NB Miata rear fill speakers

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NB Miata rear fill speakers

  • I am considering adding some rear fill speakers to the aftermarket stereo in my 2001 Miata LS. The most likely location I would use is in the base of the windblocker which would accommodate a 3.5 inch speaker or perhaps a 4 inch. My Kenwood Excelon receiver currently does not have anything hooked up to it. The onboard amp in the headunit will adequately power them.

       Has anyone done anything like this? Recommendations?

       And for the curious, I have looked at the postings in the Audio section at the Miata.Net forum.......  

  • The vehicle research we have on file for your '01 Miata doesn't list any options for adding rear speakers, so this would have to be more of a custom installation and you may have better luck going through a local installation specialist in your area if you don't experience with that work in the past.

    With that in mind, if you're looking for a nice set of 3-1/2" speakers to work with your Kenwood head unit, I would recommend looking into these Infinity Reference X REF-3002cfx speakers that we have on sale right now: www.crutchfield.com/.../Infinity-Reference-X-REF-3002cfx.html

    Anyone else have any suggestions or tips?

  • I am comfortable dealing with the aspects of this one, I think. I am considering the Infinity Reference X REF-4002c or Polk's db401's. In the location being considered, a grille is probably a decent idea. I also probably need to allow for baffles on the back.    

  • 4" speakers will add a little to the mix, at least you'll get more audible vocals and highs in the car, especially with the top down. Not sure if you're adventurous enough to try to fit larger, but if not, be aware that 4" speakers will likely need to be high pass filtered to keep form distorting on lower frequencies. Many Excelon HU's had the ability to set the front and rear filters independently, hope yours has such ability too.

    And while you'll want to isolate the rear waves of the speaker from the front, a small baffle (especially foam) from my limited experience with them, kill the output of the lower mids on down. Also, if you happen to use larger drivers (I ran 6x9s with them once), then with a good seal the foam baffle gets sucked in and pushed out and become audible and annoying.

    I'd try to build a larger solid rear chamber for the speakers and not use small baffles, but that's me.

    Also, Polk speakers tend to be power hogs in order to sound good.

    I'd be tempted towards the infinity speakers more, but again, if possible, larger speakers still.

  •  Thanks for the discussion of some aspects I need to consider. The installation as I described it is something that can be fairly easily reversed by replacing the modified windblocker with a different one.

      There is a surface area in the top well that can possibly be used by drilling out an area and using it somewhat like the package shelf in a sedan. The area would have a slight to moderate risk to dampness. The size of speakers that could be mounted in that location would include 5.25 inch rounds or a 4"x 6" plate. This raises the level of complexity - but is still quite doable. A fairly shallow back depth is desirable.

    The head unit that is installed is a Kenwood KDC-X497, if that helps with finding out about sound shaping.

      I have done crazier installs than this - back in 1974 I mounted 6"x 9" speakers in the package shelf of my 1972 Opel 1900 2 door sedan instead of taking the easy way out and mounting 5.25" speakers in the factory supplied hole. Perhaps that is one for the young & dumb club......  

  • You haven't seen some of the stuff I did years ago in my early days of driving/car audio. LOL

    Doesn't appear that model has independently set crossovers for front and rear speakers, only the X997 of that era seems to have had that feature, unfortunately.

    I've not done much looking, as I don't have or know anyone with a Miata, but with just some quick searching, seems there may be a couple options for installing larger rear speakers, depending on how conformable you are with custom fabrication.  However, I'm sure you've seen both and others as well.



    Not really liking how the guy in the Youtube video used baffles and then merely wrapped them to look like a single large enclosure, but to each his own.

    And then this is more like what you are talking about (I think), which this guy was able to fit a pair of 5x7's.


  •   For this thread being a more complete search option in the future for other Miata peeps looking for speaker ideas - this is the link related to my original idea - www.miata.net/.../wbspeakers.html

      Also, Miata.net forum user movingshadow has owned a couple of different NA and NB series Miatas and has used both 5.25" and 6.5" speakers in the location that the guys mount the 5"x7" speakers in the Youtube video Weigel list last in the post above.

      Thanks to Weigel for continuing the discussion. I will be moving forward on this project this spring using either 5.25" or 5"x7" speakers.

  • Please, by all means, report back with your impressions on the install you do and if you don't mind, take some photos or video of the install, I'm sure others interested in such would be appreciative to see a how-to, even if there's others on the net.

  •  Well, here we are 11 months later and I need to update this thread. I did end up installing speakers in the package shelf last spring. After considering again what I was looking for, I wanted as much low end in what I could install in that location without spending a boatload of money. I ended up going with the Infinity 6832cf - it is a 5x7"/6x8" that is pretty efficient and is rated to get down to 49Hz. I found that by measuring carefully a couple of different times a speaker of this size would fit above the shock tower tunnels with a bit of room to spare. The image attached shows one of the speakers in place as I am measuring to cut the top well carpet to fit around the speaker. This location fits just behind the windblocker.         

  • As you can see, I have used some Dynamat equivalent in the top well to reduce vehicle noise and located a set of grills for this set of speakers in this location. I prefer a bright forward sound, so the tweeter control is set at +3. Now the weak link in the audio system in this car is the sub in the trunk. I have located a fellow Miata owner that has designed a small box that sits in the front of the passenger footwell and uses an 8" shallow mount sub. That will be the upgrade I handle next.....    The attached image shows the speaker as it shows through the rear window. This is the one just behind the driver's seat. This sounds very good to my ears. I am satisfied my efforts on this project and would recommend this or something very similar for those that want a better audio experience. It is excellent with the top up, and still helps with rear fill with the top down, even though about a third of the backside of the speaker is covered by the top.

    [edited by: agp56 at 5:19 PM (GMT -5) on Tue, Jan 31 2017] added info.