[Noise From Subs]

I'm thinking you can start with some basic troubleshooting:

Disconnect the RCA's - Is the noise still there?

What "kind" of noise are you hearing? In other words, what does it sound like? High pitch, low pitch...

[89 Mustang, Speakers Advise]

pk, it sounds to me like it would be worth the time and effort to go through the whole system front to back and see what is really going on behind the scenes.

Any time I help out one of the local folks here at home, I start by taking a pencil and paper and sketch out a simple basic system diagram as the car sits. That way I can look at it objectively afterwards and figure out where to start improving. Heck, a couple of times I actually found wiring problems just while I was looking and writing (I like those, they are the easy fixes... LOL)

Anyhow, you might be surprised at what you find in there... bass blockers, wimpy wiring to the speakers... hard to say really.

Other than that, I'm with bigjoe on this one...

If you can afford it, amp all of the speakers. Then you know you've got control over everything

[Is It Possible]

..........

#1 factor..

Your idea of sq.

Hmmm... darn good point there...

[Is It Possible]

You bet! The biggest factor is in how you install/place/aim your speakers. Two-ways can sound phenomenal. My opinion of course...

is it possible to get a sq system with mb quart qsd 216 6.5 an tweet or do you really have to have a 3way system?