Boston Acoustics Rally RC620

[1/12/2002] Reviewed by: Carl McMillan - cmcmillan3@yahoo.com

Applicable to: '99 +

6.5" Component Speakers

Once the speakers were installed (a long process), they sound absolutely fantastic. I now have mid-range, mid bass, mid highs, and everything in between. The tweeters are adjustable and are smooth as silk! In fact, they are silk! I adjusted their volume down a bit. The tweeters have 3 settings: 0db -2db and -4db. I used the -4db setting. In addition to this, I added a 6.5" amplified Bazooka tube in the trunk to round out the bass. It's an OK compliment but, shows that the Boston's are real speakers whereas the Bazooka is so-so audio componentry.

I have the '01 LS with the Bose system. I tapped into the pre-amp outs and wired straight into an MTX 66 watt per channel amp. (It's a 6200 series 2-channel amp.) I had to create 2 'doughnuts' to downsize from the 8" cutout in the doors to the 6.5" size. I used something called 'hardboard' from Home Depot and a jigsaw to create these. I then used Dynamat inside the doors and around the wooden doughnuts. Also I added 6.75" speaker baffles to fit around the backs of the speakers to keep water off. I could have used the original plastic rings on the Bose speakers but, the Bose had water in them when I removed them... So, I figured they weren't very effective. And, at $200 a pair (from ebay), I didn't want to take chances. This is a somewhat difficult install due to the amount of customization... especially if you have not done much car stereo installation work.

Over 30 minutes to remove completely


Boston Acoustics RX67

Reviewed by: Toby Weir-Jones

6.5" coaxial 2-way speaker system. I paid $134 + tax for the pair.

This is my third set of Boston car speakers, in as many different cars. I considered getting the Rally component speakers, but shied away because I didn't want to worry about flush-mounting the separate tweeters. My car ('96 Leather pkg, no MPSS) didn't have factory tweeters anyway.

The install went smoothly enough. Remove the screw hiding behind the door lock slider, lift up the door handle and slide the plastic moulding out. Then pop out the plastic cap from the top end of the arm rest and remove the screw you find behind it. Also remove the two screws on the undreside of the arm rest; they are shorter than the upper one so make sure you remember this when it comes time to reassemble.

If you have manual windows you'll also need to get the crank handle off. There is a retaining spring clip that needs to be removed before the handle will come loose; check other documents on miata.net for details, as I've never had to do this.

The door panel literally pops off; there are a number of pressure fittings that hold it on, so just wiggle your fingers under the edge of the door panel and pull gently until they come out. There are a few in the middle regions of the panel (i.e. not just along the edges) which you also need to remove.

Once they're all done, just lift the panel up from the top edge of the door. The factory speaker will be sitting there exposed, and held in by three screws. Remove each of them and the speaker will come free into your hands. There is a wiring harness that connects the factory wiring to the original speaker; just squeeze down the top tab and it will come out.

I found that I had to remove the three white plastic screw-mounting points from the factory speaker in order to get the new speaker into the door. I used square-edged pliers to grip them and pull them out without any trouble.

Before you do anything else, you should weatherproof the new speakers. I've always just wrapped the surrounds in duct tape to keep moisture out, though others will recommend you buy special speaker baffles for a better result. YMMV.

The biggest problem I had was figuring out the polarity of the factory wiring as it entered the harness. The wires are not helpfully-coloured; one is red with a yellow stripe, the other is red with a green stripe. Since I had already installed my in-dash unit, I could no longer see the wiring harness in the dash in order to work out which was which. If you ask Crutchfield nicely they might give you a final answer to this question, but in the end I've got one wired one way, and the other wired the opposite. Once I've had a few days to listen I will decide which one is wrong and go and reverse the connections.

Anyway, assuming you can figure this out in a more scientific way than I did, you just need to wire up the new speakers, bolt them to the doors, and put the door panel back on. I had to use the speed clips provided with the speakers in order to get usable mounting points, and start each of the three screws just a little bit so that all three would bite.

One other note: if, upon removing the door panel, you find that some of the plastic pressure clips stay in the door instead of the panel, you can remove them using wire cutters. Just close the jaws of the cutters gently (not all the way!) and lift; the pin will just pop out, and you can re-attach it to the appropriate door location.

Anyway, now that the upgrade is done, the sound quality is much better; even more so since I also removed the capacitors from the factory headrest speakers. I'm fairly sure the driver's door is the one I got backwards but it's been less than a day.

Feel free to contact me with questions or a need for clarification. Good luck!


Boston Acoustics RX67

Reviewed by: Michael Taylor - taylormw@ibm.net

This is a coaxial 6.5" speaker that replaces the factory Miata door speaker with no modification to the door panel or sheet metal. Frequency response is 55-20KHz; sensitivity 95db. Retail is about $150.

I chose this speaker because of it's slightly bright sound which is ideal for top down driving. This speaker is slightly larger than the factory speaker, so the screw holes didn't match up exactly. To solve this problem I had to pop out the existing plastic grommets that serve as anchors for the factory screws, leaving a larger hole to work with. The speakers come with "U" clips which can be slipped over the holes giving some room for adjustment. The Boston Acoustics didn't come with rain baffles, so I removed the baffles from the factory speakers and trimmed them to fit the new speakers. The tweeter doesn't protude too much, so the speaker will fit under the factory grille.

Impression? The new speakers are an incredible improvement over the factory units. With the high sensitivity, they play much louder and actually drown out the factory headrest speakers with the fader at center. With the top down, highs and vocals are very clear. Before, I found myself setting the treble at max with the top down, but now it sounds fine at the flat setting. Bass is much tighter and controlled. Definitely a good investment!


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