Hi there, I'm a big fan of [Miata.net], and use it to search for stuff and help on my '92 Miata. However, there is one thing I didn't find much help on...a monster stereo. I know that you've got articles on the Clearwater stuff, but nothing on speaker boxes or getting more volume out of those little door speakers, you know, enough to hear your music with the top down cruising at 70, etc. I figured now that I pretty much finished with creating my custom system, I would let ya guys know what I did and how it sounds so that if anyone else like me who wants a lot of sound and bass asks you, maybe my long hours of frustration will go to some good!
Anyway, I had to pretty much build the entire system myself, with little or no tech help from anyone (everyone I inquired hadn't had much experience with setting up the kind of stereo I wanted). One of my biggest problems (and the biggest area of lack of info) was getting lots of bass. I'm not a bass fanatic, but those little door speakers just don't quite do it. So I had a custom speaker box made for the trunk (which fits nicely) and dropped two 8" Rockford Fosgate subwoofers in there. I matched this up with a 240 watt Kenwood monoblock amp (don't know the model # off hand) and tied the two subs in parallel to get 2 ohms (the monoblock produces its highest power at 2 ohms, each speaker is 4). The bass is incredible! I didn't really figure I'd get that much from it, but the subs produce enough to be heard from 20 feet away.
Now on to the inside. I picked up a couple of JBL Proaudio 6 1/2" speakers for the door, and connected them to a 300 watt Kenwood Stereo Amp. Unfortunately, the particular Kenwood I bought only produced 300 watts at 2 ohms, and the speakers were 4 each. So I started to look for places to put more 6 1/2" speakers. There's some room right behind each seat, where that big silver plate separates the trunk from the interior. I unbolted it, put holes in it and the carpet, and mounted two more 6 1/2" speakers there. With the two right and two left speakers connected in parallel, I got my 300 watt capacity, and more volume than needed.
The head unit was my last purchase. Its a Kenwood KDC-7009 MASK CD Player / Changer control stereo, one of the best that Kenwood makes. The MASK option is cool, although in a convertible it doesn't offer the same anti-theft protection as a detachable face. It does, however, have an anti-theft code that is required to use the unit when power is disconnected. The reason I chose this unit was so that I could get a Kenwood CD-changer for the trunk, as it has CD-changer controls and a built-in CD player.
The whole system works very well. Bass is excellent (maybe a little excessive), the inside speakers produce enough volume to be heard at speed. The rear speaker idea works well too, with the top up. Unfortunately the rear view window drowns 'em with the top down, but they can still be heard.
You might get some vibration in the rear deck due to the high bass in the trunk. It's not that bad with the top up, and with the top down it goes away (for obvious reasons). This is only apparent with the bass settings very high. I'm still looking for a solution for this one, if anyone finds one let me know.
I put both amps in the trunk, along with the box. The larger stereo amp doesn't get that hot, so no cooling is really needed. The little monoblock gets VERY hot. I had to use two computer muffin fans attached to the amp to keep the heat under control. Both amps have a temperature circuit, so they won't catch fire if they get too hot. They just turn off.
And as for cutting the rear deck, it was very tedious, and not for the faint of heart. I don't know of any negative side-effects of doing this, except for feeling bad for mutilating your Miata.
Well, I hope this helps somebody. If you need more info (model numbers, prices, etc) just ask.
Glenn Price
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