Frequently Asked
Questions
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What
Can a Professional Custom Installer do for You?
10
Smart Consumer Electronic Tips for the Home Environment
Acoustical Considerations
ACRONYMS
DEFINITIONS
MYTHS AND MISCONCEPTIONS
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What
Can a Professional Custom Installer do for You?
The custom installer can offer:
The sights, sounds and excitement of the movies - in the comfort of your
own home theater.
The pleasures and convenience of high quality audio and video in every
room, controlled from any room.
The safety and peace of mind of a state-of-the-art home security system.
Telephone and intercom communications throughout your home and grounds.
Automated control of lighting, draperies, doors, cabinets, at the touch of
a button.
A professional custom installation makes
it all possible.
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10
Smart Consumer Electronic Tips for the Home Environment
"Who should I talk to about
creating a home theatre?"
"Should I throw away that
VCR?"
If you are bewildered about the consumer
electronics age, Custom Electronic Design and Installation Association
(CEDIA) offers 10 Smart Consumer Electronic Tips for your home
environment.
The 10 Smart Consumer Electronic Tips provide you with a concise and
informative list of helpful hints to assist you in making smart decisions
when purchasing home consumer electronics.
The 10 Smart Consumer Electronics Tips is a collaborative effort developed
by members of CEDIA. Members of CEDIA are knowledgeable and talented
professionals representing all facets of the industry from
designers/installers to manufacturers and sales representatives.
CEDIA developed this list of recommendations after many hours of
collaboration between our members. Our goal for developing this list was
to take an active role in providing assistance to the consumer. These tips
cover four areas: innovation, investments, integration and ease of use.
Although this advice is geared toward the consumer, it is also beneficial
to the custom electronics professional. When building or remodeling, the
designer or builder may use this list as a reference for making
recommendations on home integration to their customer.
Here is the list:
- Wire for everything now – If
you are building or remodeling your home, wire it with a plan for
future needs. While no one can guarantee what the future will look
like, CEDIA Professionals make it their business to stay current to
offer good advice about technologies that are on the horizon. Best of
all they can help you sort out the hype from the reality.
- Plan for HDTV now – High
Definition TV is the new digital standard for enhanced picture quality
for TV broadcasting. If you're buying a new TV or video projector,
make sure you'll be able to enjoy the incredible sound and pictures
that are part of HDTV.
- Insist on integrated systems –
As you buy new electronic components, make sure you shop for equipment
that can be hooked up together and operated with one, easy to use
control system.
- Don’t buy yesterday’s products
(often what is in stock) – Many stores purchase large orders of all
equipment and sell it at discounted rates. Shop with a dealer that
only provides you with new equipment and technologies.
- Consider integrating lighting control
with your home electronics system — Lighting sets the mood for
home theater, entertaining, or just a quiet night at home. You can
control your home lighting from the same remote that you use to
control your theater or music system.
- Think with your wallet, but lead with
your head - Quality and long-term dependability are the most cost
effective attributes that you can build into a home.
- Buy an experience, not a box –
Find a dealer that allows you to test drive the entire system or at
least experience the thrill of a high performance system. Few people
have the time to research and evaluate all the hardware choices. It's
smarter to focus on the end result and make your choices based upon
overall performance and value.
- Don't think you have to put up with
hard to use, multiple remote controls – Easy to use, all-in-one
remote controls are available for any system. You can even have them
custom programmed so they make perfect sense to you.
- Consult a professional -
Designing and installing reliable, easy to use systems that add real
quality to your lifestyle is the goal of CEDIA professionals. Check to
see if the company you're considering has CEDIA Certified Professional
Designers and Installers on staff.
- Increase your service expectations
- Your home electronics system is a big investment. CEDIA
professionals will provide you with extensive options, comprehensive
designs, complete installation and especially, in-home service for
your systems.
Custom Electronic Design and
Installation Association [CEDIA]... professionals ensuring your dollars
are invested well while focusing on the design, integration and
installation.
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Acoustical
Considerations
As audio technology becomes more
sophisticated and more prevalent throughout homes, consumers are becoming
increasingly aware of the need for excellent sound quality and sound
privacy. Manufacturers of audio equipment from compact disc players to
loudspeakers constantly strive to provide their end-users with the highest
sonic fidelity with minimal distortion of the original recorded program.
Yet how many owners of this sophisticated audio equipment realize that the
last device in the audio chain is not the loudspeaker, but the room in
which they are listening to the material?
