Home Theater Focus : Tech Advice

TV on the Net

Fri, 04 Aug 2006 17:52:00 GMT

This link has been going around lately so I decided to chime in with it because it’s very good guide. It also verbalizes the state of TV/IP as we stand today. It’s Jeff’s Quick Guide to TV on the Net (TV/IP) found on Jeff Pulver’s Blog.

Among the commentary it contains one of the most comprehensive lists of television available for viewing online here and now. The technological groundwork for IPTV is quickly coming into view. That such a complete list of programming is already online means the phone companies are probably jumping on IPTV at the right moment. Since there is already some built in competition to TV on the 'net it'll be interesting to see how it all pans out. Unfortunately it’ll probably be through more restrictions, more flags, more DRM and programming blackouts.

Phone companies are promising its broadband services will topple CableTV as the default choice. Strong words from AT&T’s Ed Whitacre punctuate the phone company’s intentions with a bit of in your face attitude. Many of the networks outlined in Jeff’s guide are already restricted by DRM and content management, meaning you can’t get some of the streams from certain locations unless you pay. It’s as Morpheus said: “Welcome, to the real world.”

The biggest disaster with a direct relation to regulated television and HD content available online is the situation the Net Neutrality bill seeks to curtail.

DRM: The Business end of Digital Media

Thu, 13 Jul 2006 18:30:00 GMT

In our last look at digital media we covered some of the oldest formats including the ever present MP3 and Apple's AAC. The AAC file is Apple's codec based on the audio/video compression used by MPEG or the Moving Picture Experts Group - version 4. Another style of codec that emerged to compete with Apples AAC was from - you guessed it Microsoft who went in a different direction than borrowing from the MPEG. Delving into the competition between WMA and AAC brings us smack into the middle of a market war and the highly volatile DRM issue.

WMA: Windows Media Audio was brought to you by those wild and crazy guys from Seattle. This is Microsoft's proprietary audio file format initially developed to compete with the MP3 but has wound up a competitor to Apple's AAC. In the digital music business right now iTunes is king and Microsoft would like nothing better to jump in and knock Apple of its perch. WMA is supported by Windows Media Player software that is used on Microsoft Windows operating system. But the technology has been licensed out to a wide range of devices like DVD players, MP3 and any other kind of portable media players you can imagine including cell phones. Apple's iPod does not support WMA - go figure!

WMA doesn't include DRM (digital rights management) which is a layer of software that prevents you from copying media files (like songs) from one device to another. However, WMA streamed through the latest version of the Advanced Systems Format (ASF) container does have a DRM called PlaysForSure, codenamed Janus also called DRM10. This is Microsoft's answer to Apple's DRM which is called FairPlay.

DRM: Digital Rights Management is a sad fact of digital media today. It's designed to protect the artists and record companies from endless duplicates of their intellectual property from being distributed freely. Two of the most common places you'll confront DRM in digital music is from in online digital music sales.

iTunes: Apple's iTunes is tops in the industry. One estimate puts its share of total internet music downloads at about 72%. Individual songs downloaded from iTunes cost .99 cents and each song you download is encoded with Apple's FairPlay DRM. There is a list of restrictions over the song that you download. What it all means is that even though you own the music you purchased from iTunes, there are rules. This has ticked off a lot of people and lends itself to the question, do you really own it? The answer according to the RIAA is no.

Subscription Services: To compete with iTunes a clever new business paradigm has emerged called subscriber music services. Using this scheme you agree to a monthly fee and during that time you have unlimited access to the services library of typically one million songs. These songs are encoded with Microsoft's DRM called PlaysForSure or DRM 10. You can play these songs back on Windows Media Player 10 or copy them to any portable device that is PlaysForSure compatible. More and more devices are jumping on board all the time, names like Archos and Creative make portable media players that will playback your subscribed music. Some of the first included Napster, Yahoo Music and MSN Music. Today there are many more one is even exclusive to a piece of hardware called the MusicGremlin.

So far, the Apple camp dominates with iTunes but the Microsoft DRM10 / Windows Media Player camp are a distant second with the subscriber paradigm. The failure of subscriber music to overtake significant ground on iTunes is often cited as proof of a truism in today's digital media. People are willing to subscribe to their TV and movie programming, but they want to buy and own their music.

