Entertainment Centers: Destroyer of Good Sound Systems

There is a class of furniture that we all know which has a variety of names and can be found in most homes today in developed nations across the globe. The function of this furniture is mainly to hold and store entertainment electronics such as televisions, receivers, gaming consoles, and so on. In their simpler, benign incarnation, they are just a TV shelf stand and do not take up a lot of space nor are they of elaborate construction. However, in their malignant form, they are ‘entertainment centers,’ extravagant monstrosities that devour innocent audio/video systems and spit them out as a pale shadow of what could have been a nice entertainment system. Let’s talk about how entertainment centers destroy good audio and video presentation and should be repudiated by civilization as a whole.

But before we get into the problems of entertainment centers, we have to address why people want them in the first place. Entertainment centers are basically elaborate shelves that not only store things but display things. A lot of people place pictures, figurines, crafts, or small artworks to display in the open cabinets of entertainment centers. It’s not unreasonable to want a place to display family photos or nice looking art pieces. Furthermore, all of the different shelving slots are an appealing way to organize things for those among us who are manic about organized storage. I can sympathize with this perspective since I do like having specific locations for things so I don’t have to think about where I left some object that doesn’t have a designated location for storage. I like to keep track of stuff. And, of course, as was mentioned, entertainment centers are a place people can place televisions and other entertainment electronics.

The problem arises due to a conflict with how audio and video electronics are best able to do their job within a large and heavily compartmentalized shelving system. Basically, audio and video electronics like spacious areas for the best performance and operation, but entertainment centers are typically very restrictive of allocated space for those types of components. Let’s now discuss some of the ways in which the rigid and constricting compartments of entertainment centers are killing your home audio/video system.

Diffraction effects of placing speakers in confined locations

Placing loudspeakers into cubbyholes or enclosed cabinet spaces creates a detrimental acoustic effect called diffraction. Acoustic diffraction is interference that occurs when sound from a reflection collides with the direct sound from the point of acoustic emission. To explain it in simpler terms, loudspeakers don’t just emit sound in a single direction; much of the sound that they produce is often projected at a very wide angle. The wider-angle acoustic emissions will bounce off any nearby surfaces and objects, and these reflected sounds can also reach the listener, but since they take an indirect path to the listener, they are slightly delayed relative to the sound that comes straight from the loudspeaker. That slight delay causes conflicts in the frequency response because the peaks and troughs in the soundwaves from the direct and reflected sound are misaligned. This can cause a phasey sound which can degrade the soundstage and can hurt clarity in midrange and lower treble frequencies. We also discussed this effect in our article on loudspeaker grilles.

Diffraction is one of the reasons why loudspeakers perform best when placed away from nearby surfaces. However, that is just about the opposite of what happens when they are placed in a cubbyhole or cabinet shelf, which is what an entertainment center usually provides. Entertainment centers are normally lousy places to place a loudspeaker yet is so often where they end up in so many people’s homes. If you have speakers placed in any kind of shelving or desk space, one thing you can do to help reduce diffraction effects is to pull the speaker up flush with the edge of the shelf so that there is no shelf surface in front of the speaker. But the best thing to do is put the speaker on a stand in the room away from nearby surfaces.

Boundary gain from placing speakers in confined locations

As we mentioned above, most speakers emit sound at a very wide angle (to see how wide, just look at any of our speaker reviews where we measure the width of the loudspeakers dispersion angle). This is especially true for lower frequencies where most speakers behave as an omnidirectional radiator (meaning they emit sound in all directions nearly equally). In other words, loudspeaker bass goes everywhere and doesn’t have a preferred direction. You can strengthen bass output by restricting the space that it can pressurize since all of that acoustic energy becomes confined to a smaller area. For example, take a speaker from out in the middle of a room and then place it against a wall, and listen for the difference in the bass response. It will be significantly increased since you halved the space where the acoustic energy can move in. You can further increase the bass output by moving the speaker into a room corner, which again halves the space that the sound can project outward as compared to against a wall. This effect is called boundary gain; the more boundaries that you place around an energy-emitting source, the greater the energy will load in the remaining space.

