More HDTV Gotchas to Know by Black Friday

On Tuesday, I talked about some of the gotchas regarding LCD HDTVs and how manufacturers fudge or redefine specs to their own advantage. In this installment, I'll discuss the very basics of handling audio in an HDTV system.

Audio in HDTV systems can be even more tricky and confusing than video. As Mac (and PC) users, we're fairly familiar with video, but simple stereo audio is usually relegated to a pair of analog desktop speakers or headphones.

However, when you move up to an HDTV system, you'll be faced with new terminology, perhaps new connectors, and conventions in the HDTV industry. One could literally write a whole book on the subject, but I'll keep this simple and just cover the highlights -- to help you avoid a mistake.

The Biggest Gotcha

The first thing to know is that, associated with HDTV video are six channels of audio. That's true whether you have a DVR from Comcast, a Blu-ray or DVD disc or an Apple TV. These channels are: front left, front center, front right, Low Frequency Effects (LFE) rear left and rear right. You'll see the term "5.1" which refers to the "5" main channels and ".1," the LFE. It's a weird nomenclature to be sure.

Every HDTV has just two speakers built-in. So if you connect, say, an Apple TV to your HDTV directly, via HDMI, those six (5.1) channels get mixed down to just two speakers. Depending on the TV's audio circuitry, those six channels will still be there in some form, but you'll still get the result from two, tiny, 10 watt speakers along with very limited spatial effects.

This is more or less okay for a den or bedroom where it's inconvenient and expensive to have lots of speakers. It's sufficient to plug HDTV sources directly into the HDTV and select the desired one. But not for your primary living room home theater!

A Real Home Theater

You don't have to have a front projector system, a giant silver screen on the wall, theater seats, curtains and a popcorn machine to have a nice home theater. But what you will need is what's called a Home Theater A/V Receiver. This is a do-it-all box that accepts all your HDMI, component, composite inputs, (plus digital and analog audio), handles the video processing, and sends the video to the HDTV and the six channels of sound to your speakers.

If that sounds expensive, yes, it can be. However, you can start small and grow. There are a wealth of these Home Theater A/V receivers. They vary depending on how many HDMI inputs they can accept (HDMI switching is expensive), whether they can upconvert and scale VHS and DVD sources, and what kind of sound formats they can handle. I would recommend one with a least three HDMI inputs.

Because space is limited, I'll make a recommendation: the Denon AVR-1610 for $379. Plug everything you have into it, and send one HDMI cable, the output, to your HDTV. The TV's speakers will not be used.

Now, here's the fun part. You can start with modest speakers on the front: Front left, front center, and front right. Because dialog is often only on the front center channel, you shouldn't skip that. You can get three matched, consumer grade front speakers at Best Buy for perhaps $400. No need to go overboard here. For those who want something a little better, Bowers and Wilkins, Polk and Paradigm make very nice speakers. Then, over time, add the rear speakers, which can be much smaller and less expensive, and finally a Subwoofer for the Low Frequency Effects. This speaker's output, perhaps 20 to 60 Hz, is the one you feel on your skin.

A good A/V receiver will channel some of those low frequencies to the front speakers, but they're not designed to really go that low in frequency, so you'll hear a muted representation. It's there, but won't knock you out of your seat.

Sound Formats

Most modern Blu-ray players and A/V receivers can handle the modern sound formats. In the early says, we had highly compressed audio in "Dolby 5.1" format, and that's still the broadcast standard for cable and satellite -- to save on bandwidth. However, more and more Blu-ray discs are using Dolby TrueHD and an equivalent competitor, DTS-HD Master Audio. These are uncompressed audio formats that will knock your socks off in a home theater setting.

Last year, you had to be very careful to make sure your equipment could handle the advanced audio formats, but this year, just about all the mid-range and higher devices generate or accept and decode the more advanced formats.


I'm out of space. This has been a very cursory overview. What's important is to be aware of what you'll be missing if you plug all your HDTV sources directly into an HDTV. You'll be living in a shadow world with toy sound that pales, technically, compared to the 1080p video you worked so hard to get.

For a few hundred bucks more, you can buy a decent A/V Receiver and start to add speakers as budget permits. Then, when you watch the new Transformers movie during the holidays, your family will be jumping out of their seats as the audio lights up the room. Considering the investment you're making in HDTV, this better method of handling audio will provide a much better viewing and listening experience.

Think about the actual movie theater experience. The pulsing, vibrating sounds of jets, explosions, and dragons makes for much of the visceral movie experience. Over time, you'll want to add that experience to your HDTV's fabulous video.

Suggested Wiring Diagram

Below is a simple schematic of a beginner sound system and some optional HDTV sources. It just has the front speakers, a good starting point. In time, you can add the rear speakers and the Subwoofer for the low frequency effects.

Questions? All of us who have done this will try to help in the comments section.


HD audio diagram