Common Confusion in Home Theater: Part 5

3d1This post is part of my series of blog posts and slideshows regarding topics of common confusion in home theater. In this post, I cover HDMI, including the issue of cable length and the controversial value of expensive cables.

  • Part 1: Volume and zero dB, updating firmware, Blu-ray disadvantage
  • Part 2: Speaker resistance, analog vs. digital amps in AV receivers
  • Part 3: PCM vs. bitstream, Blu-ray player upscaling/upconversion
  • Part 4: THX certification, DLNA network access, and distortion and THD
  • Part 6: Closed-back vs. open-back around-ear headphones
  • Part 7: Understanding your room and room dynamics
  • Part 8: Room correction, speaker position, and more room dynamics
  • Part 9: Ethernet, component separates, and broadband internet routers

Thanks for reading. Don’t forget to leave a comment if you have questions or feedback.

curtsig2 - trans
Curt Robbins


HDMI

HDMI, the acronym for High Definition Multimedia Interface, has finally replaced a variety of older connection standards in home theater (and computers). Even the most barebones entry-level TVs and receivers feature at least a couple of HDMI ports. It’s now a fully ubiquitous standard that’s going to be around for a long time. The greatest attributes of HDMI are that it is fully digital, carries both high-resolution audio and high-definition video on a single cable, and allows you to connect mobile devices like camcorders and smartphones to your home theater.

There are two types of HDMI cables: Standard and high-speed. Standard is capable of lower-quality (interlaced) 1080 video, while high-speed varieties provide you with the full quality of which Blu-ray discs are capable. Always purchase a high speed type, preferably one that supports 3D and something called Audio Return Channel.

Covers All Components

Old school analog connection standards, such as S-Video, composite audio/video, and component video are now dinosaurs, their bones scattered across the same wasteland as TV-top rabbit ear antennas and cassette tape decks. The fact that nearly all home theater components can be connected via HDMI makes things much easier. HDMI makes things so simple, in fact, that your biggest challenge becomes ensuring that you have cables of the proper length (so you don’t, for example, come up two feet short of what’s necessary to connect your receiver to your TV). Home theater is a lot nicer when the length of your cables, and not their type and expense, is your biggest concern.

Cable Length Limits

HDMI cables were originally developed to not exceed roughly 16 feet in length. The three foot (one meter) interconnects used to input Blu-ray players and set-top boxes to receivers aren’t a concern here. However, it’s not uncommon for a display panel TV to be on the other side of the room from the AV receiver feeding it. This is certainly an option that should be available to you when you’re planning or upgrading your home theater. However, this type of arrangement requires a long HDMI cable to be run through the walls or floor.

Lengths greater than 20 or 30 feet can, under the right conditions, produce undesirable results, such as no picture or an image that suddenly disappears. This is determined largely by the quality of the equipment connected to the HDMI cable, namely the receiver and display panel. Properly implemented HDMI ports that support the latest HDMI standard (obviously possible only on newer equipment) are more capable than those found on lower quality, older equipment.

There are two solutions for long HDMI cable lengths. First, you can purchase a hardware device that acts as an HDMI signal booster. An example is the Spectrum Electronics DSR-701 Digital Signal Restorer. This $280 device is well-reviewed and said to do an excellent job with cable lengths up to 100 feet. Second, you can convert HDMI cable to CAT6 cable using a special converter box or adapter, with the majority of your cable run in the form of CAT6. When the cable reaches your TV, it must be converted back to HDMI using a similar sister device. This allows lengths of up to 100 feet to be achieved with no video performance degradation. One reputable converter box set is the $140 Ethereal Home Theater CS-HDC5EXTD, which supports up to 90 foot (30 meter) cable runs.

If you’ve already installed a long HDMI cable in your floor, walls, or ceiling, you probably don’t want to endure the expense and hassle of installing an additional CAT6 cable. Thus, for many consumers with existing HDMI cable runs, something like the Spectrum Electronics Digital Signal Restorer will be the most straightforward solution—and possibly the least expensive when professional cable installation costs are taken into account. For new installations, I’d recommend running both high-speed HDMI and CAT6 cable, giving yourself the option of whichever solution most appeals to you (and further future-proofing your home theater). When possible and practical, a set of $60 to $150 HDMI-to-CAT6 and CAT6-to-HDMI conversion adapters is certainly more cost effective than a roughly $300 HDMI signal booster (saving you money for your speaker budget).

