This 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.
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.
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).
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:
- Home Theater for the Internet Age ($9.95)
- Understanding Personal Data Security ($4.99)
- Understanding Home Theater ($4.99)
- Understanding Cutting the Cord ($4.99)
- Understanding Digital Music ($4.99)