The listening room will severely affect the
final quality of sound that is heard from an audio system by either
absorbing, reflecting, diffusing (scattering) or transmitting sound waves
that impact its boundaries. Just as you may choose a color of paint on a
wall to achieve an aesthetic look or select a light fixture to provide the
appropriate amount and coverage of light, one should also ensure that the
surface materials on the walls, ceilings and floors of an audio listening
room are carefully chosen to achieve a balanced sound level in the room
throughout the entire frequency range of human hearing.
Because the knowledge-base of acoustics is
so limited in the architectural industry,
audio-listening rooms and home theaters are often built with no real
attention given to the natural sound of the room. We have even heard of
times where the
audio/video designer will even suggest to the architect or homeowner that
they don't need to spend any money or effort on acoustical treatments,
since they can simply compensate for the bad room acoustics with
equalization. As will be shown in a future article, this approach is only
marginally effective since it is essentially creating a deficient sound to
compensate for a deficient room.
Yet where does a homeowner or a designer go
to achieve a room design that will enhance the state-of-the-art audio
system in every way possible without adding distortion to the sound that
reaches the listeners' ears?
Acoustical consultants have been assisting
architects and building owners for decades in the design of performing
arts theaters, concert halls, recording studios and many other types of
commercial, industrial and, more recently, residential spaces. With the
advent of multi-media theaters and critical audio listening rooms in
residences, it has never been more appropriate to engage the services of a
qualified acoustical consultant to, not only work with the home designers
to achieve great natural-sounding spaces, but to also contain the
tremendous levels of sound and vibration produced by modern full-surround
audio systems. This is often very important with families where perhaps
the children want to invite their friends over to watch the latest action
movie in the home theater while the parents want to relax upstairs or do
work in a home office.
The best acoustical consultants are not in
the business of selling products, but instead have objectively evaluated
all products and construction methods and are able to specify the right
combination that is appropriate for each project.
Audio Visual Design has it's own on board
full time acoustical consultants along with having affiliations with the
top east coast acoustical dealers. Having professional musicians, and
chief studio recording engineers on hands to lend their knowledge and
discriminating ear. Audio Visual Design can provide you with the most
optimal acoustic room possible.
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ACRONYMS
NC (Noise Criteria) (Whole Number
>0. e.g., NC-25)
The NC level of a room is a number rating
of the noise level of an interior space. The NC number is associated with
a series of sound energy level-versus-frequency curves known as Noise
Criterion curves. For new construction, a Noise Criteria is established
based on the room's type and its intended function, and is used as a goal
in the design of sound isolation construction and the attenuation of
mechanical systems noise. To determine the NC rating of an existing space,
octave-band frequency noise levels are measured and plotted against the
series of NC curve spectra.
In a Home Theater or other similar space,
it is important to have a very low background noise, or NC level, since
this directly affects the dynamic range of the audio. If your noise level
is high, you will have to turn up your system to hear the quietest
passages. Unfortunately, this will also make your loudest passages even
louder, which may be uncomfortable to your ears and require additional
amplifier power and sound isolation from other rooms.
STC (Sound Transmission Class) (Whole
number >0. e.g., STC-56)
The STC is a single number method of rating
the sound isolation performance of a wall, floor, ceiling, door or window.
Like the NC, the STC number actually refers to an entire spectrum sound
level, in this case, divided into one-third octave band values. The higher
the STC number, the better a partition isolates sound overall.
STC numbers should be used only as a broad
comparison between two or more partitions. One reason for this is because
the same sound source played through an STC 50 drywall partition and an
STC 50 concrete block partition will sound quite different on the other
side because of the way each type of wall isolates different frequencies
of sound. The one-third octave band levels (known as Transmission Loss
(TL)) are essentially the difference in level between a sound measured on
the same side of a partition and the levels measured on the opposite side.
For a thorough sound isolation design, the TL numbers should be evaluated
based on the frequency and level content of the source noise and the
specific NC level required in an adjacent space.
NRC (Noise Reduction Coefficient)
0.00 <= NRC <=1.00* e.g., NRC = 0.85)
The NRC value is a single number method of
rating the sound absospecific frequency band if it reflects virtually all
sound at that band. Concrete and brick are examples of materials with low
sound absorption coefficients at all frequencies. Materials such as thick
(4" or greater) fiberglass insulation and some foams have high
absorption coefficients near 1.00 at most frequencies. The NRC rating is
defined as the arithmetic average of the material's measured sound
absorption coefficients at the 250Hz, 500Hz, 1000Hz and 2000 Hz octave
bands. These frequency bands represent the range of sound most associated
with speech.
If the material is required to absorb very
low or high frequencies of sound, the individual sound absorption
coefficients should be used for comparison, rather than the NRC value.
