Loudspeakers (part 1)

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Of all the components in your audio system, the loudspeaker’s job is by far the most difficult. The loudspeaker is expected to reproduce the sound of a pipe organ, the human voice, and a violin through the same electromechanical device—all at the same levels of believability, and all at the same time. The tonal range and complex harmonic structure of virtually every instrument in the orchestra is to be reproduced from a relatively tiny box. Loudspeakers that are part of a home-theater system are also expected to reproduce car crashes, tornadoes, and explosions—some times simultaneously with dialogue.

It’s no wonder that loudspeaker designers spend their lives battling the laws of physics to produce musical and practical loudspeakers. Unlike other high-end designers who create a variety of products, the loudspeaker designer is singular in focus, dedicated in intent, and deeply committed to the unique blend of science and art that is loud speaker design.

Although even the best loudspeakers can’t convince us that we’re hearing live music, they nonetheless are miraculous in what they can do. Think about this: A pair of loudspeakers converts two two-dimensional electrical signals into a three-dimensional “soundspace” spread out before the listener. Instruments seem to exist as objects in space; we hear the violin here, the brass over there, and the percussion behind the other instruments. A vocalist appears as a palpable, tangible image exactly between the two loudspeakers. The front of the listening room seems to disappear, replaced by the music. It’s so easy to close your eyes and be transported into the musical event.

To achieve this experience in your home, however, you must carefully choose the best loudspeakers from among the literally thousands of models on the market. As we’ll see, choosing loudspeakers is a challenging job.

How to Choose a Loudspeaker

The world abounds in poor-quality, even dreadful, loudspeakers. What’s more, some very bad loudspeakers are expensive, while superlative models may sell for a fraction of an inferior model’s price. There is sometimes little relationship between price and musical performance.

This situation offers the loudspeaker shopper both promise and peril. The promise is of finding an excellent loudspeaker for a reasonable price. The peril is of sorting through mediocre models to find the rare gems that offer either high absolute performance, or sound quality far above what their price would indicate.

This is where reviews come in handy. Reviewers who write for audio magazines hear lots of loudspeakers (at dealers, trade shows, and consumer shows), but review only those that sound promising. This weeds out the vast majority of under achievers. Of the loudspeakers that are reviewed, some are found to he unacceptably flawed, others are good for the money, while a select few are star overachievers that clearly outperform their similarly priced rivals.

The place to start loudspeaker shopping, therefore, is in the pages of a reputable magazine with high standards for what constitutes good loudspeaker performance. Be wary of magazines that end every review with a “competent for the money” recommendation. Not all loudspeakers are good; therefore, not all reviews should be positive. The tone of the reviews—positive or negative—should reflect the wide variation in performance and value found in the marketplace.

After you’ve read lots of loudspeaker reviews, make up your short list of products to audition from the crème de la crème. There are several criteria to apply in making this short list to ensure that you get the best loudspeaker for your individual needs. As you apply each criterion described, the list of candidate loudspeakers will get shorter and shorter, thus easing your decision-making process. If you find yourself with too few choices at the end of the process, go back and revise your criteria. For example, if you find a loudspeaker that’s perfect in all ways but size, you may want to find the extra space in your living room. Similarly, an ideal loudspeaker costing a little more than you planned to spend may suggest a budget revision. As you go through this selection process, remember that the perfect loudspeaker for you is probably out there. Be selective and have high standards. You’ll be rewarded by a much higher level of musical performance than you thought you could afford.

Your first decision in choosing loudspeakers is whether your system will reproduce 2-channel music, multichannel music, film soundtracks as part of a home- theater system, or all of these. No matter what loudspeaker configuration you choose, the three starting criteria for making your short list of candidates will be the same. Let’s look at those criteria:

1) Size, Appearance, and Integration in the Home

After you’ve designated a place for your loudspeakers, determine the optimum loud speaker size for your room—the urban apartment dweller will likely have tighter size constraints than the suburban audiophile. Some listeners will want the loudspeakers to discreetly blend into the room; others will make the hi-fi system the room’s center of activity and won’t mind large, imposing loudspeakers. When choosing a place for your loudspeakers, keep in mind that their placement is a crucial factor in how your system will sound. (Section 12 includes an in-depth treatment of loudspeaker positioning.)

