I wonder about the wiring into the front speakers/tweeters. I know that the radio only has one set of front channel outputs. That means that the tweeters take a splice off the front speaker wires. (I also know that the tweeters have a built in hi-pass filter, not an in-line one).
1) How does is the proper resistance maintained within the system? If you put an extra set of speakers in parallel with the front speakers at the same resistance (I assume), then the effective resistance is halved as far as the head unit (or amp) sees things.
2) So how does the this not throw off all the system's equilibrium or how is it compensated for?
3) I want to keep the factory head unit (for cosmetic reasons) but want to go into a 4-CH amp and then back into my 100W Polk speakers (Ft. and Rr). How then can I also feed into the tweeters without throwing off the resistance balance to the amp? (and don't say get a 6-CH amp, plz...)
On Sat, 14 Aug 2004 15:29:05 -0500, "Mike Lloyd" wrote:
radio only has one set of front channel outputs. That means that the tweeters take a splice off the front speaker wires. (I also know that the tweeters have a built in hi-pass filter, not an in-line one).
2K2 WRX, the tweeter has a small crossover capacitor attached. The tweeter is in parallel with the front woofer, and the wiring is in the door (ie only one pair of wires enter the door).
put an extra set of speakers in parallel with the front speakers at the same resistance (I assume), then the effective resistance is halved as far as the head unit (or amp) sees things.
Modern electronics are generally happy driving anywhere from less than
2 ohms, to 16 ohms or so; the higher load impedance (Z, AC resistance) yields a reduced power output. Having a tweeter+capacitor in parallel with the woofer is a very common arrangement, and results in the system Z falling from ~8ohms at low frequencies, to ~4 ohms in the treble ranges (assuming 8 ohm speakers). No problem.
is it compensated for?
See above.
go into a 4-CH amp and then back into my 100W Polk speakers (Ft. and Rr). How then can I also feed into the tweeters without throwing off the resistance balance to the amp? (and don't say get a 6-CH amp, plz...)
There aren't any line level outputs available on the OEM head, I would just drive the Polks directly until you're ready to upgrade. FWIW, the OEM head isn't too bad once you connect it to decent speakers. If you decide to use the speaker-level inputs of your amplifier (if it even has them), just feed the door speakers directly from the amp output. Watch the wire colors; they're wacky. Best check is to connect a battery across the speaker wires. Whichever wire is positive when the woofer cone moves _out_ is the + wire. (This is quite important, BTW.) When you go to install the speakers, you will need to fabricate a spacer to keep the magnet assy from hitting the window when it is down. There's not much room. I was able to mount a 5.25 inch Infinity Kappa sub on a 1/2 inch thick spacer; had to grind down two screws on the bottom of the window, and trim some plastic from the inside of the door panel to make it fit, too. Anything much larger just isn't gonna work unless you're willing to sacrifice the door plastic. The OEM tweeter is horrible; ditch it in favor of something else, almost _anything_ is an upgrade. The Kappas come with a separate crossover that is driven directly, and has selectable outputs for the sub and tweeter. They sound marvelous. I have a second set I can sell you for cheap if you're interested. (Infinity Kappa 50.5cs . . . $125 NIB!) I can heartily recomend the Alpine head units, look for a 7892 or 7894 (plays .mp3s) on ebay. Crutchfield or your Subaru dealer will sell you a "pocket" to fill the remaining space when you go from the Subaru "double DIN" changer to the "single DIN" Alpine (or whatever you like). Contact me directly if you need more specific nfo.
ByeBye! S.
Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101
I appreciate the help. I figured it was a simple question of the head-unit being 2-ohm stable up front, but wasn't too sure. I guess I worded my question all too complicated for such a simple question, really.
I put some Polk speakers up front and already have the infinity 4" in the rear. I didn't touch the tweeters since it was a budget thing. The car was brand new (
want to go into a 4-CH amp and then back into my 100W Polk speakers (Ft. and Rr). How then can I also feed into the tweeters without throwing off the resistance balance to the amp? (and don't say get a 6-CH amp, plz...)
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