Phase Technology dARTS DCB-1.0-LR Frequently Asked Questions Manual

PRESENTS

dARTS

DIGITAL AUDIO REFERENCE THEATER SYSTEM

ENTERTAINMENT WITHOUT BOUNDARIES

© 2007

WHAT IS THE PROBLEM?

For many hundreds of years, even back to the days of Bach, engineers, architects and performers have known that the most

important contributing factors to the sound of music or theater in a room have been the acoustic properties of the room

itself. Each dimension of a room (height, width, depth) creates room modes at many different frequencies that interact with

the room in very different ways, depending on where one is sitting or standing. Thus, every room contributes its own sonic

signature to the music by altering the content at all frequencies as they are played. Room acoustics also affect sound

reproduction by the amount of reflection and absorption they cause at various points within the room.

Loudspeakers interact with their environment − just as an orchestra does − and play a major role in how much we enjoy our

entertainment at home. Our homes are typically not designed to be marvels of acoustic engineering, like a fine concert hall.

Speakers are frequently placed wherever they happen to fit into the décor, without any thought given to how that

placement will react sonically with the room. The room’s many modes come into play. Standing waves and dips wreak

havoc with uniform bass response throughout the listening area, and walls and furnishings create major reflections and

absorptions to destroy the focus, clarity and detail of the sound. Because few of us have dedicated, purpose-built listening

rooms, the needs of daily life in our homes usually dictate that “state of the decor beats state of the art.”

It is well known that the speaker is the weakest link in any entertainment system. Modern amplifiers, preamps and source

components have reduced their distortion levels to a vanishingly low point and can be made to operate in a very linear

fashion. Speakers, however, are still a combination of imprecise mechanical parts and passive electrical components that

contribute significant distortion to the audio signal.

Speaker drivers − woofers, midranges and tweeters − react to the input signal, moving at many different speeds to

reproduce the entire audible spectrum. Each individual driver has an incredibly difficult job to do, and even the very best

raw speaker drivers won’t necessarily work well together. When we try to match them to each other to create a full-range

speaker system, it’s amazing that they work as well as they do. Production tolerances are difficult to maintain between

drivers, causing a lack of consistency in production of speakers. It’s rare to see drivers within an individual speaker matched

to within +/- 2 dB, much less between two or more finished speakers. Couple that with the many ways a speaker interacts

with the room environment, based on how it’s placed, and it becomes a seemingly impossible task to create really lifelike

sound reproduction. It is all a matter of optimizing compromises, and since the speaker’s designer has no idea how the

speaker will be used, there is no way to assure any sort of predictable response from a passive speaker system in a room.

The crossover network has the task of separating the various frequency bands and sending them to the appropriate

speaker driver, hopefully within each driver’s linear range of operation. The crossover also tells each driver how to move in

relation to each other, which is particularly critical in the regions where the crossover point between drivers overlaps. The

electronic components in the crossover network change their electrical characteristics as they warm up and cool down, they

change as they try to deal with loud signals which can saturate them, and they react differently as the drivers present a

constantly changing impedance load based on frequency. Even using components with very close tolerances does not mean

that they will react the same way to both heat and widely varying signal levels. Thus, a speaker system’s crossover first

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takes apart the input signal electronically, and then the speaker’s drivers need to put it back together mechanically and

acoustically, including the interface with the room itself.

Now, let’s suppose you’ve found speakers you really like. You take them home and hook them up, but there’s still no

guarantee they’ll sound good in your room.

• Are the vertical and horizontal dispersion characteristics of the speakers appropriate to your equipment location

and the room’s seating?

• Can you get a good enveloping soundfield at more than one or two seating positions?

• Does the sound change as you stand up or sit down or move from side to side?

• Are the speakers placed so that the sound from each arrives at your ears at exactly the same instant?

• Do the room’s furnishings and surfaces impact each speaker’s output the same way?

• Are all of your speakers voiced to sound absolutely identical (necessary to provide seamless blending of both the

front soundstage and the surround soundfield)?

• Are your speakers properly matched to your amplifier so they can provide proper damping to control the motion

of the drivers?

• Does your amplifier have sufficient power to produce undistorted peaks in all of your speakers, regardless of the

program material?

• Do your speakers have sufficient power handling to safely utilize that amplifier’s power on sudden peaks?

• Will the speakers handle that power without subtly overloading and compressing the peaks, yielding unrealistic

sound?

• How will your subwoofer react with the room’s acoustics if you can’t place it where physics dictates is the “proper”

location?

• How will your subwoofer blend with your other speakers?

These are just some of the questions that need to be answered to produce a realistic representation of music or movies in

the home or studio. It sounds pretty daunting, doesn’t it?

WHAT IS THE SOLUTION?

If we can’t just buy excellent products and install them into a room, expecting good results, what can be done? The

professional audio world has known for years that a big part of the solution is to use active speakers, meaning that the

speakers are coupled with amplifiers designed and equalized to complement the response of the speakers. This results in a

synergistic whole much greater than the sum of unknown parts. Professional recording studios, theaters and concert halls

have long done sophisticated measuring and modeling of the room’s acoustic properties and dimensions and have then

spent many tens or even hundreds of thousands of dollars adding treatments to precisely control reflections, reverberation

and bass energy. How often can we do that in our homes? How often does even a dedicated media room include all of the

treatments needed to remedy its inherent acoustic properties? Even if it is treated, which can still cost tens of thousands of

dollars, we know speakers and amplifiers vary widely in their responses to the constantly changing program material.

What can be done to assure hearing every detail in every soundtrack and musical recording just as the artists intended?

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