The loudspeaker’s appearance is also a factor to consider. An inexpensive, vinyl-covered box would be out of place in an elegantly furnished home. Many high- end loudspeakers are finished in beautiful cabinetry that will complement any decor. This level of finish can, however, add greatly to the loudspeaker’s price.

If you don’t have room for full-range, floorstanding speakers, consider a separate subwoofer/satellite system. This is a loudspeaker system that puts the bass-reproducing driver in an enclosure you can put nearly anywhere, and the midrange- and treble-reproducing elements in a small, unobtrusive cabinet. You’ll still get a full sound, but without the visual domination of your living room that often goes with floor-standing speakers. Moreover, the satellite speakers’ small cabinets often help them achieve great soundstaging. An added benefit is that you can position the woofer cabinet for best bass performance and the satellites for best soundstaging.

If your room won’t easily accommodate floorstanding or stand-mounted loudspeakers, consider on-wall or in-wall models. As its name suggests, the in-wall is mounted inside a cavity cut into drywall ( FIG. 1). The on-wall is generally a very shallow, slender speaker that mounts to the wall ( FIG. 2). The popularity of flat-panel television (LCD and plasma) has fueled the growth of on-wall models that complement a flat-panel video display. Although in-wall and on-wall loudspeakers have improved dramatically in the past few years, they will not deliver the same sound quality as a good free-standing loudspeaker.

FIG. 1 In-wall loudspeakers can be mounted unobtrusively.

2) Match the Loudspeaker to Your Electronics

The loudspeaker should be matched to the rest of your system, both electrically and musically. A loudspeaker that may work well in one system may not be ideal for another system—or another listener.

Let’s start with the loudspeaker’s electrical characteristics. The power amplifier and loudspeaker should be thought of as an interactive combination; the power amplifier will behave differently when driving different loudspeakers. Consequently, the loudspeaker should be chosen for the amplifier that will drive it.

The first electrical consideration is a loudspeaker’s sensitivity—how much sound it will produce for a given amount of amplifier power. Loudspeakers are rated for sensitivity by measuring their sound-pressure level (SPL) from one meter away while they are being fed one watt (1W) of power. For example, a sensitivity specification of “88dB, 1W/1m” indicates that this particular loudspeaker will produce a sound-pressure level of 88dB when driven with an input power of 1W, measured at a distance of 1m.

FIG. 2 On-wall loudspeakers create a sleek, low-profile look.

As we saw in the previous section, a loudspeaker’s sensitivity is a significant factor in determining how well it will work with a given power-amplifier output wattage. To produce a loud sound (100dB), a loudspeaker rated at 80dB sensitivity would require 100W. A loudspeaker with a sensitivity of 95dB would require only 3W to produce the same sound-pressure level. Each 3dB decrease in sensitivity requires double the amplifier power to produce the same SPL. (This is discussed in greater technical detail in Section 8, “Power and Integrated Amplifiers.”)

Another electrical factor to consider is the loudspeaker’s load impedance. This is the electrical resistance the power amp meets when driving the loudspeaker. The lower the loudspeaker’s impedance, the more demand is placed on the power amp. If you choose low-impedance loudspeakers, be certain the power amp will drive them adequately. Keep in mind that a speaker rated at “8 ohms” will probably not present an 8-ohm load to the amplifier at all frequencies. Nearly all loudspeakers have dips in the impedance at certain frequencies, making them harder to drive.

On a musical level, you should select a loudspeaker as sonically neutral as possible. If you have a bright-sounding CD player or power amp, it’s a mistake to buy a loudspeaker that sounds soft or dull in the treble to compensate. Instead, change your CD player or amplifier.

Another mistake is to drive high-quality loudspeakers with poor amplification or source components. The high-quality loudspeakers will resolve much more information than lesser loudspeakers—including imperfections in the electronics and source components. All too many audiophiles drive great loudspeakers with mediocre source components and never realize their loudspeakers’ potential. Match the loudspeakers’ quality to that of the rest of your system. (Use the guidelines in Section 3 to set a loudspeaker budget within the context of the cost of your entire system.)

3) Musical Preferences and Listening Habits

If the perfect loudspeaker existed, it would work equally well for chamber music and heavy metal. But because the perfect loudspeaker remains a mythical beast, musical preferences must play a part in choosing a loudspeaker. If you listen mostly to small- scale classical music, choral works, or classical guitar, a minimonitor would probably be your best choice. Conversely, rock listeners need the dynamics, low-frequency extension, and bass power of a large full-range system. Different loudspeakers have strengths and weaknesses in different areas; by matching the loudspeaker to your listening tastes, you’ll get the best performance in the areas that matter most to you.

