Overview of Nissan - Bose Systems (89-94 Maxima, 90-96 300ZX)
Below is a description of the typical Bose system. All information is referring to the 90-96 300ZX and the 89-94 Maxima. Other vehicles, in particular the 93-95 RX7, and early 90-96 Infiniti are very similar.
Head Units: The Bose systems in question start with a Clarion built head unit. "Version I" (left) was used in 89-90 models. A cosmetically upgraded "version II" (right) was introduced in 1991, and changed slightly again in 94. These were well built units, but since these units are currently up to 20 years old, many will still have problems.
The 300zx and Maxima decks can be distinguished by slightly different LCDs...the Maxima's have a green display, while the 300zx head units have a whitish/blue display. Both heads are still fully interchangable between the two cars. These are basically standard cassette players, but have a low level output, rather than speaker level.
CD Players: Sony built the older 5 pin CD slave units that plug in to the head and were located in the lower DIN slot. Around 93, the CD slaves and head units went to an 8 PIN connection. The newer CD head units were no longer made by Sony, yet were built by Panasonic.
If you plan to add an OEM CD player to your car, you will need to know what version of deck you have. The obvious way to tell is removal of the unit, so you can view the number of conector pins in the round connector. To add such a deck, you will need an adapter harness as seen on the right.
Speakers: Bose used top of the line drivers directly from their home speaker lines in Nissans as well as other automotive systems from the same era. The most prevalent drivers were derived from the Bose 901 series which are 4.5" drivers with almost triangular outer frames (lower left). Basically, these are the 901 drivers with a tougher cone material, as well as cloth surrounds, designed to stand up to the automotive environment.
These speakers were used in the front of the 89-94 Maximas as well as the 90-96 300zx. In 1991, Z cars used these all around, front and rear. This was Bose's favorite driver for all automotive systems in the 80's and 90's, and these were also used in Bose PA, and outdoor speakers.
This driver can also be found in Corvettes, Cadillacs, and 3rd generation RX7's, and the NSX just to mention a few. Early production (1990) Z32's had 6.75" drivers in the rear (right) which were a more basic speaker. However, Bose ditched the 6.75" version completely in 1991, as mentioned above. In the rear of Maximas, 6x9's were used from 89-94. All speakers had a 1 ohm impedence, more less.
Amplifiers: Nissan / Bose systems have 4 small amplifiers, one located inside each individual speaker enclosure. These are relatively basic amplifiers, with a total of only (6) connections each. In 89-90 systems, a harwired version is used (left picture). In 1991, all amps went to a modular design (right) to make for easy replacement. The amps are location specific, and are tuned in the pre-amp stage to fit the acoustics of the car as well as the driver. Since this is the case, mixing and matching amps from different vehicles will sound poor. Even using mixed amps between the various versions of the Z car may result in poor sound, even if you observe mounting location.
Center Channel: The Bose center channel speaker came in 89-90 models that didn't have factory CD. However, this was done away with completely in 91. Just like the other Bose speaker assemblies, this unit also contained an internal amplifier all in single DIN chassis. This item uses both right and left input to offer center channel output. The picture below shows the internal workings of this item.
Enclosures: Bose systems have enclosures for their speakers when possible for sound quality. The rear location of Maximas have 6 X 9's in the trunk as is the case with other Nissans and Infiniti coupes, yet all have port tuned front enclosures. The Bose enclosures are precisely tuned for the drivers that they housed. Seen below is a typical enclosures in a Z32.
The Bottom Line:
Bose systems started with decent head units, top notch for their time period, but dated in today's multimedia car stereo world. Bose also used the best possible speakers they had available with enclosures perfectly tuned for the drivers. Unfortunately, the amplifiers were crippled by the speakers low impedence loads. Also, they are located in places where they are subject to extreme conditions (moisture, constant door slamming, etc.), so they typically have a short lifespan.
When working properly, the Bose systems are a nice sounding factory system. However, due to the age of Z32's and Maximas, most currently have failing or dead Bose systems, and often the price to restore the system using new parts is out of reach or not feasable. But used parts can often help one get around this. if you need any parts, contact me - as I may have what you need.
Feel free to email me with any further questions about your system: zmaxsystems at musfiber dot com