But bear in mind that the subscriber music business is still relatively new and many just don't understand it yet. If you're a typical listener who likes popular music and use a mobile media device it should be a good fit. Would you rather pay $12 bucks to get 12 songs from iTunes, or pay $12 bucks for access to a million songs on Yahoo Music for one month? There is an alternative - a Russian music service known as www.AllofMP3.com, one of the webs best kept secrets. AllofMP3 blows away any of the others in price and quality. You can choose the bitrate of MP3 you desire and can even buy your media in lossless formats.

So, which online music service do you like?

Understanding Digital Media Formats

Mon, 10 Jul 2006 20:33:00 GMT

Have you ever tried to make sense of all the different types of digital audio and video? Ever thought of creating a digital media library of your own but feel a little overwhelmed by all the formats? Welcome to the first installment of a series that looks at digital audio and what it all means to you. Who can deny the convenience of storing your entire library of music in something size of a cigarette pack? But some digital audio formats can backup CDs in audio quality that rivals (or duplicates) that of the original, while others are about as pleasant as cat piss under the couch. The first step in understanding digital media is to know your codecs.

Digital audio formats are actually codecs. Codec is a portmanteau word or a word originally made up of other words - like brunch. Codec comes from Code - Decode which is what's happening when someone rips (encodes) a CD into another digital format and then listens to it later (decode). Here's a quick outline of many of the most popular codecs.

Real Audio: RealPlayer has been around a long time. You may have clicked an audio or video stream that prompted you to install the Real Player codec on your computer. It's used mainly for streaming media from a website or internet radio. It’s a low bandwidth encoding method so it won't sound very good, not a problem for a student wanting to hear a recording a famous speech by JFK. Its strength is that it can stream music through the web even under adverse conditions such as dial-up. But if you care about sound quality there are better codecs.
WAV: Short for wave. This format was created by IBM and Microsoft years ago and has annoyed Windows users with bleeps and blurps ever since. It's not suitable for encoding digital music because WAV files are too large. WAV is sometimes worthwhile as a temporary step when transcoding. When you want to convert a digital audio file to another format but the codec won't recognize the format your digital music is in, you must first convert it to something your codec can see. WAV is so ubiquitous when using Windows that many codec tools will read it and can encode to it.
AIFF: This is the Apple equivalent to a WAV file. It has the same disadvantage as WAV in that it produces very large files.
MPEG: Pronounced M-Peg, an acronym for Moving Pictures Experts Group. The MPEG produced a family of codecs that ushered in the golden age of digital media compression we now enjoy. The groups' codecs are used on DVDs, digital radio, satellite and cable TV and through the internet. MPEG consists of a coalition of companies interested in high quality compressed audio visual media including: Dolby Labs, Fraunhofer (FhG), AT&T, Nokia and Sony.

Mpeg Details

MPEG developed the first widely adopted lossy audio video compression, MPEG version 1. Lossy compression simply means that after the audio or video is encoded the result is a relatively small file with minimal loss of quality. When we're dealing with something like an MP3 (or AAC) the loss of fidelity is proportionate to the amount of compression applied and measured in bits per second, the more bits per second the more data in the file hence higher quality. Smaller files result in greater loss of fidelity and therein lay the rub in dealing with digital media.

A 128 kilobit per second (kbps) MP3 is a nominal amount of compression and average for what you'll find online at sources like iTunes. 128 bit MP3s fit nicely through the internet and has an audio quality that sounds acceptable through most earbuds played back through the average portable player. But to the discerning ear played back on a home theater audio system a 128 bit MP3 is the acoustic equivalent of unwrapping a Little Debbie snack cake at a fine dining establishment.

MP3: The MP3 was derived from the first version of its codec Mpeg1. MP3 is by far the most popular format of digitally encoded music. The .mp3 file is the most widely used digital audio format on the internet. Nearly all portable digital media players can playback an MP3 as it's the first real breakthrough in lossy audio encoding, MP3 is also known as MPEG-1, layer 3.
AAC: Advanced Audio Coding is the audio core of the Mpeg-4. This is a more advanced audio codec than the MP3 which is derived from Mpeg-1 and its most commonly used by Apple in its iPod which can read AAC files. As a more advanced codec you'll get slightly higher fidelity at a slightly lower bit rate.

Next we'll delve into more Digital Audio codecs and explore of great interest to audiophiles there are a few that are lossless.

Center Channel Speakers: Part 2

Mon, 15 May 2006 21:26:00 GMT

It's a cliché that's worth repeating.

The Center speaker is the most important speaker in your system for Home Theater.

