Closed Thread
Results 1 to 3 of 3

Reload Thread: HELP with very small subs in BMW Roadster

  1. #1
    roadster-dan's Avatar
    roadster-dan is offline Junior Member



    Join Date
    May 2002
    Location
    Minnesota
    Age
    37
    Posts
    2
    Post Thanks / Like
    Mentioned
    0 Post(s)

    HELP with very small subs in BMW Roadster

    I have a 2000 BMW ///M Roadster. The stereo in this car absolutely blows. You would think for a $42K car (bought it used for $31.9K) it would be decent - not a chance. It's flat, muddy, and has an amp with 10% THD (yes!, 10%). It has 10 Harmon Kardon speakers that make you not want to listen to the stereo:

    2 - 5 1/4" woofers in the kick panels
    2 - 2" mid-tweets in the door
    2 - 1" tweeters in the door
    2 - 4" mids behind the seat
    2 - 5 1/4" "subwoofers" at shoulder level between the seats

    I don't know how they get away with calling the two 40 watt farting/buzzing paper cones between the seats subs, but I guess that's thier business.

    I have already replace the 5 1/4" kick panel woofers and the 1" tweeters with Boston Acoustics ProSeries 6.5 components. I am very pleased with these! They sound great, even being driven by the crappy 10% THD Harmon Kardon amp. The next move is to replace the rear mid 4" drivers with Boston Pro 4" woofers. Since I can't seem to find 2" mid-tweets anywhere, I think I'll just leave the stock ones disconnected (unless somebody knows where to get some good 2" mid-tweets).

    The amp will probably be next. I haven't decided on that yet, but I am leaning towards Xtant (probably the A4004) unless somebody warns me away from them.

    Now that you know what is in the car, I need help with one piece - the crappy subs. Rule number 1 - no subs in the trunk. It's already tiny and I need what space it has. This leaves me with VERY limited options in the factory location. The trunk is sealed from the passenter compartment anyway, so any bass that makes it up there is probably quite muffled. The car next you would hear it better.

    Sub Option 1:

    The largest sub that I think I could fit (due to 3.5" mounting depth and 5.75" cutout limitations) is a Rockford Fosgate 6.5" sub in a custom box. I can make it so it has about .2 cubic feet of air space after the sub is installed. This is right within spec for the sub (.1 - .3). This is also an affordable option.

    Sub Option 2:

    Sunfire (yes, Bob Carver's Sunfire) developed a Subwoofer just for the BMW Z3 that drops into the factory location. It comes with it's own 400 watt amp. There are a few hitches though, it only works with the newer model HK stereo that was installed in Z3's about 2 months after mine was built. It requires balanced inputs (+, -, and a ground) and would be quite a trick to wire. It also has a proprietary 46 pin connector that's in the newer Z3's and I CAN'T get it from BMW. It's not a part they sell. I would have to take apart the Sunfire and solder in my own connections somehow. That It also costs around $550 - $700 depending on the BMW dealer you get it from. I think this is my last resort...

    So, back to Sub option 1. How do you think that little 6.5" sub would actually sound? SQ is more important that SQL to me. Does anybody know of a decent sub that would fit in that small space and sound good? The fosgate $75 sub sounds a little cheap and I'm concerned if it'll sound decent.

    Any suggestions?

    Here is a pic of my car




    2000 BMW ///M Roadster




  2. #2
    LoneRanger's Avatar
    LoneRanger is offline Old Yamahas Give Me Wood



    Join Date
    Dec 2001
    Location
    Wellston, Ohio
    Age
    32
    Posts
    1,379
    Post Thanks / Like
    Images
    10
    Mentioned
    0 Post(s)

    here's a few ideas

    Let me start out by saying that you own a very beautiful piece of equiptment there. I owned a BMW once (a salvage title 1990 325i turbo) and it was probably the fastest (0-60 in 6.2 seconds!) and most responsive vehicle I've ever owned.

    I know that a few companies make small bass drivers like you're looking for. JL Audio makes a 6" or 6.5" and so does Digital Designs. Both are great drivers (definatly superior to the Fosgate) and will fit the application of .1 to .3 that you mentioned.

    I've heard all three (Fosgate, JL, and DD). The Fosgate and JL are in the same price range, and even though the price difference between the JL and the DD is pretty substantial (The JL retails for about $85-$100 and the DD for about $150), they both sound very similar to me. The fosgate sounds okay, but it's not as punchy as the other two.

    The only problem with a small driver of this sort is the low end frequency response you would get with a 10" or 12" versus a 6-6.5" sub is compromised because of the small cone size. To put it simply, you're probably not going to hear anything below 60 hz with either of these subs, no matter how either company rates their product. But, depending on the music you listen to, you might not need that low end anyway.

    My suggestion to you would be to check out both drivers I mentioned before going with the Fosgate. Who knows......you might like the Fosgate better, but I'd almost guarantee you'll like one of those better.

    BTW....You might want to check out Cadence's Z6000 amp. It's a six channel amp with 75w x 6 RMS @ 4ohms, and the power doubles at 2 ohms. The THD is 0.044%, and you can run the channels in pairs so that some are 2 ohm and others are 4. This would probably run your entire system pretty efficiently, not to mention the Cadence amps look cool as hell!

    Hope I've helped you at least a little!



    "There is no 'I' in Tag Team"

    Project 'rex: Coming Soon to An Eardrum Near You

  3. #3
    roadster-dan's Avatar
    roadster-dan is offline Junior Member

    Threadstarter


    Join Date
    May 2002
    Location
    Minnesota
    Age
    37
    Posts
    2
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Thanks! That actually helps a lot, especially consiering you have heard them. I think I can make the JL work (3.5" mounting depth is VERY close) if I make the enclosure out of fiberglass instead of 1/2" MDFB.

    Personally, I'm not much of a fosgate fan. I hadn't managed to track down the fact that JL made a smaller one, so I am very happy about that. The main reason I was leaning toward the Sunfire possibiliy was that I didn't really want to use the fosgate sub. I know some people really like their stuff, I'm just not one of them.

    I find it interesting about the 60 Hz "cut off" point. I knew there would be a sacrifice with a small surface, but I wasn't sure how to measure it. Very cool to know. I think the smaller sub will give me the extra "punch" and tightness I'm looking for. If I decide I want more, I may look at something additional in the trunk to hit the really low frequencies.

    I'll definately look into the Cadence amps.

    If anybody has any other ideas, I'd love to hear them.



    2000 BMW ///M Roadster

Closed Thread

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may post attachments
  • You may edit your posts
1e2 Forum