Why use Dipolar speakers for rears?
 Like movie theater surround speakers, reverberant surround/ rear speakers envelop you in sound without drawing your attention away from the movie you’re watching. They add size and dimension to the soundstage and ensure a seamless transition when sounds and effects move from the front and center to side and rear speakers.
Movie theaters use multiple arrays of surround/rear speakers to keep viewers from being distracted by the sound of any single one.
Conventional forward-radiating speakers cannot reproduce movie theater surround sound in your home. If they are loud enough for their sound to blend with the front speakers they draw attention to themselves. Turn them down so they don’t distract you and they won’t blend with the fronts.
So how can you hear all of the glorious surround sound you’re supposed to? With reverberant soundfield surround/rear speakers placed to the sides and rear of the listener.
Like movie theater surround speakers, reverberant surround/rear speakers envelop you in sound without drawing your attention away from the movie you’re watching. They add size and dimension to the soundstage and ensure a seamless transition when sound and effects move from the front and center to side and rear speakers.
They’re just as important for multichannel music. Because of their ability to create a large non-localized soundfield, they contribute multidimensional realism to the reproduction of the original recording’s acoustic space.
The diffuse sound of reverberant surround/rear speakers turns your listening into a magical experience—they put the “theater” in home theater and make music sound “live”!
How to evaluate speakers?
 When evaluating speakers don't let what you see influence what you hear. For example:
• Speaker Size:
Is bigger better than smaller, or smaller better than bigger?
•Driver Size:
Are bigger drive units better than smaller ones?
•Design Type:
Which design type is better–bass reflex (ported) or acoustic-suspension (sealed)? Dynamic drivers or panels?
• Price:
Are exorbitantly priced speakers better than more affordable ones?
None of these factors is necessarily related to sound quality. When it comes to speakers, what counts most is how they sound!
How to compare speakers?
 Here are some tips to help you evaluate speakers.
Make side-by-side comparisons.
Our acoustic memory is short. It’s hard to remember Speaker "A" if you have to go to a
different room to compare it to Speaker "B".
Listen to speakers at equal volume.
Even small variations in loudness can easily be mistaken for differences in sound quality.
Turn the video off.
Eliminating visual distraction will help you focus on the sound, even in a home-theater demonstration.
Listen for clarity.
Are the speakers clear, natural-sounding and intelligible with instruments and voice?
Listen for a "seamless" soundstage.
The speakers should present a broad, cohesive image of the original sound.
Listen to the bass.
Is it deep, tight and well-defined?
Sit up straight, then slouch.
If you hear distinct changes in sound quality, the speakers may have a deficiency in their vertical dispersion.
Move around.
Good speakers disperse sound over a wide listening area. Move around to find out what others in different listening positions will hear.
Following these tips will help you control the variables and compare "apples to apples". Take your time and trust your ears. Hearing is Believing!
What is Distortion?
Coloration is caused by physical resonances in a speaker or its enclosure, its frequency response imbalance, directivity and harmonic distortion. Distortion is the creation of additional sounds resulting from unwanted tones or noise caused by the speaker's mechanical or electrical operation.
Two kinds of distortion are most common. The first, Harmonic distortion is heard as additional tones which are simple multiples of the original note played. If a speaker is supposed to reproduce a 40-Hz note, for example, it may also produce output at 80 Hz, 120 Hz, 160 Hz and so on, even though these tones are not part of the original sound.
The second kind, Non-harmonic distortion does not have a simple mathematical relationship with the original note–we typically hear this as a buzz, rattle or other “mechanical” noise.
What is Colouration?
Every material resonates when struck or activated. This is how different materials, or for that matter musical instruments, make their identifiable sounds or tones. Speakers should be neutral, having no identifiable sound of their own, but speakers are prone to resonances that color or alter the sound–these are unwanted and must be eliminated. In the same way the tint in a pair of sunglasses colors what you see, unwanted resonances color what you hear. They impose themselves on vocals and instrumental sounds being reproduced ( see chart). Coloration compromises fidelity and hampers imaging by blending sounds together. Speakers with low colouration are timbrally accurate–they faithfully represent the timbre or distinctive character of every sound it reproduce.
Common colourations that must be controlled to ensure greater reproduction accuracy:
Shrill or Dull.
Overall sound is too sharp (shrill) or too muffled (dull).
Harsh.
Resonances in the 2 kHz to 8 kHz region make high frequencies sound grating.
Nasal.
Speak while pinching your nose. Resonance problems in the 1 kHz to 2 kHz range result in a
“nasal-like” sound.
"Ahh" Sounding.