Look around the local retailers and web dealers for speaker systems. You'll find most 5.1 speaker systems build a center speaker that matches the other speakers in the system, about the same size drivers etc. Some speaker systems will give you the option of larger front speakers. For home theater this isn't necessary, although larger speakers with larger woofers can produce deeper bass the speaker should be set to "small" in the receiver. The small setting means that sounds below the crossover frequency will be diverted to the subwoofer. A typical crossover is 80Hz. So, the front speaker won't produce any of the lower bass instead those sounds will be diverted to the subwoofer. If you have a competent sub in your system the effect of setting your speakers to the "small" setting will produce more bass. We won't delve too much into bass management, that's another topic. Suffice it to say that for Home Theater it's a good idea to set all your speakers to "small" even if you like to switch it back for dedicated two channel (music) sources.

The center speaker arrived back in the days of Dolby Pro-Logic. Dolby Pro-Logic was the improvement on Dolby Surround that had a problem with hard to hear voices. By giving the midrange its own dedicated speaker dialogue in film could now compete with splashy sound effects and musical scores that dominated the front and rear speakers in a surround system.

The center speaker is responsible for reproducing sounds in the range from about 500 to 5000 Hz. This isn't a hard limitation of the center channel just an estimate of the midrange. In a 5.1 system the center channel can receive sounds from any frequency.

There is a lot going on in that center channel. Not just voices but a lot of sound effects too. Virtually anything that goes on front and center to the camera's perspective can be heard through the center channel. A frail center speaker will rob explosions, gunfire and all those other splashy effects of the bang they should have, despite the big sub and giant front left and right speakers.

One of the most common complaints when you have a center speaker that isn't up to the task is muted voices. Dialogue gets drowned out when the action or musical score gets loud. Chances are the center speaker isn't able to produce enough midrange or the midrange has some dispersion problems which can be associated with the speaker's build.

Sound Speaker Build Quality

One of the classic "cheap" center speaker builds is the MTM (midrange, tweeter, midrange) build. This is a two way design. One tweeter sits between two woofers. Since this design has no midrange it's already off to a bad start. To make an effective center channel speaker of this design is a challenge to the speaker's builder. The design opens you up to acoustic dispersion problems called the lobing effect.

Lobing is a bend in a circle. The circle of sound from your speakers should converge on the audience. But if your center speaker is exhibiting lobing it's difficult to accurately judge the sweet spot. The net effect is the midrange suffers.

Look for a center channel speaker that has a midrange and tweeter stacked on top of each other with woofers on either side. This is a three way design and isn't usually found in the most budget speakers. Most manufacturers only build their top end center channel speaker in the desired three way design.

Not to pick on Paradigm, a fantastic Canadian speaker manufacturer. But you must go well up Pardigm's product line to get into a three way center. If you can afford it you'll be glad you did. The mainstream line is the Monitor series, they're an excellent buy. But the CC-370 (pictured at the top) is an MTM design. I have not auditioned them or put them through the test. To really determine if they exhibit lobing problems you'd have to try it for yourself in your own livingroom. But I would automatically avoid that speaker when looking to spend a bit of money on a quality design.

To get the three way design you have to go two rungs up the Paradigm ladder to the CC-570. The 570 is part of Paradigm's "Reference" series of audiophile quality speakers. The 570 is an amazing speaker that will knock you back into your seat. The CC-370 is a $300US speaker where the CC-570 retails at almost a grand.

Think of it this way, a center speaker should include a midrange! A real center will make a dramatic difference for movies. For two channel music (CD, MP3 etc) it can only serve to fill in the central soundstage, not exactly a critical job if you have well positioned front speakers. But, if you've upgraded a two channel stereo to 5.1 surround for Home Theater and skimped on the center speaker reasoning you'll upgrade it later, you might be wondering why some soundtracks seem robbed of oomph and sometimes dialogue is a bit thin. Well, later is now.

Center Channel Speakers: Part 1

Fri, 12 May 2006 18:31:00 GMT

Today Home Theater in a box solutions are being snatched up like sticky rice banana leaf rolls at a Dim Sum buffet. These are specialized systems specifically for Home Theater application. You'd think we'd have better acoustic answers for such a specialized market space. But it seems the crucial center channel is no better off than it was in the days of the Pro-Logic add-on units. We'll take a closer look at the history starting with part one of the Center Channel Speaker.