Now think about how the bass can be loaded by placing a loudspeaker into a cubbyhole such as is provided by entertainment centers; it will get a very substantial boost, usually way too much. It can make the sound system sound muddy and boomy. It also greatly degrades dialogue intelligibility. If you sometimes have trouble understanding dialogue from your sound system, and the speakers are located in congested areas, the boundary gain could be simply boosting the bass too much. You might be thinking that a little extra bass is fun, but the problem is that the excess bass that many people can sometimes enjoy really only occurs in deep bass, as in below 100 Hz. However, the bass boost that comes from boundary gain can extend way above that frequency, well into upper bass frequencies like out to 500Hz. Few people would find excess upper bass pleasant, indeed on the occasions that I have run into it, I have found it to be obnoxious. Nonetheless, it is a common problem that results from placing speakers in entertainment centers.

Editorial Note About Placing Speakers Inside Entertainment Centers: If you absolutely must place speakers inside of entertainment center cubby holes, lining the interior of the holes with thick insulation or absorptive material to eliminate any air gap between the speaker and its surrounding space will help minimize diffraction and reduce boundary gain. It is further advised to bass manage your speakers and/or plug the rear ports (if any).

Restrictions on the size of center speakers

Two-way center speakers carry inevitable compromises that we at Audioholics have often written about in the past (A few articles: Vertical vs Horizontal Center Speaker Designs, Alternate Perspective, Center Speaker Additional Considerations). While a two-way center speaker turned on it's side (Ie. MTM) can make for a fine center-speaker design, it could never make for a great one due to problems inherent in the design. To be blunt, the best center speakers are three-way designs. The problem is that three-way center designs are usually taller than two-way center designs since three-way centers usually mount the midrange driver on a vertical plane with respect to the tweeter. That prohibits the use of many three-way designs in the vertically narrow shelf space of many entertainment centers. Even worse are the entertainment shelves with such low clearance that they force the use of center speakers with small diameter woofers, so they can not even fit a center speaker with 5” woofers let alone a three-way center.

This is a big problem because the center speaker is the most important speaker in a surround sound system. It is where most dialogue in sound mixes come through. It is the most heavily-used speaker in modern sound mixes and thus the speaker subject to the greatest dynamic range in content. It is the speaker that you least want to compromise, yet is so often compromised simply because the shelf space doesn’t have enough vertical clearance. Again, having problems with dialogue intelligibility? It could possibly be due in part to the design of the center speaker itself- especially ones made to fit in short spaces because they will have smaller woofers. The problem with two-way horizontal centers with small woofers is that those speakers likely have a higher crossover frequency to the tweeter which gives the woofers a wider frequency range in which to create destructive off-axis lobing. Entertainment centers can often force users to use a weak center speaker.

One more point worth mentioning here is that a lot of entertainment centers don’t have any dedicated shelf at all for center speakers since the shelving arrangement divides the entertainment center in half. I suppose you could place the center speaker off to the side in a system like that, but that just about defeats the purpose of a center channel to begin with.  

Poor ventilation for electronics

Many modern entertainment electronics can generate a not-insignificant amount of heat. Amplifiers sometimes have to pump out hundreds of watts to loudspeakers. Gaming consoles have extremely fast and power-hungry processors onboard. Pre-amps, power conditioners, and source components such as HTPCs all put out heat as well. These electronics are all designed to disperse heat away from the units themselves as heat is one of the leading, if not the leading, cause of premature electronics failure. The problem is, if these components are placed in a location with poor ventilation. There is nowhere the heat can go, so it just builds up. So how many entertainment centers do you know of which give a lot of space around electronics with open airflow through the back of the cabinet?

Modern electronics function best where there is airflow around them. An enclosed cubby, especially one with low clearance, is a location where heat isn’t efficiently circulated away from the device. If you want better long-term reliability from your electronics, do not operate them in the kind of congested cabinets that entertainment centers normally provide. If you absolutely have no choice, then open the back, and add a cooling fan.

