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

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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.

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

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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.

Understanding Headphone Amps

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[Updated September 9, 2015]

It’s challenging to discuss a home theater category like headphone amps and remain within the practical—and financial—bounds of middle class consumers. Many home theater owners have never even heard of this gear category, let alone own such a component.

However, the value of headphone amps, for people who truly love great sound, can’t be disputed. The good news is that many companies, like Schiit Audio and others, produce affordable hardware that can dramatically improve the quality of your sound when you’re wearing your cans and enjoying your favorite album (or movie).

The following is an excerpt from my book Home Theater for the Internet Age, from Chapter 9: Headphones.

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Curt Robbins


Headphone Amps

Headphone amplifiers are probably the single most misunderstood area of audio entertainment (if you’ve even heard of this tech). Infamous for being expensive toys owned by audiophiles, they are a relatively uncommon device within a home theater. What does a headphone amp do? Simply put, it’s an output from your receiver that re-amplifies the signal to improve the sound produced by your headphones.

In most receivers, even high-end models, the built-in headphone amp is a super-cheap afterthought. Audiophiles and music enthusiasts claim that, if you have a good pair of headphones, you’re cheating yourself by not getting at least an entry-level headphone amp to bring out their potential. “Using a dedicated headphone amplifier will step up the performance of any home theater to an entirely new level,” Frank Iacone, a 35-year industry veteran known for his heartfelt Twitter feed and reviews on headfi.org, told me in an interview. Because most middle class consumers have never used a headphone amp—and very possibly never listened to high-end headphones—it’s one of those situations where people simply don’t know what they’re missing.

OPPO HA-1 headphone amp for twitter - 2

Prices for headphone amps range from $60 to $16,000. That’s right, if you have a large pile of money and are wondering what to do with it, you can purchase 3,200 copies of this book or a headphone amp that costs more than an entry-level Toyota. The kids can walk, get the amp!

Tube, Solid State, & Hybrid

There are two primary technologies employed in building headphone amps: Analog vacuum tubes and digital solid-state circuitry. Vacuum tubes are way old school; some audiophiles collect antique tubes that are more than 50 years old. Solid-state amps, which involve digital processing and circuitry, are typically less expensive than their tube-based brethren and feature a more accurate, less “warm” sound. The third type of headphone amp, called a hybrid, merges these two technologies, theoretically offering the best of both worlds. Good applications of this approach achieve this, while poor executions fail to sufficiently exploit each type’s advantages.

Audiophiles Divided

The audiophile community is divided regarding which approach, tube or solid state, provides nicer sound. In reality, each type offers distinct pros and cons and is implemented in a wide variety of quality levels by different manufacturers. In the end, the model best for you is determined more by your wallet than your feelings regarding the warmth, intimacy, or accuracy of a particular model’s amplification technology.

However, one typically doesn’t spend the kind of money we’re talking about on headphones and headphone amplifiers and not appreciate the nuances of high-end audio. For many, the differences in sound quality between comparable quality tube and solid-state amps is significant (another religious war among audiophiles). My own opinion, quite frankly, is that I appreciate the lower cost of solid-state amps while also somewhat desiring the more accurate sound reproduction and efficiency that they deliver (which I also prefer in my AV receivers). But this certainly doesn’t mean that solid state is better. It’s simply my personal take on the matter (and my wallet’s influence).

From a sound perspective, I’d rather have a $1,200 Woo Audio WA2 tube amp (pictured below) than a $120 Vali solid-state model from Schiit Audio. However, this reflects a desire for a high-end amp, not a disdain for digital amps, preference for tube amps, or any leaning toward Woo Audio over Schiit (both of which are great companies offering models you should seriously consider). My budget—and the quality of my headphones—dictates that my purchase will probably involve a cold aluminum solid-state Schiit Audio Asgard 2 for $250 (the “practical” model for which I continue to lust).

Woo Audio WA2 for blog

Pros & Cons

One disadvantage of tube amps is that they can require up to 10 minutes to heat up in preparation for use. This is an old school characteristic indeed, and about the most retro electronic wait period of our modern drive-thru, microwaving, Twitter filled world. Fans of tube tech, however, swear it’s worth the patience and dollars (and boast of the romantic glow provided by their vacuum tubes—probably especially nice during the holidays).

An advantage of solid-state amps is a reduction in background noise. Some audiophiles actually prefer an elevated background noise level, especially for live performances or fully analog productions. One advantage of solid-state amps that doesn’t really touch home theater applications is mobility. Some models are designed to accompany a mobile device, offering small size, battery power, and significant improvements in audio quality compared to the anemic default output of mobile gadgets (especially when paired with good headphones).

Upgradable Tubes

A neat feature of vacuum tube amps for hobbyists is the fact that you can swap out—and thus, upgrade, within certain technical limits—the tubes. Some hyper-hobbyists even keep two or three sets of tubes, reserving each for a particular type of music. Many replacement tubes are relatively inexpensive (Schiit Audio sells a set of four tubes for its $350 Valhalla model that runs $40). While the cost of the initial amp itself might be somewhat hefty, the expense of playing hobbyist with different tubes—or replacing units that have burned out—can be manageable and fun.

Reputable Brands & Models

What is more important than whether a headphone amp employs vacuum tubes or solid-state circuitry is its sound quality, period. Companies such as Woo Audio (USA), HiFiMAN (USA), Bryston (Canada), OPPO (China), and Schiit Audio (USA) offer a wide range of both tube and digital amps.

Woo Audio manufactures expensive tube-based models featuring exquisite hand-crafted build quality and leading edge design that are made in New York City. Ranging in price from $550 to $16,000, Woo offers some of the best (and most attractively designed) tube amps money can buy. If you’re sweet on their products but on a budget, consider the $600 WA3 or $700 WA6.

Schiit Audio, headquartered in California, produces beautifully sculpted aluminum amps. Most of their models are solid state, but they also offer a couple hybrid and tube models. Schiit amps perform like Canadian and American models costing several times more. It’s relatively small product line, priced between $100 and $750, are all American made from American parts (Schiit even has face-to-face relationships with its local vendors). The company provides what reviewers cite as excellent and personalized customer service.

Shiit Audio Valhalla for blog

Premium Blu-ray player manufacturer OPPO in 2014 released a $1,200 solid-state headphone amp that has received rave reviews. The audiophile-quality OPPO HA-1 features an attractive display that compliments the unit’s leading edge features (it can even simulate those sexy analog VU meters from way back when). Like other OPPO products, the HA-1 is controllable via the OPPO Remote Control App for mobile devices.

“The hardware inside the HA-1 are some of the beefiest I’ve seen in a headphone amp. It looks like a barely scaled down loudspeaker amp,” said Geoffrey Morrison when reviewing the model for Forbes. Reviewer John E. Johnson, Jr., writing for hometheaterhifi.com, added, “And, wow! What a sound. Built like a tank, and gets as hot as a tank in the Sahara due to its Class A output.”

If you want to check out entry-level tube-based headphone amplification on a budget, look into the Bravo Audio V2, a $70 ($55 street price) single-tube amp. “It’s a nice little tube amplifier in its own right for those of us who want to experiment with that highly desired ‘tube sound’ without paying the exorbitant rates many tube amps cost,” said an amateur reviewer on Head-Fi.org.


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.