Other Guidelines in Choosing Loudspeakers

In addition to these specific recommendations, there are some general guidelines you should follow in order to get the most loudspeaker for your money.

First, buy from a specialty audio retailer who can properly demonstrate the loudspeaker, advise you on system matching, and tell you the pros and cons of each candidate. Many high-end audio dealers will let you try the loudspeaker in your home with your own electronics and music before you buy.

Take advantage of the dealer’s knowledge—and reward him with the sale. It’s not only unfair to the dealer to use his or her expensive showroom and knowledgeable salespeople to find out which product to buy, then look for the loudspeaker elsewhere at a lower price; it also prevents you from establishing a mutually beneficial relationship with him or her.

In general, loudspeakers made by companies that make only loudspeakers are better than those from companies who also make a full line of electronics. Loud speaker design may be an afterthought to the electronics manufacturer—something to fill out the line. Conversely, many high-end loudspeaker companies have an almost obsessive dedication to the art of loudspeaker design. Their products’ superior performance often reflects this commitment.

Most of the hundreds of speaker manufacturers buy raw drivers from just a few companies and assemble those drivers into their own cabinets. This makes it relatively easy to start a loudspeaker company. Indeed, the speaker industry is full of small start-ups that create a new design in the hope of joining the ranks of established companies.

At the next level are companies who make high-end loudspeakers in relatively small quantity, but have been in business for some time and have an established dealer base.

Many companies who started at this level have been graduated to the establishment of the high-end. They have moved to relatively large-scale manufacturing yet still maintain high quality These companies are on the threshold between craft-based manufacturing and full-scale industrial manufacturing.

There’s also a class of speaker manufacturer that grew out of its high-end roots to become a mass-market manufacturer. Some of these companies long ago dropped any pretense of being high-end and have instead focused on cutting costs and appealing to the widest possible audience. But some speaker companies founded on high-end principles have retained their dedication to quality despite becoming mass- manufacturers. These companies combine thoughtful and caring design with economy- of-scale manufacturing to deliver products that offer very high performance and extraordinary value. Such companies might not produce state-of-the-art loudspeakers, or even those considered at the upper end of what’s possible in music reproduction, but they consistently deliver superlative sound, solid build quality, and nice cabinetry at reasonable prices. These companies are still driven by a passion for great sound. Such companies are worth your interest.

Don’t buy a loudspeaker based on technical claims. Some products claiming superiority in one aspect of their performance may overlook other, more important aspects. Loudspeaker design requires a balanced approach, not reliance on some new “wonder” technology that may have been invented by the loudspeaker manufacturer’s marketing department. Forget about the technical hype and listen to how the loud speaker reproduces music. You’ll hear whether or not the loudspeaker is any good.

Don’t base your loudspeaker purchases on brand loyalty or longevity. Many well-known and respected names in loudspeaker design of 20 years ago are no longer competitive. Such a company may still produce loudspeakers, but its recent products’ inferior performance only throws into relief the extent of the manufacturer’s decline. The brands the general public thinks represent the state of the art are actually among the worst-sounding loudspeakers available. These companies were either bought by multinational business conglomerates that didn’t care about quality and just wanted to exploit the brand name, or the company has forsaken high performance for mass-market sales. Ironically, the companies with the most visible advertisements in the mass media often offer the lowest-performance loudspeakers.

The general public also believes that the larger the loudspeaker and the more drivers it has, the better it is. Given the same retail price, there is often an inverse relationship between size/driver count and sonic performance. A good two-way loud speaker—one that splits the frequency spectrum into two parts for reproduction by a woofer and a tweeter—with a 6” woofer/midrange and a tweeter in a small cabinet is likely to be vastly better than a similarly priced four-way in a large, floorstanding enclosure. Two high-quality drivers are much better than four mediocre ones. Further, the larger the cabinet, the more difficult and expensive it is to make it free from vibrations that degrade the sound. The four-way speaker’s more extensive crossover will require more parts; the two-way can use just a few higher-quality crossover parts. The large loudspeaker will probably be unlistenable; the small two-way may be superbly musical.

If both of these loudspeakers were shown in a catalog and offered at the same price, however, the large, inferior system would outsell the high-quality two-way by at least 10 times. The perceived value of more hardware for the same money is much higher.