A market shift in home audio was probably complete years ago. The shift was away from hi-fi / stereo and into Home Theater. Today you almost never hear about hi-fi or stereo (except in car audio) because Home Theater has taken over.

Let's step into a time machine and head back to the mid 90s. Back in this day Dolby Pro Logic add on systems were the new thing in home audio. Grunge rock had fully eclipsed the glam inspired big hair metal of yesteryear. A saxophone playing president was creating budget surpluses and something called "alternative" was now a mainstream style of music. Electronic sounds were also beginning to filter into the mainstream as the rave sub-culture was in full swing.

Home Audio was still home stereo but affordable receivers armed with Dolby Pro Logic surround sound started to get popular. These new systems could decode your favorite VHS tape and create center and a rear channels. Most people that were into hi-fi at the time (the obvious market for the new but as yet undefined Home Theater market) already had a stereo system.

Back then a "good" stereo system meant a system anchored by a quality receiver or integrated amplifier. Kenwood, Marantz, Pioneer are big named that made some historic receivers that were designed with a build quality the like of which is now extinct except in a very small market.

This was a common statement back in the mid 90s.

"I've had this kick arse receiver since the early 80s. There is no damned I am going to pay $300 + to replace it with one of these flimsy Sony receivers because it's got a "pro-logic" logo on the front!"

And so it was the add-on becomes the order of the day. The add-on was a clever way to add three more speakers to your system. All you had to do was engage and external processor loop or a tape monitor function and BAM instant Dolby Pro Logic.

What went along with the new Pro-Logic add-ons and sadly many receivers were the smallest cheapest "quick fix" speakers you could find. Nobody could blame you if you were under whelmed by the quality of surround sound in the home. What was to blame was the tiny drivers in these little speakers.

Maybe a smaller speaker made sense for the limited range of frequencies being played through the rear channel. But the center channel in these systems, although also limited in range were going to reproducing sounds our human ears hear the most. There is more information on a movie soundtrack coming from the center channel than any other. The center was intended to reproduce dialogue between actors in your movie. It would also reproduce sounds in the midrange and any action that occurred front and center. A stereo system with a cheesy surround add-on was doomed to mediocrity.

Sadly HTIB solutions proves what Sting once said.

"History will teach us nothing."

Next week I'll delve into the importance of the center channel speaker.

Connect your iPod to Xbox 360

Wed, 21 Dec 2005 21:12:00 GMT

The Xbox 360 is fully iPod compatible with correct download from Xbox Live. Unless you’ve been downloading your MP3s from iTunes without stripping them of Apple’s DRM, FairPlay. A FairPlay MP3 won't play through Xbox 360. Apple and Microsoft are incompatible, go figure.

Here is exactly how to go from this:

Xbox 360 with iPod connected to one of its two available front USB ports.

To THIS:

Mind blowing psychedelic music listening bliss with a high definition laser show pumping to your own playlist.

First stop is Xbox Live. This is the online service that may just be the online shopping wave of the future. Here we have my account on Live ready to login to the Marketplace. This is the shopping mall according to Microsoft. Don’t laugh, shopping by remote control from your couch is going to seem very normal very soon.

Once inside Live you can navigate your way to all kinds of free goodies. Many of the downloads cost Microsoft points which are purchased with your credit card. But there are enough freebies to make it interesting for the cheap among us. Including this little gem.

Here’s an handy app developed by a third party Nellymoser that allows XBox 360 to play with your iPod. It’s a free download from Xbox Live, costing no points just download and install on your 360’s hard drive. You did get the one with the hard drive didn’t you?

Here’s a look at what Nellymoser does to your Xbox 360's Media Blade, a new music playback device at the bottom. Except you'd see YOUR iPod (not mine).

Sitting back in front of your telly you get to all these swell controls over the iPod. Look, I'm browsing 20Gigs of musical bliss.

Play a song and hey look, you get a visualization just like using Windows Media Player or a Winamp plug-in. Okay, call me a hippie but the full screen visualization has provided me with hours of entertainment while I listen to music.

And yes, my mind is fully blown now. Sorry all you competitive gamers there are no Achievements to be had for wasting time listening to music with the visualization on. There should be, but only if you have taste. Rocking your vis to Nelly or Jessica Simpson doesn’t’ count. There you have it. Full screen that baby with the letter X and away you go! It's the 60's all over again, only cooler.