Are Expensive HDMI Cables Worth It?

All high-speed HDMI cables are the same. Let me say it again: All high-speed HDMI cables are the same! For the most part (at distances under 20 feet or so), an $8 cable performs just like a $200 cable. I know, it sounds like a conspiracy. But the fact remains that an expensive cable offers almost zero improvement over a cheap model (as long as it’s a high-speed type). You simply want to avoid crappy cables featuring poor build quality and little insulation (such as the two-for-$5 specials at your local discount store).

Don’t let a big box electronics store convince you that an expensive gold-plated HDMI cable is necessary for a quality home theater experience. Profit margins are highest on accessories like cables, cases, cleaning accessories, and spare batteries. Ironically, big box electronics retailers make the least profit on big ticket items like speakers, receivers, and Blu-ray players, so they try to make it up with accessories like cables. Salespeople argue, “If you spent all this money on your equipment, why shortchange your investment with cheap cables?” While this is great logic, and an argument frequently employed, it’s simply false in the case of HDMI.

In fact, the very nature of HDMI, which is a fully digital signal, means that it’s either nearly perfect or there’s no picture whatsoever. Unlike the old over-the-air analog broadcasts of the past, there’s no in-between where a fully digital video signal can degrade with snow or static, but still be viewable. Video and audio carried via HDMI is either there or it isn’t.

When I last upgraded my home theater, Best Buy tried to convince me to purchase several short HDMI interconnect cables costing about $85 each. An $8 cable from Amazon provided me with the same quality. Still not convinced? Check out the blog article Why All HDMI Cables Are The Same by Geoffrey Morrison of CNET.


Curt Robbins is author of the following books from Amazon Kindle:

You can follow him on Twitter at @CurtARobbins, read his AV-related blog posts at rAVe Publications, and view his photos on Flickr.

Common Confusion in Home Theater: Part 3

3d1As part of my mini-series of blog posts and Slideshare slideshows regarding topics of common confusion in home theater, below I cover PCM vs. bitstream and Blu-ray player upscaling/upconversion.

This series features excerpts from my new Kindle book Home Theater for the Internet Age.

  • Part 1: Volume in a zero dB world, updating firmware, and the disadvantages of Blu-ray
  • Part 2: Speaker resistance and analog vs. digital amps in AV receivers
  • Part 4: THX certification, DLNA network access, and distortion and THD
  • Part 5: HDMI (including cable length and controversial expensive cables)
  • Part 6: Closed-back vs. open-back around-ear headphones
  • Part 7: Understanding your room and room dynamics
  • Part 8: Room correction, speaker position, and more room dynamics
  • Part 9: Ethernet, component separates, and broadband internet routers

curtsig2 - trans
Curt Robbins


Upscaling / Upconversion

As you’ve already learned, DVDs feature a video resolution of 480 horizontal lines. When compared to Blu-ray’s 1080 lines, DVDs seem pretty wimpy. But if you have a large (and expensive) DVD collection, you probably don’t want to simply trash or sell them. Re-purchasing your collection is frustrating and expensive. Damn you, double-edged pace of technology!

Most Blu-ray players (and many AV receivers) automatically apply something called upscaling, or upconversion (both terms are used interchangeably) to DVDs in an effort to make them 1) fit on a 1080 TV, so they’re not displayed as a little box in the center of the display panel, and 2) appear to be higher resolution than they actually are (by simulating 1080).

In a nutshell, this means the Blu-ray player analyzes the video content of a DVD and adds more lines, creating a pseudo-1080 image. While upconverted 480 video doesn’t look as good as the native 1080 display of Blu-ray content (with 1080 unique lines, featuring none of the pixel redundancy that comes with upscaling), it does look better than standard 480. In terms of the end result, upconversion for video is akin to matrixed surround sound for audio: It’s all about optimizing legacy media formats on modern-generation equipment. (To learn more about matrixed and discrete surround sound formats, see the Surround Sound chapter.)

