Kyle Hagemann wrote:
> Question is this - the component package includes crossovers
> that don't easily lend themselves to an installation of this
> type - they're designed for having both drivers driven off the
> same input. So, to get separate power to the woofs and tweets,
> I'd either have to open up the crossovers and get creative, OR,
> feed the woofs full-range sound. Does anyone have experience
> with either of these options? My thoughts are that the woof
> might work well with full-range sound, even though they're
> one-way drivers; then again, high frequencies sent to a bass
> driver might cause distortion...
I'd put a coil in series with the woofer. This will give you a 6dB per
octave roll off at the desired frequency. You could also put the proper
value capacitor in parallel to the voice coil, after the crossover coil,
if you want a 12dB per octave roll off, but it probably isn't needed
since higher frequencies roll off to some degree naturally when you are
off axis from the woofer and the woofer probably doesn't go beyond 5 kHz
anyway.
Contact http://www.madisound.com for crossover coils. You will need to
tell them the impedance of the driver and the desired crossover point.
They should be able to tell you what value coil you need.
Any stereo in a Roadster involves a series of compromises. The cars
weren't built with sound in mind. What you end up with is a factor of
how many compromises you are willing to accept, how much money you are
willing to spend, and how much you are willing to change the car.
Expect your setup to result in a strange sound stage. Most of the music
and the voices will be coming from behind you, but cymbal crashes and
other high frequencies will be in front of you. You would get much
better results if you added a small midrange with the tweeter and built
your own crossovers. This would move most of the music in front of you,
with the low end behind you. You also may be unhappy mounting the
woofers on the thin back panels as they won't seal well and are likely
to vibrate. A sealed enclosure behind the seats would be much better.
Finally, there is no substitute for a subwoofer if you want full range
sound. I am NOT a rap fan, but most all types of music sound very thin
without adequate bottom end.
I'm currently using an 8" JBL subwoofer using the trunk as the
enclosure, two 6x9 woofers in boxes behind the seats, and modified Radio
Shack minimus speakers (older die cast aluminum) for mids and tweeters.
I kept my crossover point low between the woofers and mids, but the
sound is still far from ideal.
I started with just the Radio Shack speakers mounted on the kick panels
and the 6 x 9's with a crossover and an amp. I keptblowing the
mid-woofers, even though they were only being used as mids with
12dB/octave crossovers. I got tired of getting free replacements under
warranty, so I replaced them with much better quality drivers. The 6 x
9's give little bass below 100 Hz in small enclosures, so I added the 8"
sub and amp. I use an equalizer between the CD and main amp to smooth
out the sound. I use a portable CD player through the headphone jack as
the head unit. The car still has the stock radio in place.
Roadsters really need very efficient speakers that can handle power, and
some power to back them up (or less efficient speakers with LOTS of
power). Unless you only use a hard top, you will always be competing
with a lot of background noise. If your head unit is not using separate
amplifiers, be careful when the top is down. Low power amps will "clip"
at high volumes and you can burn out your speakers before you know it,
even though the speakers are rated at a higher power than the amp. I
use 50 watts RMS (per channel, plus a sub amp), and that's barely
adequate to hear the music with the top down.
I built my system years ago, I'd probably do things much differently
today. I'd use high quality 6" woofers (i.e. Morel) in place of the 6 x
9's and more powerful amps with electronic crossovers. I don't think
there is a good way of putting woofers in the doors, so you're kind of
stuck with them behind your head. I am very satisfied with the die cast
enclosures on the kick panels, however.
Jim Anable
Seattle
SRL 311 13571
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