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.
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.
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.
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.
The subwoofer system used will be made up of the subwoofer speakers and the amplifier used to power those 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.
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.
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.
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.