Throughout this
project, each component will be required to be compatible with the other
components chosen. The dual purpose for
this is to keep cost factor low and facilitating installation. Several adaptors can be eliminated by having
compatible components. Five major
components will be used in this system, the head unit, the front speakers, the
rear speakers, the subwoofer, and the subwoofer amplifier.
Head Unit
The head unit is
the most important component and must have certain features to make it adequate
for this system. Some of the features we
will not be using immediately but will require in case expansion is later
desired. There are four major features
required in the head unit, the are internal amplifier, Pre-amp out RCA jacks,
CD controller and a face-off security feature.
Figure 1Internal
AmplifierThe head unit must have an internal amplifier that can produce at
least 25 watts-per-channel so it can adequately power a decent pair of
speakers. Reproduction of higher
frequency sounds (i.e. violin, flute) as well as lower frequency sounds (bass
violin, tuba) require more power to be heard at the same level as a midrange
sound (voice, trumpet). The internal amplifier in the head unit must be able to
generate enough wattage for the SPL (sound pressure level) of the higher
frequencies to be heard clear in a space the size of the AEROSTAR.
Pre-amp Out RCA
Jacks
To allow for
low-level amplification without using an in-line power reducer, the head unit
will require low level pre-amplification output jacks. Head units ordinarily come with either front
and rear, or just rear RCA jacks. This
situation will only require rear jacks since the head unit produces enough
wattage sufficient for the front speakers.
The sub-woofer system will be powered by an additional external
amplifier by using these jacks.
CD Controller
Although
cassettes are more versatile at this point in time, CD's are readily available
and deliver a more quality sound. It
would be a very good choice to assure that a CD Controller is built in. One
that controls more than just a specific multi-CD player.
Face-off Security
Full-Panel
detatchable security feature will also be required. Most head units have this as a standard
feature making this feature, although indisposable, readily available. A unit that has mechanical fast-forward,
rewind, and eject buttons will be preferred over a unit that has all these as
electronic features. The reason for this
comes apparent if ever a cassette tape is left in the unit and the tape is to
be ejected without having the ignition key to power the unit.
In the tuner
section of the unit, local/distance switchting , dolby noise reduction and at
least 12 FM presets will also be advantageous features in our head unit.
The head unit we
will be using will be the Pioneer model KEH-P4200. It has a 35 watt-per -channel amplifier built
in so it is sufficient for driving front speakers.
This unit
features Multi Function Display (MDF) which allows the operator of the system
to view many different functions of the unit.
The display is an orange colored digital display with the ability to
display alpha-numeric, user programmed titles for the optional compact disc
shuttle as well as the time, date, call letters for the radio station tuned in.
Another feature
included is a new F.I.E. (Front Image Enhancer) that cuts middle and high range
frequency output from the rear speakers so that only low range frequencies are
output, for an appearance of voices and higher pitched instruments to be in
front.
The unit is
standard size (7"w X 2"h
X 5-7/8" d) and uses the standard
auto grounding system and power consumption, allowing an installation without
cutting or drilling and appearing factory installed.
The unit utilizes
the face-off anti-theft system, which allows the front panel of the unit to be
removed as a theft deterrent. Pushing a button in the upper right corner of the
panel will eject the panel from the body. To replace the panel, push the panel
into the main body.
Caution: Be very
careful in handling the front panel.
Do not leave the
panel in direct sunlight or high temperatures
Do not drop the
panel or otherwise subject it to strong impact
Do not allow
volatile agents (i.e. benzine, thinner, insecticides to come in contact with
the surface of the front of the panel.
Figure 2Do not
touch the contacts on the front panel or
on the unit body (see fig. #)The Pioneer model KEH-P4200 has features that meet the requirements of
this project.
Front SpeakersIn
this project, the selection of front speakers is dependent on the sound
preference of the driver. Since the
front speakers will dominate the passengers in the front seat, it is important
that they produce a sound acceptable to those passengers. The subwoofer system used will require the
front speakers to only cover sounds in the mid to high frequency range. The head unit will be required to produce
enough power to drive the front speakers, therefore, direct compatibility
between the head unit and the front speakers is important. The Ford Aerostar can accomodate speakers in
the front up to 6-1/2" in diameter without cutting.
The front
speakers will be the Infinity REFERENCE 502i - 51/4" Two Way Speaker. They have a power handling capacity of 45
watts which is sufficient for frontal imaging.
These speakers
are designed to drop into the existing speaker cutouts. The advantage of having speakers that fit
into existing cutouts in the front dashboard cannot be stressed enough. This eliminates the need for completely
removing the front dashboard for cutting . They come with matching grilles,
which will not be necessary in this situation.
The F.I.E. (Front
Image Enhancer) in the head unit takes advantage of the dual cone speaker design for a full range frequency
response. They also come with a built in
crossover to increase the output efficiency of the speaker.