LCD vs DLP; the choice is yours

Mon, 08 Aug 2005 16:38:00 GMT

From a viewers perspective there is little difference between the two display types. I won’t get into the exact technical differences between the two devices. But there are many who find themselves at the local TV shop wondering which one they should buy, both have had significant drops in price lately and rumor has it that there is going to be more before the Christmas season this year. Today’s 720P DLP and LCD rear projectors are no longer priced out in orbit, comparable deals can be found on both. Both technologies are very good at what they do with only subtle differences in appearance it can be an intimidating decision trying to figure out which to buy.

Sets like Samsung’s HLP4663W is a very good 46” DLP set based on TI latest series of DLP processors. Sony’s GRAND WEGA line of LCD rear projectors like the KDFE55A20 makes for good competition from another display technology. You can drive yourself crazy driving to more and more TV shops looking at more different sets to see if any of them are going to have that magical quality that your eyes love.

My advice might differ from the orthodoxy you’ll get on many forums or even sales people who say to compare, compare, compare and trust your eyes. Outside looking for a few specific details on a new TV, I don’t think viewing more TVs in store are going to do you much good. Sure, you can see with your eyes standing in the store that the CRT based Rear Projectors (RPs) sometimes have color alignment problems, but can you really trust the TVs are even calibrated correctly sitting at Best Buy? Even the high def feed from the local cable company that’s piped into an aisle of hi-def TVs might be sullied from being split too many times. I’ve seen DVD players connected to display model TVs with a movie and the DVD player isn’t even setup to play at progressive scan, so the resulting image is horrible. So, I don’t think you’ll get much out of looking at displays in the store.

But when deciding between LCD and DLP do some critical viewing, knowing what to look for in each display type will go a long way in helping you decide.

Look at both TV types from a direct viewing angle, mimic being seated in front of the set, bend down on a knee if you have to. All rear projector displays are designed to be viewed straight on. This may seem like a limitation until you consider the average size of the family room and how huge these TVs get. In your average viewing room a 50” set is going to loom so large it’ll hard NOT to see it straight on.

On the DLP make sure you watch something moving quickly across the screen, like a dogfight between two planes that scream across the screen, follow them with your eyes. You can just flick your eyes across the screen while watching anything. Do you see the rainbow? If the rainbow effect is disturbing LCD is your option. The rainbow effect is caused by the color wheel that presents equal amounts of red, green and blue to create all the colors you see. If you move your eyes with the color wheel you’ll probably see the rainbow. There is a percentage of the population who will see this rainbow all the time. These people’s eyes aren’t easily fooled by technologies optical illusions and they probably have very good eyes.

When judging an LCD, look directly at a particularly bright image, lots of bright sand or white snow. Does it look to you like you're viewing the images through a screen? This is the screen door effect found on LCD projectors. The screen door is caused by the spacing of each pixel on the LCD chip being amplified across the projected surface. That handful of microns of space on a chips starts to get noticeable when projected to 50” or even 70”. There are various tricks done with lenses and mirrors in newer LCD RP designs to alleviate this symptom but a certain amount of it is inevitable. Between each pixel must run a circuit trace, even on the tiny IC chip that is the LCD, the circuit trace regulates voltages to activate the LCD itself.

Those are the drawbacks with each device type. Otherwise they're both great with nice, bright digital images. Both will require lamp replacement from time to time which can about $300 but shouldn't need replacement for about 2 years or so. The DLP has a "color wheel" inside, but this should be no louder than the fan that cools the lamp. So, listening to each TV is important, you want to hear silence. Well... neither will be completely silent because there is going to be a fan, on the DLP a color wheel spinning but you probably won't even hear the color wheel. Otherwise it's up what you like the best. Don't be too concerned about the macroblocking effect when looking at those HD digital cable feeds at the stores. All sets will do this, it's not the sets fault, it's the video.

Good luck and happy viewing.

Power Conditioners

Mon, 27 Jun 2005 03:36:00 GMT

Here's what I've had to say about power conditioners/expensive surge suppressors in the past, it’s still generally good advice. These days at every electronics superstore in North America you can find Monster Cable peddling surge suppressors that may make other bold performance claims like line filtering. Peripherals like surge suppressors, extended warranties and interconnect cables are usually marked up considerably and how the big box stores make money off the sale of very low priced hardware. But do you need surge suppressors or power conditioners?