Cup your hands and place them around your mouth. Say “ahh” and listen for this characteristic.
It is caused by problems with resonances in the 600 Hz to 1 kHz range.
Hollow.
Form a cylinder with one hand. Place it to your mouth and speak. A speaker that sounds like this
has resonance problems in the 200 Hz to 600 Hz range.
"Boxy"
These speakers are plagued by uncontrolled enclosure resonances in the 90 Hz to 200 Hz region.
Upper bass lacks clarity and definition.
"Boomy"
In a “boomy” speaker, sound in the 60 Hz to 100 Hz range is overblown. Bass is “bloated”
and poorly defined.
Dispersion?
The fundamentals of natural sound travel uniformly in all directions – a piano, for example, distributes sound throughout a room.
Our hearing favors speakers that reproduce sound in the same way. Wide-dispersion speakers sound more real because they too fill the room. Limited-dispersion speakers seem less realistic because they beam, or project sound into only one area.
Wide dispersion throughout a speaker’s bandwidth is difficult to achieve. Most high-frequency and bass/midrange drive units have good dispersion at the lower limits of their frequency range, but they naturally start to beam as they reach their upper-frequency limits. With high-performance high-frequency drivers beaming occurs beyond audibility. Beaming from midrange drivers, however, occurs within the audible range. Speakers with beaming problems will not sound the same in all areas of a room. They may sound balanced in one area, but nasal, dull, or even harsh and shrill in other areas.
Midrange beaming can be reduced by lowering the crossover frequency. The high-frequency driver’s lower range will then provide wider dispersion and the bass/midrange driver’s output can be rolled off before its dispersion narrows.
This is an effective approach but requires the use of a high-frequency drivers that can handle the vast amounts of power it takes to reproduce these frequencies. This driver must be very robust and as a consequence, will be expensive to produce. Many speaker companies are unwilling to incur the cost of building high-power high-frequency drivers, thus not all speakers have uniformly wide dispersion.
Drivers that pivot in custom speakers are better?
 Some would have you believe that in-wall/in-ceiling speakers require drivers that pivot. This is not standard practice in high-performance bookshelf or floorstanding speaker design, and for the same reasons it is counterproductive for in-wall/in-ceiling speakers.
Typical in-wall/in-ceiling speakers use inexpensive low-performance drivers. They may even be dressed up with impressive looking cones or domes to make you think they are engineered designs, but nothing could be further from truth. These speakers not only have poor sound, they also have poor dispersion resulting in sonic hot spots — too much sound in one part of the room and not enough in another.
Pivoting the woofer and tweeter is no better. Pivoting the woofer and tweeter in different directions will result in listeners hearing drastically different frequency responses—it’s impossible to have accurate sound with these drivers aimed in different directions. Pivoting the woofer and tweeter in the same direction doesn’t solve the problem either. Since these systems beam sound to sonic hot spots (like a spotlight), pivoting the woofer and tweeter in tandem will simply move the sonic hot spot to another area of the room.
Pivoting tweeters don’t address the problem (they generally have wider dispersion already). The problem of poor dispersion is in the midrange-tweeter interface. To accommodate the pivoting mechanism a small low-power plastic encapsulated tweeter is required, which necessitates a higher crossover to prevent thermal failure. Upper midrange must then be reproduced by the woofer, which becomes directional (beams) in that region. Pivoting the tweeter will aim high-frequency sound toward listeners, but the all-important midrange will not reach them. The result is a progressively “ sucked-out” midrange and bright, screechy high frequencies.
Paradigm® in-wall/in-ceiling speakers use superior high-performance, high-power drivers. Where applicable we even use heatsinks on our high-frequency drivers for higher power handling. This allows us to use lower crossover points and ensure wide dispersion. Sonic hotspots are eliminated— every listener hears superb imaging at volume levels that are equal throughout the room. Because we have addressed the root of the problem—wide dispersion through the upper midrange—pivoting drivers are simply not required.
Buyer Beware!
When you’re ready to purchase, remember, you're also buying many hours of listening enjoyment, Keep these things in mind:
Check Them Out
Investigating the reputation of the brand name. Is it established and nationally advertised? What do reviewers say about the speakers?
Great Deals That Aren’t
Discounts can be deceptive, especially if the speakers you’re looking at have an inflated list price. Never buy poor-sounding speakers just because of a discount.
Be Skeptical of "Design Breakthroughs"
All too often the latest ?design breakthrough? is simply an old idea with a new name.
Buy Only From A Specialty Retailer
Only specialty retailers have the expertise and resources to properly demonstrate high-performance speakers – and to assemble a system that will save you time, frustration and money.
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