This is very important to note in a Home Theater where the audio contains
a lot of low-frequency sound energy. You may be tempted to use an
acoustical wall panel or ceiling tile with a high-NRC rating throughout
your Theater space. However, since the NRC doesn't tell you how or if the
material absorbs low-end sound, you could end up with a very bass-heavy
room unless you try to achieve similar amounts of sound absorption at all
frequencies of interest.
* Note that data published for some
acoustical materials may show absorption coefficients greater than 1.00 at
one or more frequencies. This is because the effective absorbing surface
area in a thick or shaped material is greater than the material's face
area used to determine the absorption coefficient.
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DEFINITIONS
dead room: A room containing a large
amount of sound-absorbing material.
diffusion material is a material in
a room that causes sound waves impacting on its surface to be scattered in
multiple directions. Examples of diffusive shapes include convex or
splayed walls and ceilings, coffers, columns, pilasters and very ornate
architectural surfaces. Hard furniture and sound-absorbing panels spaced
at intervals along a reflective boundary surface will also add some
diffusion to a room.
flanking path: a path between
adjacent spaces other than through a common partition that sound or
vibration is transferred
flutter echo: a rapid series of
reflections usually created when a sound is played between two hard and
parallel room surfaces. Flutter echo is often perceived as a
"buzzing" or "ringing" sound and can be detrimental to
the clarity or intelligibility of a sound. Simple solutions for
eliminating this occurrence include: creating an offsetting angle of at
least 5° between the two surfaces, adding sound absorptive materials to
one or both surfaces or adding diffusive shaping to the surfaces.
live room: a room containing very
little sound absorbing materials.
room modes: Fluctuations in the
energy level of sound dependent on frequency, source position and listener
position in the room. Modes are produced at frequencies relative to the
room's primary dimensions and are caused by the reinforcement and
cancellation of multiple sound waves. They are often referred to as
standing waves, since a sound produced at the fundamental modal frequency
appears to be stagnant in the peak energy position.
reverberation time: The amount of
time at a specific frequency that a sound in an enclosed space takes to
decrease 60 decibels (basically to inaudibility) in level after the source
sound has stopped. The reverberation time gives a listener the sense of
the size, liveness and warmth of a room. Reverberation time increases
proportionally with the cubic volume of the room and decreases
proportionally with the quantity of sound-absorbing surfaces in the room.
So, unless a Home Theater is unusually large (which it shouldn't be) or
highly-reflective (which it shouldn't be) there will be very little sound
buildup or decay. Thus, reverberation time is not a very useful measure
for the acoustic quality of a Home Theater.
source and receiving room: terms
used in sound and vibration isolation analysis to designate the room
containing the sound or vibration producing source (source room) and an
adjacent (receiving) room requiring that the source noise be attenuated by
the intervening partitions to a specified noise level.
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MYTHS
AND MISCONCEPTIONS
M&M #1: Fiberglass or foam placed on
a wall will prevent sound from going through it.
Reality #1: These materials only absorb sound and do not provide a barrier
to it. Heavier building materials and resilient attachments to structure
are the best methods for isolating sound.
M&M #2: Carpet on a floor will
reduce sound transmission to a room below.
Reality #2: Carpet is a sound absorbing material mainly at high
frequencies, and has very little airborne sound isolation properties.
Carpet does, however, reduce the amount of impact sound from footfall or
things dropped that is transmitted to the space below.
M&M #3: Egg cartons on the wall
improve the sound of the space.
Reality #3: While egg cartons do have some sound-absorbing and diffusing
properties, they are concentrated in a relatively narrow frequency band
and do not positively effect the quality of speech or music to any
significant degree. They also have negligible sound isolation properties.
M&M #4: Adding insulation to a
sheetrock wall will keep all sound from going through it.
Reality #4: Insulation between stud cavities in a sheetrock partition does
improve the sound isolation value of a partition and should be used
whenever possible. The improvement, however, is too small to bring about
an appreciable difference in the degree of isolation, and the insulation
should only be thought of as a partial solution to upgrading the isolation
of a partition.
M&M #5: SOUNDPROOFING!!!!
Reality #5: This word is the catch-all phrase used by many for improving
anything that has to do with acoustics. "Soundproofing" implies
building a room that will keep all possible sounds outside the space from
transferring in, and all sounds generated in the space from transferring
out. Building construction can be designed to attenuate a fixed degree of
sound, but cannot theoretically prevent all possible sounds from passing
through the boundaries of the room, except in extremely rare (and
expensive!) situations. Better terminology to use when describing a
client's acoustical needs may perhaps be "Noise Reduction" (for
sound isolation) and "Sound Enhancement" (for room acoustics). |
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