Originally appeared in the May 1988 issue of Installation News magazine.
Reprinted with permission.
© All rights reserved.
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Originally appeared in the May 1988 issue of Installation News magazine. Reprinted with permission. © All rights reserved. |
From end to end it is 21 feet long and it weighs approximately four tons. It is painted black with red pearl high1ighting. Its stereo system pushes an incredible 4280 watts RMS. It is called, appropriately enough, the Terminator.
The car is a 1960 Cadillac Hearse. After finding the car in a field near Dallas, Wayne Harris, an electrical engineer for Orion Industries, managed to purchase it for $850. Since then, he has invested another $50,000 to $60,000 in restoring and rebuilding the Terminator. There were innumerable hours involved in restoring the car, but Harris said the result has been well worth all of the effort.
The Terminator after three years of work and $50,000.
The stereo system, Harris said, received complete priority in the restoration process. Everything else was secondary. And although the system was not designed to yield an extremely high SPL, it can easily turn out a 146 dB C weight average. It should be pointed out, however, that half of the total power in the system is used at 48Hz and below, with a 30 dB/octave roll off, and will not show up on a meter with the C weight filter in. The 24-inch drivers used in the car are capable of handling unbelievably low frequency energy in the 10Hz to 50Hz range, according to Harris. After obtaining all of the desired equipment, Harris went to work.
Before any of the installation work began, the car was completely shaved. Harris started at the back and worked forward. He stripped out the interior of the car from the firewall back. The door handles were removed and replaced with electronic actuators, which are activated by remote control. After carefully selecting drivers and using a computer aided box design, Harris proceeded to construct the enclosures.
View from the cockpit when looking backwards.
The first enclosure built was for the three MTX 24-inch subwoofers. The total enclosure volume required was 50 cubic feet, with three chambers of 13 cubic feet each. Each chamber is ported and tuned to 18 Hz.
The enclosure for the eight MTX 12-inch woofers and the pedestal for the Recaro seats came next. These drivers are chambered and ported in pairs. Each driver has approximately 0.8 cubic feet.
All of the boxes are made of ¾ inch plywood. All joints were beveled and glued with wood glue. Drywall screws were used every six inches. The interior joints were sealed with silicone sealant. Bracing was used every 12 inches to reduce enclosure wall resonance.
Enclosures for the Terminator's 24-inch subwoofers.
The overhead console was the next task that Harris decided to tackle. "In order to achieve good stereo separation and front imaging," Harris said, "I wanted each listener to have his own left and right midrange and tweeter. Also, to get good front imaging, the drivers needed to be mounted in front of the listener." He mounted MTX 5-inch midranges and MTX dome tweeters on both sides of the console.
In the very center of the overhead console is a key pad and a bank of push-button switches. The key pad is used instead of a key to enable operation of the vehicle. This prevents unauthorized use of the system. The green buttons in the console are used to turn on the cooling system, the inverter, the dash, the Apple computer, the illumination and giant RTA show lights. The red buttons are used to override the Apple computer and manually turn the amps on and off.
Overhead, on the driver's side, is the driving computer and cruise control. Overhead on the passenger's side is the keyboard for the scrolling sign, such as the ones seen at banks, that shows through the top of the windshield. This is used to describe the car at shows.
The Terminator's dash under construction.
When the woodwork was done, the upholstery came next. Padded gray velour covers the roof. Darker gray fabric is used everywhere else. The carpeting is black. After Harris had trimmed everything, it was time to fill in the spaces.
Constructing the dash probably took the most time. Harris said he wanted the finished product look like a jet cockpit. Realizing that symmetry is the key to good looks, Harris attempted to make the dash as balanced as possible. There are two main panels to the dash, which is split down the middle by a center console.
The far left panel of the dash is the vehicular control panel. From this panel the car can be started, the lights turned on and other control functions can be initiated.
The driver's console contains an array of devices and controls. The top left portion holds a CRT which is the display for the rearview camera. The center CRT is an ETAK navigator. The right CRT is the text output for the Apple computer. The bottom left meter is the speedometer and the bottom right meter is the tachometer. Both of these instruments are homemade and consist of both digital display and an LED bargraph movement. Located in the bottom center are the water temp, fuel and oil pressure gauges.
The Terminator's computerized brain.
Directly in front of the driver's panel is the control wheel. The wheel is out of a Beechcraft King Air airplane. On closer inspection it is noticed that an Escort radar detector remote control has been mounted on the steering wheel, while the detector itself is mounted in the overhead console.
The center console contains two color video monitors. The top monitor displays graphics from the Apple computer, while the bottom monitor displays video from the VCR. Directly below are the control heads for an Alpine 5950 disc changer. A Panasonic VHS Hi-Fi VCR is mounted beneath these.
The passenger console was used for the stereo system. The top panel contains 15 bargraph wattmeters. These meters indicate how much power each speaker is receiving. The sensitivity is adjusted by moving a knob that changes a digital readout. When the bargraph hits the top red LED, the power that that particular speaker is receiving is displayed by the digital readout. Mounted below the power meters is a computerized 12-band equalizer with a real time spectrum analyzer and subsonic synthesizer built in. This EQ also has remote control capabilities. Below the EQ is an Analog Digital Delay network. This delays audio by a controllable amount and then sends the information to the speakers in the headrest of each seat. "This produces an ambiance that is usually present only at live performances," said Harris.