The bottom line: You can’t tell anything about a loudspeaker until you listen to it. In the next section, we’ll examine common problems in loudspeakers and how to choose one that provides the highest level of musical performance.

Finding the Right Loudspeaker—Before You Buy

You’ve done your homework, read reviews, and narrowed down your list of candidate loudspeakers based on the criteria described earlier—you know what you want. Now it’s time to go out and listen. This is a crucial part of shopping for a loudspeaker, and one that should be approached carefully Rather than buying a pair of speakers on your first visit to a dealer, consider this initial audition to be simply the next step. Don’t be in a hurry to buy the first loudspeaker you like. Even if it sounds very good to you, you won’t know how good it is until you’ve auditioned several products.

Audition the loudspeaker with a wide range of familiar recordings of your own choosing. Remember that a dealer’s strategic selection of music can highlight a loud speaker’s best qualities and conceal its weaknesses—after all, his job is to present his products in the best light. Further, auditioning with only audiophile-quality recordings won’t tell you much about how the loudspeaker will perform with the music you’ll be playing at home, most of which was likely not recorded to high audiophile standards. Still, audiophile recordings are excellent for discovering specific performance aspects of a loudspeaker. The music selected for auditioning should therefore be a combination of your favorite music, and diagnostic recordings chosen to reveal different aspects of the loudspeaker’s performance. When listening to your favorite music, forget about specific sonic characteristics and pay attention to how much you’re enjoying the sound. Shift into the analytical mode only when playing the diagnostic recordings. Characterize the sound quality according to the sonic criteria described in Section 4, and later in this section.

Visit the dealer when business is slow so you can spend at least an hour with the loudspeaker. Some loudspeakers are appealing at first, and then lose their luster as their flaws begin to emerge over time. The time to lose patience with the speakers is in the dealer’s showroom, not a week after you’ve bought them. And don’t try to audition more than two sets of loudspeakers in a single dealer visit. If you must choose between three models, select between the first two on one visit, then return to com pare the winner of the first audition with the third contender. You should listen to each candidate as long as you want (within reason) to be sure you’re making the right purchasing decision.

Make sure the loudspeakers are driven by electronics and source components of comparable quality to your components. It’s easy to become infatuated with a delicious sound in a dealer’s showroom, only to be disappointed when you connect the loudspeakers to lesser quality electronics. Ideally, you should drive the loudspeakers under audition with the same level of power amp as you have at home, or as you intend to buy with the loudspeakers.

Of course, the best way to audition loudspeakers is in your own home— you’re under no pressure, you can listen for as long as you like, and you can hear how the loudspeaker performs with your electronics and in your listening room. Home audition removes much of the guesswork from choosing a loudspeaker. But because it’s impractical to take every contender home, and because many dealers will not allow this, save your home auditioning for only those loudspeakers you are seriously considering.

If you are auditioning a multichannel speaker system and the dealer is demonstrating the system with both movies and music, give greater weight to your opinion of the system’s performance with music. It’s fairly easy to impress a listener with the artificial sounds of a movie soundtrack—special effects, explosions, and car crashes. It is much more difficult for a loudspeaker system to reproduce natural sounds such as the human voice, a violin, an acoustic guitar, and other instruments. Moreover, identifying loudspeaker colorations (departures from accuracy) is much easier with recordings of real instruments.

What to Listen For

There are several common flaws in loudspeaker performance that you should listen for. Though some of these flaws are unavoidable in the lower price ranges, a loud speaker exhibiting too many of them should be quickly passed over.

Listen for thick, slow, and tubby bass. One of the most annoying characteristics of poor loudspeakers is colored, peaky, and pitch-less bass. You should hear distinct pitches in bass notes, not a low-frequency, “one-note” growling under the music. Male speaking voice is a good test for upper-bass colorations; it shouldn’t have an excessive or unnatural chesty sound.

Certain bass notes shouldn’t sound louder than others. Listen to solo piano with descending or ascending lines played evenly in the instrument’s left-hand, or lower, registers. Each note should be even in tone and volume, and clearly articulated. If one note sounds different from the others, it’s an indication that the loudspeaker may have a problem at that frequency.