The quick advice on surge suppression is to that it is a very real factor for electronic equipment. Light strikes near your house and it can send high current through your wiring and can damage equipment. Although relatively rare it can happen. Surge suppression has a rating system in place so a suppressors effectiveness can be measured. Look for their rating in joules; the better they are at shunting a surge to ground the higher the joule rating. If there is no such rating, it’s not a surge suppressor and doesn’t conform to IEEE 587 standards. If you own your house, consider surge suppression on your fuse box to protect everything in your house at once.

As for many of the other claims made of many of these devices, such as line conditioning, voltage or ground stabilizer and noise filter, you must be more than a little skeptical. None of these jobs have a standard (like surge suppression) or a universal rating to measure effectiveness. You must basically trust the manufacturer and in the case of Monster Cables they’ve proven to be quite untrustworthy.

I tend to believe much of the noise about power conditioning is fiction. Consider exactly what job you're looking for and why you need it. Voltage stability can be a problem if you’re suffering frequent brown outs and you have gear that is very sensitive to fluctuations. The owners manual can usually let you know. But most moderately priced electronics gear have power supplies capable of shrugging off minor surges and voltage irregularities.

Keeping your AC pure for better quality audio is the kind of thinking that borders scam and usually is. If your sound is being affected by dirty power and not filtered out by a decent quality power supply, it’s usually in extreme cases only and temporary. Turn your vacuum cleaner on while watching a movie and see what I mean. If the vacuum cleaner is operating in close proximity to your HT hardware the motor’s oscillation will reflect back through the AC line and will likely cause disturbances in your TV’s picture and might even be heard through your audio system. But this is an obvious problem. I get annoyed at the idea that there are minor irregularities on my AC line that I don’t even notice and an expensive power conditioner is going to filter it out and unlock never before heard performance in my audio system.

Bass Management; bitstream/pcm

Fri, 10 Jun 2005 05:15:00 GMT

Bass management problems include trying to get your CD player to use your sub, or having way too much bass coming out of your dainty rear speakers when you use DVD-Audio or SACD driving them to Hades.

If your main media player is a DVD player, be sure it’s set to bitstream and not PCM if you want the use of the rear speakers and sub. At least be aware of where this is set and get to know it well. For greater audio fidelity some like to set PCM when listening to two channel sources, it ensures an uncompressed listening experience, but will often do without some of the effects you demand when watching DVD movies.

There are many differences between bitstream and PCM, usually DVD players are capable of both but CD players are generally only capable of PCM. Without delving into bit and sampling rates the short of it is that Dolby Digital and DTS both sample at higher bit and sample rates (than PCM) but then they compress it, which is a sin to the audio purist. PCM is a slightly lower bit/sample rate but uncompressed. DTS uses less compression than Dolby Digital and that's why it's usually considered superior.

To use my favorite analogy FOOD: PCM is a good diner that serves beer. The PCM waitress brings a steaming plate of delicious food and a cold beer. Nothing fancy but it does its job. That's PCM.

Bitstream is if went to a really fancy restaurant, and they bring this amazing culinary delicacy to your table. But before you can eat it, the waiter picks up the food from each dish and grinds it together with his bare hands letting the pieces fall back onto your plate. Then he bids you bon apitite as he walks away. That's bitstream.

What does this mean to you ask? Part of what makes "bitstream" so fancy and certainly a MUST HAVE on your DVD player, is that bitstream audio encoding methods like DD and DTS aren’t just raw music, but carry encoded instructions along with the audio. Commands for when the sub should kick in and when rear speakers should be used are included. PCM is just two channel music, it can only “tell” left speaker/right speaker what to do and when to do it just like stereo has been doing for decades. It’s “pure” but there’s no fancy surrounds or sub being commanded explicitly (discreetly) by the audio signal.

That said, one would expect to get no sub or rear speaker action when listening to two channel PCM CDs. That’s not necessarily true thanks to Dolby ProLogic, Pro Logic II, DTS neo-6 and other methods of creating a multi-channel “matrix” from two channel information. If you notice your rear speakers kicking in while listening to CDs it’s probably has Pro Logic II enabled. This brings us back to bass management.

The typical Home Theater receiver bass management setting is the small speaker/large speaker settings. The DVD player might also have the same setting. With small speaker enabled, you’re setting a crossover, or a crossover frequency, that’s the frequency cutoff to the speaker you’ve set to small. Sounds equal to or less than the crossover frequency will be redirected to the subwoofer. You should only choose one component to handle the bass management, two components setting a crossover will likely cause you to lose some of your bass. Read your documentation to see which component actually publishes their small speaker crossover frequency and then decide which you want to use.