The security systems were mounted in a small panel to the extreme right. A Pulsar Intercept 1000 and a Pulsar Intercept 250 are used to protect the vehicle. Each system has its own pin switches, battery backup and sirens for total redundancy. The Terminator's crossover network.
There's an Apple computer on board and peripheral cards, which give the Apple 48 digital I/O lines and sixteen 12-bit resolution analog inputs, were added to the computer. The remote terminal for the Apple is located directly in front of the VCR. The Apple monitors speed, RPMs, fuel and water levels, engine temperature, oil pressure and DC volts. If any of these readings fall outside of a predetermined window set by the operator, a warning message along with possible causes and solutions will be displayed on the video monitors.
The Terminator's "cockpit".
The stereo system also can be monitored by the computer. The temperature of all seven amplifiers as well as the ambient air temperature from the amp racks and the exhaust port air temperature are displayed both numerically and graphically on the video monitors. If temperatures exceed preset limits, a warning will flash on the CRT. If the problem continues, the computer will automatically shut down that particular amp. The computer also interfaces with many other devices on the vehicle. One is the Escort radar detector. If radar is detected, the CRT will indicate this and predict the distance to the source. A Chips Detector is also wired in. Upon detection of a Highway Patrol car, a warning message and estimated time until detection will be displayed.
The installation of the Terminator's stereo system was fairly straightforward, said Harris. The Alpine cassette changer, the Alpine compact disc changer and the VCR provide the signal source to the EQ. Source selection is made by a switch on the EQ. The audio is then routed through a subsonic synthesizer.
"The synthesizer is necessary for this system because of the ability of the subwoofers to reproduce extremely low frequencies," Harris said. "Most recordings, even on CDs, have very little program information below 50Hz. Since there is nothing there, an EQ can't boost it. The synthesizer takes all program material from 55 to 100 Hz and recreates this information one octave lower."
The signal is then fed into the digital delay processor. From there it travels to the rear of the car via foil shielded cable. The six active Orion crossovers receive their inputs from the signal distribution box.
The Terminator's crossover network.
The first crossover is a 30dB low pass filter set at 48 Hz. All information below 48 Hz is sent to the sub- woofer amplifiers, which drive the three 24-inch subwoofers.
The second set of crossovers is comprised of a 30dB low pass filter and a 30dB high pass filter connected in series. The 30dB low pass is set to 340 Hz and the 30dB high pass is set to 48 Hz. This results in a bypass configuration which passes audio from 48 to 340 Hz to the woofer amps. These amps drive the eight MTX Terminator 12-inch woofers.
The third set of crossovers is also comprised of a 30dB low pass filter and a 30 dB high pass filter connected in series. The 30 dB low pass is set to 5KHz and the 30dB high pass is set to 150 Hz operation. All information from 150Hz to 5KHz is passed to the midrange amps, which drive four midranges.
The fourth crossover is a 30db high pass filter set for operation at 5K. All information above 5K is passed to the tweeter amp that drives the four MTX 1 inch dome tweeters.
The total system power comes to 4280 watts RMS. This is provided by six Orion GS-2350 amps and an Orion 24 Gx amp. Monster cable is used for all speaker connections. Every speaker is fused on the flip side of the amp rack for protection against excessive power.
The amp rack is mounted vertically in the rear of the car. The amps are shrouded in glass, with forced air cooling. To service fuses or make tests, the amp rack rotates 180 degrees to reveal all of the support circuitry. Located on the flip side, from left to right, are the DC power distribution buss bars, speaker fusing, active crossovers, computer and switch interface circuitry.
The middle side windows of the car contain huge real time spectrum analyzers. Each side has ten bands with ten lights in each band. The dimensions of these panels are 17 by 40 inches.
Harris said that while he was planning the install he realized that he would need an extremely strong electrical system. "Calculation indicated that I would need somewhere around 7000 watts of input power. That's about 550 amps at 13 VDC. To put things in perspective, that's the same amount of energy required to light 117 60 watt light bulbs."
Obviously, Harris was going to need the largest alternator setup he could find. Letsek Manufacturing in Fort Worth, Texas, was able to provide Harris with a 380 amp system. This consisted of dual 190 amp alternators and a dual Pulsar regulator.
Because Harris wanted to be able to play the stereo at its full potential without running the car, a bank of batteries capable of supplying the required current was necessary. Six deep cycle marine batteries in parallel gave Harris the 360 amp hour rating he needed.
"After going to the trouble of producing all of this power," Harris said, "I wanted to make sure that none of it was lost in the power cabling. Welding cable is ideally suited for such purposes because of its good flexibility, fine copper strands and durable jacket. Cables of 00 gauge run from the alternator, across the batteries and then terminate at the buss bars in the amp rack."
All positive cables are connected through fuses to the B+ buss bar. Similarly, all ground cables are connected to the ground buss bar.
Construction of the Terminator began in the fall of 1984, shortly after Harris won first place with another vehicle at the Crank It Up nationals. Since then, the Terminator has undergone numerous evolutionary changes. Harris said that he has invested practically all of his earnings for the past three years in the project. But, he adds, it was worth it.
Wayne Harris "getting into" his work.