Car Audio Config. Help

[Robert Coats]

Looking to update my car system....

Want to run front speakers off the new head unit's built-in amp, then run rear channel line-level (RCA) cords to an external amp, which will then drive a dual-cone subwoofer. The idea is to use the fader control to adjust the sub's volume. (The head unit I am looking at does not provide a dedicated subwoofer output.)

Will this work? Do most modern head units allow for use of speaker outputs and line-level outputs to be active at the same time? Do the fader (and balance) controls work both speaker and line-levels, regardless of what is actually connected?

[willtel]

That should work. Does your amplifier have a crossover on it to send a select frequency range to the sub?

What model head unit and amp are you using? That should help us tell you an ideal config.

[Robert Coats]

Dug a bit and found it the head unit DOES support use of a sub on the rear line-out, although it does not permit the front-to-rear fader to work :-(



I think the external amp has a 2-position low-cut, not a "sub-allow"(?) flavor.

Head unit is this one: JVC KWR800BT

[greglepore]

You can set the gain on the sub amp to balance the system, just not "on the fly".

[RANDY P]

Look at the subwoofer amp.

Easiest solution:

If the AMP has a built in crossover feed it signals off the RCA connectors labeled REAR preamp out and make sure the Subwoofer xover on amp is set to ON. This will give you fade front / subwoofer. Deck stays full range, no crossover.

Option 2 is simply use the one built into the deck and see if it has a "fading" option. Some units (like Alpine) give you the option to have the subwoofer level operate with the fader. The term is "fixed output sub" or "non-fixed output"- if your deck describes that feature then you can fade the ub.

Frankly, it's easiest just to plug the whole thing together, and be somewhat conservative with the subwoofer while the bass on the deck is set to zero. When you add bass through the deck it will feed the sub up slightly...

Frankly, I like non fade and I set my units being somewhat conservative with the sub, then add bass on the deck to suit.

rjp

[RANDY P]

sub amp has LOW PASS. It has built in xover. Low pass means amp only plays low frequency.