Figure 3Rear
SpeakersThe Ford Aerostar comes with accomodations for two sets of rear
speakers. One pair of 5-1/4"
speakers can fit into cutouts in the rear door.
There are also cutouts in the rear on the sides for speakers 6"x
9". Once again, due to the
subwoofer system being used, these two sets of speakers will only be required
to reproduce sounds in the mid-range and higher.
The 5-1/4"
speakers in the rear door will only reproduce sounds in the upper-midrange to
high range. The head unit will produce
enough wattage to effectively cover this range in a set of speakers this size.
The 6"x 9" 's in the rear sides will
reproduce the full range of sound excluding the low range reproduced by the
subwoofer. To effectively do this
without loss of sound quality, a set of 2-way
6"x 9" speakers will be used.
The speakers will start reproducing sound in the range of
1200hz-1500hz. The subwoofer system can
adequately supply all the tones generated below the 1500hz point, and
compensate for the lows lost by the absence of amplification in the 6x9's.
The rear door
speakers will be the Kenwood KFC-1054.
They are 5" in diameter and have a mounting depth of only 1"
which makes this also ideal for installation into factory cut speaker openings.
Figure 4These
speakers have a power handling capacity of 35 watts over a frequency range
of 60HZ to 20kHZ. In this system, there will be a capacitor
installed to cut lower frequencies off at 2kHZ.
Allowing only lower to midrange sound reproduction.
The rear center
speakers will be the JBL GTC9610. The are the standard 6"x 9" two-way
models which makes this also ideal for installation into factory cut speaker
openings. They are designed for full sound reproduction to be used in a
multi-set speaker environment, or, since they cover a wide enough spectrum of
sounds, they can be used in a very small system involving only one set of
speakers.
These speakers
are designed wiwth a titanium tweeter and a polypropylene cone for the main
driver. These materials are generally used in systems that will be played at
loud volumes for long periods of time (ie. studio monitors, concert speakers).
Figure 5The JBL
GTC9610 cover a frequency range of 45HZ to 19kHZ being driven at 4(up to
100watts into each speaker driver. They
also come with matching grille covers and mounting hardware.
Subwoofer System
The subwoofer
system used will be made up of the subwoofer speakers and the amplifier used to
power those speakers.
Speakers
The speaker
component of this sub system will be self contained speakers in the 8" to
12" range. The maximum dimensions
of the speaker system are 10"h x 30"w x 20"d. These dimensions will allow the speaker
component to fit under the rear seat.
The speaker can consist of either a single mono woofer, or a pair of
seperately contained stereo woofers.
Subwoofer
Speakers
The subwoofer
speakers will be the SAS-BAZOOKA T-102 10" bass tubes. They have dimensions of 18"x 83/4 x 10" and a power handling capacity
of 200 watts. They also have an upper
frequency cut-off of 1.5kHZ. They are paper cone drivers enclosed in a
ported box.
Figure 6The tubes
are designed to enhance low frequency program material. The T-102 is designed to be installed in
hatchback cars, pickup trucks and minivans.
Once again due to the design of the enclosure, no modifications will
need to be made for installation. The
tubes come with a tie down package for an easy and secure installation. The tie down package includes cam style
buckets to easily remove or install the system with minimal effort.
Amplifier
The amplifier
used to power the subwoofer speakers will only have three major
requirements. They are size, signal
input connector and output power rating.
The size must be
adequate to fit either along the side of the sub-speaker system or in the space
along the side of the rear seat anchor.
In this space we have a maximum of 10"h x 8"w x 18"d.
The signal input
connector must be RCA type connectors and have a low-level input switch. The
preference here is a set of male jacks on a cord protruding from the unit at
least 6" long.
The output power
rating must be suitable to produce at least the minimum power rating for the
speakers used. In this system, the
speakers will reproduce sounds in the range below 1500hz at a minimum of
50watts per channel.
The amplifier
used in the subwoofer system will be the Kenwood KAC-ps-150. This amplifier is
a two channel model with an output rating of
75watts per channel. It has an
internal crossover which enables it to be used directly with any type of
speaker.
The dimensions of
this unit are 11"x 21/2"x 9". which makes it ideal for placement
in the space on the side of the Bazooka bass tubes.
6
Findings and
Conclusions
The selection
process of a stereo system for the 1987 Ford Aerostar can ultimately be
justified by the importance of sound quality to the owner of the vehicle. It has been shown that a quality stereo can
be purchased from local vendors for a price of around $1100.00.
The cost of
instalation by a professional installer could range from $200.00 to well over
400.00. There are also various details
and accessories that are also necessary to complete this project. These accessories will cost around 100.00.
In this project,
all components can be installed by the owner.
This substantially decreases the overall cost of the stereo system as
well as gives the owner an added feeling of accomplishment and pride. There are several manuals available to
show how
to install stereo systems, and due to the age of the vehicle, they are
highly reccomended.
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