Common Confusion in Home Theater: Part 1

3d1There’s quite a few topics in home theater that are confusing for the average consumer. From volume levels on modern AV receivers to firmware updates to distortion, these topics make the purchase, installation, and enjoyable use of home theater gear both intimidating and sometimes perplexing. In the next few posts, let’s clarify some of these issues.

The following is an excerpt from my new Kindle book Home Theater for the Internet Age. The other blog posts in this series are listed below:

  • 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 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 room dynamics
  • Part 9: Ethernet, component separates, and broadband internet routers

curtsig2 - trans
Curt Robbins


Volume in a Zero dB World

The volume, or intensity, of sound produced by a receiver or amp is expressed in decibels, or dB. The “bel” part of the term is in honor of Alexander Graham Bell, because decibels, as a unit of measure, were developed to objectively determine audio levels on the earliest telephone networks (and you thought it was all about jet engines and 1970s rock concerts by The Who….).

What is confusing about decibel readouts on today’s receivers—and has been in practice for only about the past decade or so—is the zero dB system employed. It’s inherently counter-intuitive. Basically, on the dB scale, zero (0) represents the receiver’s loudest output (if you turned up the volume to the maximum possible). You’d obviously have to decrease the volume to enjoy it at a reasonable level. These enjoyable volumes occur in the negative numbers. A reasonable zone might be -32, or maybe -25 (depending on the input source and your room). But it will always be expressed as a negative number. Because we’re talking about negative numbers, smaller numbers (ignoring the negative sign) equal higher volume levels (-10 will be much louder than -35). And this is where the confusion arises.

pioneer av receiverThere is a logic to this scheme, however. In the past, when higher numbers equaled greater volumes, the settings were entirely arbitrary, with wide variations among receiver manufacturers. One company might demark 1 through 10 (one being the softest, 10 being the loudest), while another would get more granular, adopting a 1 through 20 or even 1 through 100 scale. It was the wild west. The problem was that there was no objective way for a receiver to display to its owner the volume at which it was producing sound.

Zero dB originated in the commercial broadcasting and recording industries. On your home theater’s receiver, think of 0 dB as the tipping point for distortion and where you may begin encountering things like “clipping” (jarring cuts and dropouts in the sound) and other signs that the receiver is operating beyond its capacity to provide clean sound. Depending on the quality of your receiver, you may experience distortion at a volume below 0 dB. But a good unit won’t begin distorting until this point (a valuable litmus test when researching your purchase).

The specific dB level indicated by a receiver is still somewhat subjective. In addition to your receiver, your speakers and the room in which they reside significantly influence the actual volume at which you hear the audio reproduced. Take this number displayed on your receiver lightly, realizing that -25 dB with your old speakers or on your neighbor’s system won’t sound exactly the same on yours (but it should be in the ballpark).


Updating Firmware

A hardware component’s firmware is simply updatable software stored on a chip in the device that controls certain features and functions. Because players are basically audio and video-focused computers dependent upon complex decoding and processing software, manufacturers often release firmware updates that expand or enhance the functionality of their units—or fix existing bugs. It’s a good idea to keep the firmware of your home theater devices, specifically your Blu-ray player and AV receiver, up-to-date (check manufacturer websites on a regular basis).

The biggest reason to update your Blu-ray player firmware is to ensure that it can properly play the latest movie releases. Hollywood is continually revising copy-protection standards in an effort to thwart piracy. Sometimes new protection schemes can’t be recognized by a particular player (especially older models)—resulting in a movie that won’t play. Instead of having to purchase a new Blu-ray player (a ludicrous proposition at which consumers would obviously balk), you simply need to update your firmware to match the latest copy-protection encryption standards of new-release movies.

oppo bdp-103Depending on whether your Blu-ray player is connected to the internet, there are a variety of ways firmware updates can be applied. If your player features internet connectivity, simply follow the manufacturer instructions to obtain and install the update files. If your player lacks connectivity, you can download the files from the manufacturer website using a Windows or Mac computer and copy them to a USB flash drive. The USB drive is then inserted into the player to begin the installation of the update.


Disadvantages of Blu-ray

The biggest disadvantage of the Blu-ray format is that some discs can take a while to load (up to a minute or two), depending on the speed and quality of your player. This wait is so much greater than for DVDs that, on some titles, new owners sometimes believe they’ve run into a bad disc or that their player has locked up. More expensive and newer Blu-ray players feature faster processing chips, decreasing your wait time as the disc content loads into the memory of your player. If load speed is a concern, remember to demo, demo, demo. (For you geeky types, the Blu-ray video format transfers data at roughly 40 Mbps, which is why you can’t yet stream an uncompressed Blu-ray video over your internet connection.)

Models known for their speedy load times include OPPO’s $500 BDP-103, its $1,200 105 model, and the $400 Pioneer Elite BDP-62FD. Personally, my first choice would be the BDP-103 (pictured above). Those on a budget might prefer the BDP-62FD, which is very comparable to the entry-level OPPO (but not quite as powerful or refined).


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.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s