Build your own discreet subwoofer that integrates into Honda Stock Sound Systems < £100

Any Vehicle Really!

  1. nauest
    Difficulty Level:
     
    Intermediate
    After popular demand I am going to give you a quick run through of a subwoofer project I built a while back but just integrated into my 7th Generation Accord. Not going to go into as much detail as my car guides, just the parts and basic method. I am happy to add more details on request. I will also try to get some more photos.

    The Sub itself is a 6 inch counter firing double active speaker. This means both speakers are powered and move against each other. This teamed with a very stable tubular enclosure give for a very punchy deep sound for a very small size. It adds a considerable range and additional clarity to the stock sub in the Accord Premium Sound system.

    I also think you should be able to integrate it into the non sub models using the method I used.

    DSC_0249.

    Parts

    These are the parts I used, however you could use your own arrangement.

    - 6 Inch x 150mm fan duct (From B & Q) (£15)
    - 2 x 6 inch subwoofer speakers, 4 ohms, make sure you get proper kevlar sub speakers with heavy magnets, normal 6.5 inch mid/bass speakers won't give you the power or speaker travel you need. ( £30 - £120 )
    - 1 meter of M6 threaded rod, 8 x lock nuts and washers (£10)
    - Aluminium sheet or heatsink, mine was scrap
    - 2 x 40 watt 12v monoblock amplifiers (2 x £18) http://www.maplin.co.uk/p/40w-power-amplifier-module-n67aw
    - A subwoofer filter/Preamp (£13)
    - 2 x old RCA Cable, or cheap stuff from eBay all male to male
    - a 10 k ohm resistor
    - Some speaker wire

    Other Bits:

    - Heat shrink
    - Solder and soldering iron
    - Hot glue
    - Electrical tape
    - Drill
    - Mini Screwdriver
    - 12v project wire


    1. Build Enclosure

    First attach 40 cm or so of speaker wires to the terminals of the two speakers, make sure that you get the polarities right.

    Drill 2 small holes in the duck so that you can just about fit the speaker wire through.

    then place the speakers into the ends of the ducting and use the threaded rod to clamp it down onto the duck. Don't do it too tight or it will warp the duct.

    Seal the enclosure. This needs to be done incredibly thoroughly, I used a mixture of silicone and hot glue to seal it, there mustn't be even the smallest leak as this is such a high pressure design, unlike a normal sub.

    DSC_0240 (1).

    2. Wire Amplifier

    The two amplifier chips need to be mounted onto the aluminium sheet to provide cooling.

    You then wire the two speaker wires into the corresponding holes in the two amplifier blocks.

    Wire in the 12v power wire to the two amp blocks and the preamp module in parallel. You can then either leave the other end of the wire bare to wire into your cars 12v system somewhere, or do what I did and add a laptop style plug and a 12v cigarette socket adapter.


    The signal side of the amp needs close attention. Cut open one of the RCA wires and put the outer copper wire into the negative terminal and the thin inner wire into the IN part of the amp modules.

    You will have one single RCA wire from each module, then you can plug each one into the OUTPUT side of the preamp filter module.

    Once you have done that you can make the adapter wire to get the signal from the in built speakers to the SUB.

    This wire is simply an adaption of one of your RCA cables. Simply cut both red and black open and extract the inner wires. Solder both of the inner wires to the 10 k resistor. Then solder the other end of the resistor to a thin wire. This wire can then be attached to one of the terminals of a speaker in your car, it can be any speaker but you will need to experiment with which terminal on the speaker to attach it to.

    There is no need to wire a negative signal wire as the negative will go through the power lead. I used the right hand terminal of the built in SUB for my source. Depending on which of the two terminals you use the new sub with run in or out of sync with your speakers. It will sound dull and poor bass if its out of sync, so try both and have a good listen.

    Wiring goes like this:

    Speaker - Amplifier Module - Sub Filter - RCA Lead - 10 k resistor - Car Speaker Terminal
    ^
    12v power

    DSC_1748.JPG

    You can use the screw settings on the sub filter to set a comfortable sub level (make sure the two volumes settings are on the same setting) Then use the bass setting on the car stereo to control it from the drivers seat from then onwards.

    I will put some more detail and pictures into this when I get time, please ask if you have any specific questions!