Set your front (main) speakers to “small”. The small speaker setting is admittedly an ambiguous bass management setting but it’s very common on low to middle end quality. High end bass management systems will allow you to set the crossover frequency. On the ambiguous “small speaker” setting a typical crossover is 100hz. That means all parts of the music that are 100hz or lower go to the sub. If the fronts are set to “large” 100hz and less are going to the fronts and nowhere else.

You might have some fine front speakers you’re particularly proud of and would feel ashamed to call them small. But remember, we’re talking about speakers here, not condoms. That 100hz might be replicable by your front speakers, but even big high end fronts can’t reproduce those low freq’s at volumes your sub can. Many bookshelf speakers are rated to 40Hz… SCHYEA! If you look at the freq range of most speakers mapped out on a graph you’ll see that db tails off significantly in the low end.

There are third party solutions for bass management. One of the most popular is the Grand Moff Tarkin of bass management utilities called the Outlaw ICBM. This baby allows you to set explicit crossovers to all speakers in your room. It’s the “ultimate” in bass management. If your receiver is light in the bass management department, and you want the high end way to control bass in your system but don’t want to spend high end money, a dedicated bass management component like Outlaw’s ICBM is the way to go.

Stacking Components

Tue, 07 Jun 2005 03:49:00 GMT

I get asked some good questions in the forums and this one deserves some elaboration. To paraphrase:

Is there a proper stacking order for hi-fi components you have lay on top of each other?

Someone that has never owned a component hi-fi system before, might have difficulty deciding which components to lay overtop of which. Stacking them is usually inevitable, most people don’t have that many shelves that each has its own slot. However there are many open shelving units that have a shelf per component and leave all components open to the air. The basic design flies in the face of the more “entertainment center” conventions that had everybody stuffing their audio gear into a cabinet. These days it’s a sort of modern addition to design to let your hi-fi gear breathe in the open air and have tea with the rest of the family.

To answer the question, there are two main considerations.

Structural integrity and heat dissipation.

Structural integrity can be determined the old fashioned way, just heft any component in your hands to get an idea if you can get away with laying anything on top. Even just a few components can add up to 50+ pounds. Consult the owners manual to see if they have any explicit instructions as to how much capacity if any that it can take. But even if nothing is read in the manual about it, common sense can go a long way. A plastic $30 DVD player from Wall Mart isn't the best choice to anchor your system at the bottom.

Heat dissipation is trickier. If you look at the box you can usually determine where the manufacturer intended heat to dissipate from. Vents should be given the opportunity to do their job, so give them plenty of space. Components usually have legs that raise them from the component below, this is a great design but too often won’t leave enough space or sit too flat on top of the one below. Spacers (possibly wooden chims) to space component tops from the one bottom of the one above it can help in these cases. Some components have vents on the back, so it's important not to crowd the back in either, give some space from behind. If you’re crowding everything into a closed entertainment center, it might be a good idea to invest one or more small fans you switch on for long viewing periods.

Components with moving parts like today’s PVRs including RePlayTV, TiVo or your satellite/cable receiver PVR have built in hard drives that generate a lot of heat. If your DVR is also an HD receiver, it’ll have processors also creating veritable micro-furnace inside. A PVR that runs hot all its life will probably have a shortened life expectancy and have more errors. The thin film magnetic media that makes up the hard drive platter can be susceptible heat damaged. Bad sectors could mean odd intermittent behaviors like stuttering, sound or image cut outs.

Amplifiers and receivers are components that have amplifiers built in which are VERY temperature sensitive. It's paramount that you not place anything on top of a receiver. Amps radiate a lot of heat, keep the top of your amps as clear as possible and if it’s enclosed with scant clearance on top, that's the best place to have a small fan.

I often wish they made small clip on fans that run on AC. I'd buy about three of them for my system. The clip is nothing special, just to clip it to the edge of a shelf.

As a general rule I’d say about an inch between components for heat dissipation is good, depending on the components. Obviously receivers require more than an inch

If you’re particularly concerned that a component is heating up too much and not being given enough breathing space test it with your hand after it’s been running awhile. If it feels hot to the touch on the top of the box, it’s probably too hot inside and this could be damaging to semiconductor material and drying out lubricants on any moving parts. If you have components that don’t pass the hand test you should get a fan in there ASAP. Light air current passing over a few of your components will make a huge difference.