The bottom end should be tight, clean, and “quick.” When it comes to bass, quality is more important than quantity. Poor-quality bass is a constant reminder that the music is being artificially reproduced, making it that much harder to hear only the music and not the loudspeakers. The paradigm of what bass should not sound like is a “boom truck.” Those car stereos are designed for maximum output at a single frequency, not articulate and tuneful bass. Unfortunately, more bass is generally an indicator of worse bass performance in low- to moderately-priced loudspeakers. A lean, tight, and articulate bass is preferable in the long run to the plodding boominess that characterizes inferior loudspeakers.

Listen to kickdrum and bass guitar working together. You should hear the bass drum’s dynamic envelope through the bass guitar. The drum should lock in rhythmically rather than seem to lag slightly behind the bass guitar. A loudspeaker that gets this wrong dilutes rhythmic power, making the rhythm sound sluggish, even slower. But when you listen to a loudspeaker that gets this right, you’ll find your foot tapping and hear a more “upbeat” and involving quality to the music.

Midrange coloration is a particularly annoying problem with some loudspeakers. Fortunately, coloration levels are vastly lower in today’s loudspeakers than they were even 15 years ago. Still, there are lots of colored loudspeakers out there. These can be identified by their “cupped hands” coloration on vocals, a nasal quality, or an emphasis on certain vowel sounds. A problem a little higher in frequency is manifested as a “clangy” piano sound. A good loudspeaker will present vocals as pure, open, and seeming to exist independently of the loudspeakers. Midrange problems will also make the music sound as though it is coming out of boxes rather than existing in space.

Poor treble performance is characterized by grainy or dirty sound to violins, cymbals, and vocal sibilants (s and sh sounds). Cymbals should not splash across the soundstage, sounding like bursts of noise. Instead, the treble should be integrated with the rest of the music and not call attention to itself. The treble shouldn’t sound hard and metallic; instead, cymbals should have some delicacy, texture, and pitch. If you find that a pair of speakers is making you aware of the treble as a separate component of the music, keep looking.

Another thing to listen for in loudspeakers is their ability to play loudly with out congestion. The sounds of some loudspeakers will be fine at low levels, but will congeal and produce a giant roar when pushed to high volumes. Listen to orchestral music with crescendos—the sound should not collapse and coarsen during loud, complex passages.

Finally, the loudspeakers should “disappear” into the soundstage. A good pair of loudspeakers will unfold the music in space before you, giving no clue that the sound is coming from two boxes placed at opposite sides of the room. Singers should be heard as pinpoint, palpable images directly between the loudspeakers (if that’s how they’ve been recorded). The sonic image of an instrument should not “pull” to one side or another when the instrument moves between registers. The music should sound open and transparent, not thick, murky, or opaque. Overall, the less you’re aware of the loudspeakers themselves, the better.

When the speaker is playing loudly, put your hand on the cabinet and feel if it is vibrating. The less vibration, the better. The best loudspeakers will exhibit no apparent cabinet vibration whatsoever.

When auditioning a multichannel loudspeaker package, pay special attention to the center speaker’s performance. The center speaker plays an important role in home theater; specifically, it reproduces nearly all of the film’s dialogue. Listen for how clearly you can hear the actors speaking (called dialogue intelligibility), particularly when the musical score or special effects compete with the dialogue. Select a scene on a DVD that is particularly challenging and play this scene over the loudspeakers you are considering.

Some loudspeakers with less-than-high-end aspirations have colorations intentionally designed into them. The bass is made to be big for “warmth,” the treble excessively bright to give the illusion of “clarity.” Such speakers are usually extremely sensitive, so that they’ll play loudly in comparisons made without level matching. These loudspeakers may impress the unwary in a two-minute demonstration, but will become extremely annoying not long after you’ve brought them home. You unlikely to find such products in a true high-end audio store.

Finally, the surest sign that a loudspeaker will provide long-term musical satisfaction at home is if during the audition, you find yourself greatly enjoying the music and not thinking about loudspeakers at all.

The flaws described here are only the most obvious loudspeaker problems; a full description of what to listen for in reproduced music in general is found in Section 4.

Loudspeakers for Home Theater

Although we’ll cover the role of each loudspeaker in a multichannel audio system in Section 10, a brief overview here will be helpful.

