I recently finished installing a class-D Massive Audio BX4 amplifier
and Infinity Reference X REF-6500cx component speakers
along with my Nakamichi NA350iBTR Head Unit
- The head unit must not be too flashy or show too much of a departure from stock aesthetics.
- The speakers and crossovers must fit in the stock location(s) without intense modification.
- The amplifier must fit in the stock location and exhibit cool operating temperatures.
- The amplifier must accept a 5V preamp output without distorting (unlike the stock BOSE unit).
- The amplifier must have gain controls and bridging capability.
- Stock wiring must be sufficient
Straight-forward installation. I added a ground to the chassis, but wired everything using the information supplied by Crutchfield. Note: this head unit is no longer available, but the NA250 is. I chose the Nakamichi unit due to the extremely bright display, clean no-frills pre-amp (5V output), SD card, USB, and Bluetooth capability. Though the unit has a preset orange that is very close to the stock orange lighting, you can get an exact match using the custom display function. The fact that this unit was on sale was also a deciding factor. Though you could terminate your own RCA plugs on the stock wiring harness, I elected to run a single 2-connector (left+right) RCA cable (9’) and a single 1 connector (mono/subwoofer) RCA cable to the amp and zip-tied them to the stock harness running down to the amplifier’s location.
Unfortunately, I don't have images of the speaker installation (long story...), but modification was required to the plastic speaker baskets/frames. In short, you have to remove the front and rear plastic on the speaker baskets (I used a hack saw and Dremel) to ensure that the magnet and rubber surrounds fit properly. Basically, you're removing all plastic aside from the basic "rings" of the two pieces. On the speakers themselves, you'll need to remove the protruding metal rings of the mounting holes (a single back-and-forth action with some pliers works perfectly) to ensure that the speakers sit inside the stock plastic mounting rings.
The speakers use the same mounting pattern and once sandwiched between the two stock pieces, it's a perfect fit
in the door - no impact with the window, no bulging etc.
The tweeters fit amazingly well in the doors using one of the 3 supplied mounting pieces. I did use some black gorilla tape across the back side of the tweeters to eliminate and frequency cancellation from inside the door cavity, but otherwise they fit right inside the stock 3-tooth snapping teeth.
The crossovers were mounted directly above the new drivers using zip ties which I ran inside the door through two available holes. I elected not to press/enable the +3 dB gain on the crossover as I would rather adjust the tweeters from the HU, and I prefer to keep things as flat as possible. See attached images.
The Massive Audio Class-D 4-channel amplifier is overkill in terms of output, but this is intentional. It's far better to have an over-sized (digital) amp that is properly setup than a low power amp running at near capacity, especially if a class-D amplifier is chosen (far lower chance of clipping/distortion). Class-D amplifiers run extraordinarily cool and are ideal for the stock mounting location.
The stock amplifier is physically larger than the Massive Audio unit, and though the new unit does not share the same mounting holes/location, you can secure it with zip ties or drill and tap your own mounting holes in the stock metal panel (I chose the zip tie route - these cars are loaded
with them anyway). See pics for reference.
I used channels 1 and 2 (left and right) for the front speakers, and only channel 3 for the rear speakers, which are currently
stock. I soldered the stock wires for both rear speakers (4 ohms each) together (parallel) to create a 2 ohm load on the new amp, and connected them in a bridged configuration. It is important to properly set the gain on both your head unit and the amplifier to ensure an initial balance and crossover point. In my case, I use the head unit's crossover capability so I set the amplifier's crossover setting to "full", meaning full range.
The Infinity and Massive Audio product combination are a huge leap in sound quality and overall output from the stock BOSE setup. Yes, they can produce much louder
output, but that was not the goal. What I wanted was higher quality, functionality, adaptability, etc. Now, I can adjust the rear “subwoofers” independently from the front speakers and the front speakers are far more neutral and accurate than the paper drivers that BOSE can’t seem to get away from.
Rear speakers will be a challenge as there’s such limited room for the magnet/motor structure of true mini-subwoofers. I have a pair of Massive Audio SUMMO 64 (6.5”) subwoofers (traded for unrelated gear) that I thought I could somehow shoehorn into place using a custom mount/fabrication. While I can accomplish this, I would be losing about 4 inches (or more) of leg room as these drivers will protrude quite a bit due to the large motor. I plan on mocking up something to see just how bad it will be, and will update this thread upon that conclusion.
That said, the stock BOSE rear speakers have come to life and actually sound fairly decent - I'm satiated for now.
More to come...
The Massive Audio SUMMO 64s are beastly animals for their size, but they're just too dang big for the mounting location. I've, instead, installed Earthquake Sound's SWS 6.5x
units instead. No modification is required as they fit in the stock baskets. However, the sound quality is only marginally
improved and not recommended.