The quality of upconversion is determined entirely by your equipment (the hardware and software running within it; see the Video Processing section below for more info). Better Blu-ray players do a superior job of upscaling than their less-expensive siblings. The $300-$600 players offered by companies like Denon, OPPO, Onkyo, Pioneer Elite, and Marantz will do a considerably nicer job of upconversion than an entry-level $80 Sony or Samsung unit (which aren’t the best suited for home theater environments).

A standard definition DVD will never look better than when upconverted on a home theater with a decent Blu-ray player. So what’s your takeaway? Don’t sell those old DVDs on Craigslist or relegate them to a dusty box in a closet! If you’re willing to tolerate the slight decrease in quality between upscaled DVDs and native Blu-ray content (which many people don’t even perceive), upconversion can help you avoid rebuying your DVD movie collection. Also consider that the majority of discs available from your local video rental store or library—even in 2014—are DVDs, not Blu-rays.

Real-World Upscaling

One study claims that 39% of viewers can’t tell the difference between standard-definition video (480 lines of resolution, as featured on DVDs and old camcorders) and high-definition content (1080 on Blu-ray discs or streamed via a service like Netflix). If this is even marginally true, an even greater percentage of consumers will be oblivious to the difference between an upscaled DVD featuring “fake” 1080 resolution and a Blu-ray disc producing the real thing. If you’re one of them, keep your eyes peeled for those grocery store bargain bins full of clearance DVDs. (Your local brick-and-mortar video store—if your community still has one—is another great source of discounted new and used DVDs.)

Video Processing

Your Blu-ray player’s video processing is handled by a dedicated computer chip (or set of chips) and special software stored on it. Many manufacturers utilize fairly generic, average processing chips—which don’t always produce the best results, especially when upscaling DVDs to 1080 resolution. More potent models feature special leading edge video processing technologies licensed from third-party companies, such as Marvell’s Qdeo and Silicon Image’s VRS ClearView.

Many popular Blu-ray models, including those from Cambridge Audio, OPPO, Onkyo, and Pioneer Elite, feature Qdeo processing. Note that there are several generations of Qdeo, so one from three years ago won’t be as good as what’s shipping on current models. OPPO’s top Darbee models feature VRS ClearView video processing and upscaling.

PCM vs. Bitstream

If you’re connecting your Blu-ray player to your receiver via HDMI, there are two options for how data is sent from the player to the receiver. The first, PCM (Pulse-code Modulation,  sometimes called LPCM), is when your Blu-ray player performs all decoding of the compressed audio on the disc (a variant of either Dolby or DTS). In this scheme, the fully decoded audio is sent to your receiver, then passed along to your speakers. Many receivers allow you to select PCM output from the same menu from which you choose DLP sound fields (and will indicate the mode by displaying “PCM” on the front panel).

Bitstream, on the other hand, means your Blu-ray player does the opposite, performing no decoding of the compressed audio of the disc, instead sending along the raw, encoded bitstream to your receiver, where the decoding takes place. In this case, the receiver will display the exact encoding method employed by the disc (Dolby TrueHD or DTS-HD Master Audio, for example). The only disadvantage of bitstream is that any “secondary audio,” such as commentaries and other supplemental features of Blu-ray, will be lost. If you ever use these features, you obviously should lean on PCM.

Typically, both methods work equally well and, in practical applications, it doesn’t really matter which you employ. However, if you had a much nicer (and newer) Blu-ray player than receiver, you might choose to have it do the heavy lifting to improve the quality of the audio pumped into your speakers. If both your Blu-ray player and receiver are of relatively equal capability and age, the difference between these two schemes will almost certainly be negligible.


Curt Robbins is author of the following books from Amazon Kindle:

You can follow him on Twitter at @CurtRobbins, read his AV-related blog posts at rAVe Publications, and view his photos on Flickr.