#07 | #08 | #09 | #10 | #11 | #12
I finally finished installing a pair of new door speakers along with an amplifier in my 94 B, and I'm quite happy now with my sound system.
Never having installed an amplifier before nor a component speaker system, I took my time, and finished the job over the course of 4 nights. I guess I could have paid a professional install shop to do it much more quickly and avoid all the hassles, but like changing oil, I just felt a need to learn how to do it myself, and take the time to do a careful job for a car that deserves it.
First, the equipment. For the door speakers, I went with the Polk MM3055. It's a 2 way component system (5 1/4" woofer + tweeter) with an external crossover. For the amplifier to drive the speakers, I chose a Precision Power A200, rated at 50Wx2 @ 4 ohms.
Many thanks to all the folks on the Miata list who responded a while back to my question on where to install an amp in the trunk of a Miata. It turned out that the amp I bought can *just* fit inside the spare tire wheel well. I cut a 13.5" diameter piece of plywood (#01), attached some handles (#02), added a black vinyl covering on one side (#03, #04), and screwed the amp on the plywood (#05). The whole thing can just barely fit in the wheel well (#07), and if I need to use the spare, I can unplug the two connectors from the amp, lift up on the handles to remove the amp/mounting board, and access the spare. I used 12 gauge power and ground wires, with a 25amp inline fuse on the power cable. The power cable attached to the positive battery post; the ground cable to a grounding bolt just behind the battery.
Next the speakers. With the panels removed (#12, #13), I looked at the door (#10, #11) and realized I had to do major sheet-metal cutting if I wanted to flush mount the tweeters in the same location where the MSSS sound system had its tweeter (just below the vertical part of the A frame). There's an access hole already there (#10), which needs to be widened, but I decided that cutting metal was well beyond my capabilities, so I went for a surface mount of the tweeter (#19) at approximately 5" above the existing speaker hole (#10). I salute the person on this list who had previously described his install of tweeters at factory location, and went ahead and cut metal; it looked quite difficult, and it was certainly beyond my capabilities. Although I mounted the tweeter at a lower location, the tweeters were still pretty remarkable at putting out good sound at the high frequency, plus, they're aim point is fully adjustable, so I directed them so it faced slightly up and towards the driver's side.
Installing the woofers presented it's own problems. The existing cutout was about 5.5" across (#14), and now I know why Mazda puts its OEM speakers in a plastic bracket; without them, the hole was so wide that my woofers had nowhere to mount to. And I didn't want to use the OEM plastic mounting brackets, because the weather protection it offered was pretty minimal. So I purchased speaker adapter brackets and speaker baffles from Crutchfield (#15). With the brackets attached (#16), my speaker was able fit correctly into the speaker hole (#17).
Wiring for both woofer and tweeter had to pass through the rubber door wire protector (#18) which have me quite a headache because it was pretty difficult to snake the wires through. It really helped to snap out both ends of the door protector from the door and the dash.
The speakers had external crossover units (#20, #21). I velcroed the passenger side unit on top of the some black plastic box just behind the glove compartment (air conditioning unit ?) and the driver's side crossover box was velcroed on a vertical wall next to the fuse box.
Lessons learned:
Happy driving (and music playing!).