Poor rear access for cabling

The tight cabinet spaces in many entertainment centers aren’t just a plague to audio and video device functions, it is also a substantial inconvenience on any occasion where you need to hook up any electronics. Most entertainment centers do not have open back cabinets, but they do have notches and holes where you can thread cabling. As anyone knows who has tried to thread wires across multiple shelves through these types of systems, it can be a pain in the neck. Think about the hassle of installing an AVR in a typical entertainment center: threading a power cable to a hidden power strip or power conditioner, threading speaker cable to the left, right, center, and subwoofer (god help you if you want to route wire to surrounds), and threading all of the signal cables in from every device as well as out to the television. Every time you want to replace or add a device, entertainment centers make a major chore out of replacing or adding anything electronic. Simple TV shelves that can easily be pushed away from the wall do not come with this headache.

Restrictions on television sizes

Big televisions are insanely cheap these days. I remember a few decades ago when a 32” TV was considered quite large and expensive. Nowadays, a 32” TV is considered small and cheap and usually reserved for a PC desktop monitor application. You can get a 75” 4K TV for less than $1k on a deal. Where a nice 85” TV can be had for under $3k, it makes increasingly less sense to go through the complexity of installing a projection system unless you really want a huge display. With UHD resolution and HDR brightness and contrast levels, you can have gigantic screen sizes yet still have a crystal clear image. Everyone loves a large image for a larger-than-life cinematic experience. Yet many entertainment centers only have a relatively small television enclosure which forces users into getting maybe a 55” screen if they are lucky, thereby missing out on the modern marvel of enormous screen sizes for such low prices.

There are other disadvantages of entertainment centers that are worth mentioning but do not make the above list since they don’t adversely affect the function of audio/video equipment directly. Among these disadvantages is the cost of entertainment centers; they tend to be quite expensive. Simple TV stand type cabinets are far less expensive and way less deleterious to audio/video performance than large entertainment center systems. Another drawback of entertainment centers is that they take up an awful lot of floor space. A big one will shrink the size of your room and make it less spacious than it might be otherwise. And another downside of entertainment centers is a personal criticism from myself, but I think they don’t tend to look great. Many of them are domineering as pieces of furniture. They can be a gigantic shelving system that eats up an entire wall and looks very busy from all of the elaborate shelving. Some of the more expensive ones can be over-decorated to the point of being baroque. They would be a better aesthetic fit in a seventeenth-century French palace than a modern home.

OK, so we know why you don’t like entertainment centers. What do you suggest instead?

Let’s now talk about what I would recommend in place of an entertainment center. For the purposes of better audio and video, I would suggest a low-profile, minimalist TV stand. The reasons are many:

• If you want to place bookshelf speakers on a simple TV stand, they won’t be boxed in by cabinetry, thereby lessening diffraction effects and boundary gain.
• There is plenty of room for a center speaker is placed on top of the stand. This, of course, works better where the TV is wall-mounted.
• A lower-profile TV stand allows a lower placement of the TV for a more optimal viewing angle for comfortable long-term viewing.
• A TV stand with an open back will offer better ventilation for electronics, especially if it is not placed right against the wall.
• TV stands are easier to work around to access rear panels of electronics and cabling. The only caveat is that cabling will be more exposed, so those who want a clean look will have to do a bit more work for tidy cable management.
• A good functional TV stand doesn’t need to cost a fortune nor does it have to eat up a lot of space.
• A TV stand is a more sightly piece of furniture than an entertainment center, so it will not dominate the room’s interior decor.

Conclusion

To be fair, not all entertainment centers are the overbuilt abominations described by much of the above criticisms. Some are a bit more austere in design than others, and that is a good thing. If you want an entertainment system that doesn’t interfere with audio and video performance so much, a good rule of thumb is “less is more.” The less stuff you have around A/V components, the better it is for the components. If you have stuff you want to store or display on the same wall as your audio/video system, a good alternative is floating shelves mounted away from the loudspeakers and television. It is probably too much to hope for to see a decline in popularity of these massive entertainment centers, however, we do hope that individual readers will now be better informed about the problems inherent in these abhorrent furniture designs and know to steer clear from them.