through online searches, I'm going to assume that you live in the UK, because both of these products are UK models. I see that your HTiB has a DVD player built in. You haven't mentioned what or how many other video sources you will be connecting: Blu-ray, cable/satellite TV, video game consoles, etc. Without that, I can only make some general suggestions.
Your TV appears to have both HDMI and Component Video inputs. HDMI is its best connection type for video, but Component Video (the set of red/green/blue RCA cables) is a close second. You will want to connect any video source to the TV by one of these. The DVD player in your HTiB doesn't have an HDMI output, but does have Component. So you should use that.
If your HTiB didn't already come with any, you will need speaker wire to connect the main processor component to the speakers. Speaker wire is rated by gauge, which is a measure of its thickness. The lower the number, the thicker (and better) the wire. I would recommend at least 14 gauge wire for all speakers. If you had higher grade equipment, you might want to use 12 gauge wire for the front three speakers, where the most critical portions of the soundtrack are directed. However, with your particular system, I don't think this is necessary unless you have very long distances between the processor and the speakers.
Unfortunately, your HTiB is a fully self-contained unit. It doesn't seem to have either any video inputs or audio inputs, just outputs. That means that you won't be able to connect any other video sources (like cable/satellite TV or game consoles) to it to benefit from surround sound. You will have to connect those directly to the TV – ideally by HDMI – and use the TV's own built-in speakers. HDMI will carry both video and audio together in one cable, so you won't need separate audio connections.
You should note that Component Video cables are not necessarily the same as the yellow/red/white "A/V" packages of three RCA cables. Although those will work in a pinch, they may slightly compromise picture quality. Each of the cables in a Component Video connection should be rated for 75 ohm impedance. In the "A/V" sets, usually only the yellow "Video" cable meets that standard (if even). The red and white cables are typically only rated for 50 ohm. If it's more cost effective, you can substitute three of the yellow Video cables for one set of red/green/blue Component cables. However, I wouldn't recommend any cheap thin cables that may have come packaged in the box with some of your equipment. Component Video is an analog signal, and is more sensitive to interference or signal loss than digital transmission. Quality cables are more critical for this application.
Home theater cables (especially HDMI) and speaker wire tend to be very overpriced at retail. You don't really need to spend a lot of money to get decent HDMI or Component cables. If you lived in the U.S., I would recommend buying from Monoprice.com. Perhaps some of our other readers can recommend similar value retailers in the UK?
PS3 "Bitstream Direct" vs. "Bitstream Mix"
Q: On my Playstation 3, I have the option of choosing "Bitstream Direct" or "Bitstream Mix" after a firmware update. I use an optical cable to get 5.1 surround sound. When I choose Mix, the audio sounds fuller and more clear. When I check the settings while the movie is playing, it displays DTS-HD MA or Dolby TrueHD, with a variable bit rate of 2.0 mbps and above, instead of DTS 1.5 mbps or Dolby Digital 640 kbps, like it did before. I was under the impression that you could not get lossless sound via optical, but it sure seems like I am when I choose Bitstream Mix. The official Sony page detailing the update only describes it as adding "sounds of button presses on the BD." So, am I actually getting lossless sound or is this a high bit rate lossy signal?
A: Unfortunately, you were right the first time. It is not possible to transmit the Dolby TrueHD or DTS-HD Master Audio formats in full lossless quality over an S/PDIF cable (either Toslink optical or digital coaxial). This type of connection is limited to standard Dolby Digital 5.1, standard DTS (up to 6.1), or two channels of PCM.
The difference between "Bitstream Direct" and "Bitstream Mix" determines whether the PS3 performs any internal audio decoding. The "Direct" setting will extract the data from the disc and send it to the A/V receiver without any audio processing. If you're using an optical cable, the console will only extract the DTS "core" (not the DTS lossless extension) or the backup Dolby Digital track embedded along with a TrueHD track (not the TrueHD signal itself). Because the console isn't doing any processing, it cannot perform live-mixing of any supplemental audio such as menu button noises or the audio content for Bonus View picture-in-picture features. You will only get the movie soundtrack itself.
For the "Bitstream Mix" setting, the console will first decode the original Dolby or DTS soundtrack internally, live-mix in any of that supplemental audio, and then re-encode the results back to a Dolby or DTS form. Your A/V receiver will report receiving a Dolby or DTS bitstream signal, which it then has to decode again. But that bitstream is comprised of both the original soundtrack and new audio content mixed with it.
As to why you seem to hear a difference in audio quality between these two settings, there are two possibilities. Allowing the PS3 to decode internally and then re-encode into Dolby or DTS may result in a volume difference if the PS3 were to strip away certain metadata such as Dialogue Normalization values. A difference in volume is not truly a difference in quality. A louder soundtrack is not actually better; it's just louder. If you make the effort to volume-match the soundtrack both ways with a sound level meter, the audible results should equalize.
Perhaps even more likely is that this is simply placebo effect. Your brain expects to hear a difference between the two settings, and allows itself to be influenced by that expectation. Placebo effect is a very real and very powerful force in human perception. The best way to eliminate this factor is to perform a double-blind listening test where you must evaluate the options without knowing which is which.
Once again, I'm going to forego a Homework assignment this week in order to highlight this piece of Reader Feedback on an important issue.
Misleading "HD" Advertising
Q: This has more to do with the business side of HD than the hardware side. I just received a booklet letting me know about some "new" DirecTV features (I'd already been aware of them for a while). In a section bragging about the HD movie selection, it says that movies can be delivered in 1080p, "the same stunning quality as Blu-ray". Now I know this isn't true and that DirecTV doesn't approach Blu-ray's quality. 1080p is only the resolution and just one of many factors (like bit rate) that make up quality. I'm just wondering how they can even claim this. I had heard that Dish Network was made to pull ads claiming "same quality as Blu-ray" some time ago. I started to notice them saying "same resolution" instead, which is at least accurate. I work in the electronics section of a retail store and this is the type of thing that confuses people and makes them afraid of HD. I try to clarify because it all starts to sound too complex when you have to explain WHY Blu-ray is actually better. While I would love a world where everyone is simply well educated on the expensive things they buy, we depend on all types getting into Blu-ray to keep the movies coming.
JZ: I fully agree that these sort of claims are misleading at best and borderline fraudulent. If our readers have seen similar advertisements for other sources that claim to be Blu-ray quality but clearly aren't, please discuss in the forum thread linked at the end of this article.
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.
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