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 decent units, but since these units are currently up to 18 years old, many will still have problems. The most common issue is low cassette output. When this happens, the deck virtually is an AM/FM tuner, because the cost to repair this issue easily will exceed the value of the unit. Otherwise, these decks are pretty solid, with nothing other than expected wear issues.
The 300zx and Maxima have a slightly different LCDs...the Maxima's have green, while the 300zx head units have a whitish/blue display. All heads are still fully interchangable. 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 and the newer CD head units, no longer made by Sony were much better and typically were Panasonic units.
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 (please contact me for this).
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 years use in an automotive environment.
These are used in the front of the 89-94 Maximas as well as the 90-96 300zx and Infiniti. In 1991, Z cars had 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 are much lower quality than the 4.5" drivers. 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 used had roughly a 1 ohm impedence.
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. Seen is an amp from a 95. The second version also changed slightly in 93. The way to distinguish the second generation of amps is that in 93 the model number was permanently printed on the amp cover (as seen on the right) while the 91-92 amps had stickers like the first version. The amps are location specific, and work together like a choir with slighly different sounds from each location blending to make one sound.
Chances are your Z will have unmatched amps. This is very common since unknowledgeable DIY'ers attempt to "fix" their Bose amplifiers by replacing bad amps with whatever they can find. Mixing and matching amps from different vehicles will sound awful! Even using mixed amps between the 3 versions of the Z car will result in poor sound, regardless if you observe location.
Bottom line, for a correctly working Bose system, you need 4 amps that match, period. You can upgrade to 91 amps in your 90 for example, but once again, all 4amps need to be a set. And as mentioned before, mixing amps between 2+2 and coupe versions will also result in unbalanced sound.
Center Channel: Some Nissan's came with a Bose center channel speaker which was done away with in 91. This unit also contained an internal amplifier all in single DIN chassis. This item simply used both right and left input to offer center channel output. The picture below shows the internal workings of this item. The system still sounds just fine if this item is eliminated, because in actuality, these did very little other than fill the lower DIN slot.
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 having 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. Accurate sound reproduction is not possible without an enclosure...have you seen any home speakers not in a box lately?
The Bottom Line:
Bose systems start 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 that they had available with enclosures perfectly tuned for the drivers. Unfortunately, the systems still have amplifiers that are 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 very nice sounding for a factory system, and most Z / Maxima owners actually degrade their car's sound quality when they replace the system. However, due to the age of Z32's and Maximas, most currently have failing Bose systems, and often the price to restore the system using new parts is out of reach or not feasable.
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If you are now ready to move on with your stereo system, check out the links below:
Feel free to email me with any further questions about your system: zmaxsystems at musfiber dot com