At this point (5-21-01), this is my setup:

Headunit: Alpine CDA-7873
Doorspeakers: Polk DX3065 (6 1/2 woofer & seperate tweets)
Amplifer: Kenwood PS-150 (older amp 75x2 RMS)
Subwoofer: Infinity Baselink (10" w/ built in 200 RMS amp)

Location of all the the stuff:

Headunit fits perfectly in the factory location. The 6 1/2 woofer is located in the factory door location. The tweeters are surface mounted at the bottom of the A-pillar. The sub is located where the tool kit used to sit.

My experience:

With the top up or when the car stationary, this is one of my best setups out of all my cars. Everything is in balance and all the sounds are definite.

With the top down is a different story. The highs are bright, the sub lows are sufficient, but the mids are drasticly diminished. When I turn the volume up to where the mids are satisfactory, the tweeters are screaming in my ears. The sound is definitly not in balance.

I don't have an explaination on why this is happening. I do have a theory:

1) Since the sounds are coming from different planes, the sounds dimnishes at a different rate. The tweeters are pointed right at me, so the diminution rate once it gets to my ears is the least. The mids in the doors are pointed at my knees. The sound has nothing to resonate off of (unlike a roof) and that is why the diminution rate is the greatest.


My planned remedy:

I need to control the volume of the tweeters seperately from the woofer. So I plan to use another amp (US Accostic USX-2050) to run the tweeters seperately from the woofers. I will use the front RCA for the tweeter, the rear RCA for the woofer, and keep the sub RCA for the subwoofer. I will crossover the tweets using the HP crossover on the amp at 4,600 Hz (12db/octave), almost matching the passive crossover that came with the unit. I will use my Kenwood to power my woofers and use the existing passive crossover. The sub is selfed powered. Now I can use my fader to lower the power to my tweeters and balance my sound between them.



I also considering returning the Infinity Baselink sub and getting the JL Audio Stealthbox. I'm not sure if it will sound better, but I will have more spacee in my trunk. Unfortunately, I will have to mount another amp.

 

[QUOTE]Originally posted by psycholist
[B]Since the sounds are coming from different planes, the sounds dimnishes at a different rate.

 

Sounds like a good argument for a programmable equalizer that would let you have "pre-sets" for different conditions.
Or some really interesting additions to the circuit S2Kman and almilli were looking at. Though their thing was purely for Sony head units.

 

Your planned remedy sounds good, but there might be an easier solution you may have not considered....on the Crutchfield website, I read about your speakers, and it referred to 12 setting for the tweeter level/woofer level, etc. There's probably an adjustment on the crossover...have you fooled with this at all? It may require a compromise, because it probably is not adjustable on the fly, like when you open the roof. Most likely the crossovers are in the doors, where you cant get to them easily. Aside from that, your plan with the two amps should work, but I'd try this first, it won't be as good, but won't be nearly as complicated and space-consuming either. Sorry if you already did all this, and I'm repeating info you already know