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[email protected] mdindestin@gmail.com is offline
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Default Help an old school guy out with a sub

On Feb 23, 2:46*am, "MOSFET" wrote:
Well, the very easiest way would to do what you suggest and connect the RCA
outputs of your HU to your amp that will drive the subwoofer.

There is a very cheap and easy way to block the bass from your four existing
speakers (something you will most DEFINTAELY want to do as it will add
substantially more volume to your system, bass consumes the most power and
taxes small woofers the most). *Check out this site for a diagram and
explanation of how a passive
crossover would work.http://www.the12volt.com/caraudio/cross.asp

In a nutshell, you will connect a capacitor in line to the positive
connection of each of your four speakers. *Capacitors are cheap and you can
pick four up at Radio Shack for about a buck a piece. *This will give you a
6 dB per octive crossover. *This is not a terribly sharp crossover so I
would suggest a capacitor value of 200uF (200 micro-farads) to 100uF. *The
200uF will start the attenuation (crossover) at about 200 Hz (easy to
remember). *The 100uF will begin the attenuation at about 400 Hz (much
higher and will cut more low bass out and will allow you to play your
speakers louder). *Capacitors are so cheap you may even want to experiment
with a couple different values. *I have used this type of crossover many,
MANY times in the past for myself and other installations and they work
GREAT. *They are easy to install (only one wire has to be cut for each
speaker) and they just twist right onto the copper wire, then just cover the
whole thing with electrical tape and you're done.

Now, as far as a subwoofer volume control, there are many options for this.
PERHAPS (and this is a big perhaps) the RCA output level can be controlled
indepentally from the other four speakers. *My strong guess, however, is
probablly not. *The easist is to buy an amplifier that has an outboard level
control. *They are usually connected via phone cords and consist of a simple
volume knob you will have to mount somewhere near the dash. *This would be
your best bet. *Trust me, you ARE going to want to be able to control your
subwoofer output on the fly, perhaps from song to song as bass varies
dramtically in music. *If your amp DOES NOT have a remote volume knob you
can actually make one using a simple potentiometer (pot) connected between
the RCA outputs on your HU to the subwoofer amp. *The pot again will have to
be mounted somewhere you have access to you and it is just a volume knob
with three connections on it (I will not go into what all three do).

If you want to amp your four other speakers as well, I would STRONLY
encourage you to use two amps or a four channel amp (two channels bridged to
one channel for the sub, two channels for the four speakers, you can bridge
two speakers to one connection). *But this way you will lose fader controls
(you would connect right front and rear to one channel, and left front and
rear to the other). *If fader is important, you will probably need yet
another amp. *But there's a way around this issue. *Keep in mind that your
front speakers are the MOST important. *Like at a concert, music should come
from the front. *Your rear speakers should only give you some "rear-fill" or
some ambience as a natural room would when sound bounces off the back wall.
Therefore, 20 watts IMHO is plenty for your "rear-fill". *If you intend to
amplify the four cabin speakers, start first with the two fronts only and
see how you like that letting the HU power the rears (you will have fader as
you will be able to raise or lower the rear-speaker volume). *Again, once
the passive crossovers are installed and your front four speakers no longer
have to play low bass, your front four speakers will be dramtically louder.