Film soundtracks are mixed into 5.1 audio channels and carried to your home by the Dolby Digital and DTS surround-sound formats. The 5.1 channels are reproduced by five loudspeakers in your living room, plus an optional subwoofer (the “.1” channel). The five loudspeakers are left, center, right, surround left, and surround right. The left and right speakers reproduce most of the film soundtrack’s music and special effects. The center speaker carries the film’s dialogue and some special effects. It also anchors on-screen sounds on the screen. The left, right, and center speakers are together called the front speakers, because they are positioned at the front of your room, with the left and right speakers on either side of your video display and the center speaker mounted on top of or just beneath, the video display. The surround speakers are mounted on the side or rear walls behind the listening position. Their job is to reproduce atmospheric sounds and some special effects. Because surround speakers receive much less signal (and thus amplifier power) than the front speakers, they can be small and unobtrusive.

The subwoofer is optional if you use full-range floorstanding speakers, but a requirement if your five main speakers are small satellites. The subwoofer is usually driven by the “.1” signal in the film soundtrack, a channel reserved for high-impact, low-bass sounds. The subwoofer signal also includes the bass from any channel in which you have designated SMALL in the receiver or controller’s set-up menu. This pre vents low-bass from overloading small speakers.

Loudspeaker Types and How They Work

Many mechanisms for making air move in response to an electrical signal have been tried over the years. Three methods of creating sound work well enough—and are practical enough—to be used in commercially available products. These are the dynamic driver; the ribbon transducer, and the electrostatic panel A loudspeaker using dynamic drivers is often called a box loudspeaker because the drivers are mounted in a box-like enclosure or cabinet. Ribbon and electrostatic loudspeakers are called planar loudspeakers because they’re usually mounted in flat, open panels. The term transducer describes any device that converts energy from one form to another. A loudspeaker is a transducer because it converts electrical energy into sound.

The Dynamic Driver

The most popular loudspeaker technology is without question the dynamic driver. Loudspeakers using dynamic drivers are identifiable by their familiar cones and domes. The dynamic driver’s popularity is due to its many advantages: wide dynamic range, high power handling, high sensitivity, relatively simple design, and ruggedness. Dynamic drivers are also called point-source transducers because the sound is produced from a point in space.

Dynamic loudspeaker systems use a combination of different-sized dynamic drivers. The low frequencies are reproduced by a paper or plastic cone woofer. High frequencies are generated by a tweeter; usually employing a small metal or fabric dome.

Some loudspeakers use a third dynamic driver, the midrange, to reproduce frequencies in the middle of the audio band.

Despite the very different designs of these drivers, they all operate on the same principle ( FIG. 3).

Electrical current from the power amplifier flows through the driver’s voice coil. This current flow sets up a magnetic field around the voice coil that expands and collapses at the same frequency as the audio signal. The voice coil is suspended in a permanent magnetic field generated by magnets in the driver. This permanent magnetic field interacts with the magnetic field generated by current flow through the voice coil, alternately pushing and puffing the voice coil back and forth. Because the voice coil is attached to the driver’s cone, this magnetic interaction pulls the cone back and forth, producing sound. Dynamic drivers are also called moving-coil drivers, for obvious reasons.

Other elements of the dynamic driver include a spider that suspends the voice coil in place as it moves back and forth. The basket is a cast- or stamped-metal structure holding the entire assembly together. (Cast baskets are generally found in higher- quality loudspeakers, stamped baskets in budget models.) A ring of compliant rubber material, called the surround, attaches the cone to the basket rim. The surround allows the cone to move back and forth while still attached to the basket. The maximum distance the cone moves back and forth is called its excursion.

FIG. 3 Dynamic driver cut-away and cross section.

Common cone materials include paper, paper impregnated with a stiffening agent, a form of plastic such as polypropylene, or exotic materials such as Kevlar. Metal (including titanium) has also been used in woofer cones, as have sandwiched layers of different materials. Designers use these materials to prevent a form of distortion called breakup. Breakup occurs when the cone material flexes instead of moving as a perfect piston.

Tweeters work on the same principle, but typically use a 1” dome instead of a large cone. Common dome materials include plastic, woven fiber coated with a rubbery material, titanium, aluminum and aluminum alloys, and gold-plated aluminum. Diamond tweeter diaphragms have also been used in extremely expensive loudspeakers. Unlike cone drivers, which are driven at the cone’s apex, dome diaphragms are driven at the dome’s outer perimeter.

Midrange drivers are smaller versions of the cone woofer. Some, however, use dome diaphragms instead of cones.


Next: Audio for Home Theater and Multichannel Music

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Updated: Wednesday, 2019-07-10 17:10 PST