new headunit install

[Ericfg]

So it's time for a new h/u and I need some advice.
First; here's what I got now:
4x6 in dash
6.5 in front door panel
6.5 in rear seat panel
2 12" subs in back

The current h/u is one pre-amp out going to a dash EQ that balances
line-out (from one (stereo) channel to 2 channels) to a 2 channel amp
for the subs and a 4 channel amp for the 4 door speakers. (The dash
speakers are piggy-backed (don't know the technical term for it) with
the front door speaker channel).

What I'm thinking of doing now is replacing the h/u with another one
pre-amp out as is currently. My question is can I wire the 4x6 dash
speakers to the front, speaker level outputs of the h/u? I don't
neccessarily need SQ there, just presence. Can I do that and still use
the pre-amp out for the rest of the system?

Hope you can undestand my description.
Thanks,
Eric G.

[MOSFET]

"Ericfg" > wrote in message
oups.com...
> So it's time for a new h/u and I need some advice.
> First; here's what I got now:
> 4x6 in dash
> 6.5 in front door panel
> 6.5 in rear seat panel
> 2 12" subs in back
>
> The current h/u is one pre-amp out going to a dash EQ that balances
> line-out (from one (stereo) channel to 2 channels) to a 2 channel amp
> for the subs and a 4 channel amp for the 4 door speakers. (The dash
> speakers are piggy-backed (don't know the technical term for it) with
> the front door speaker channel).
>
> What I'm thinking of doing now is replacing the h/u with another one
> pre-amp out as is currently. My question is can I wire the 4x6 dash
> speakers to the front, speaker level outputs of the h/u? I don't
> neccessarily need SQ there, just presence. Can I do that and still use
> the pre-amp out for the rest of the system?
>
> Hope you can undestand my description.
> Thanks,
> Eric G.
>

With most headunits the answer is yes. You can run your line-level outs as
well as the speaker outs on the HU at the same time, no problem.

I would recommend that you run ONLY 6.5" midbass drivers in the front doors.
I assume the 6x4's have tweeters and it is not a good idea to have multiple
sets of tweeters up front when they are spaced far apart. This tends to
make your soundstage VERY diffused.

But I would DEFINATELY continue to run 6.5" midbass drivers in the front
doors as midbass upfront tends to be a problem for most systems. Perhaps
there's even a way to configure the X-overs so that the front door speakers
only handle the low midbass, and then have the 6x4's high-passed above that
point. That would likely produce the best SQ (I know, you said you didn't
care about SQ, I can't help giving advice anyway).

MOSFET

[Ericfg]

MOSFET wrote:
>
> With most headunits the answer is yes. You can run your line-level outs as
> well as the speaker outs on the HU at the same time, no problem.

Hi MOS. Thanks!
>
> I would recommend that you run ONLY 6.5" midbass drivers in the front doors.

As I recall (in my drunken, Friday night state) both 6.5 sets are
"high-passed".

> I assume the 6x4's have tweeters

Yeah. two-way. (or 3-way)

> and it is not a good idea to have multiple
> sets of tweeters up front when they are spaced far apart. This tends to
> make your soundstage VERY diffused.

The front door 6.5 (two-way MBQs) are very low in the door. Firing at
my ankles.

>
> But I would DEFINATELY continue to run 6.5" midbass drivers in the front
> doors as midbass upfront tends to be a problem for most systems. Perhaps
> there's even a way to configure the X-overs so that the front door speakers
> only handle the low midbass, and then have the 6x4's high-passed above that
> point.

The 4, door speakers are low level passed. I forget where the x-over
piont is... 200...500.. something like that. But all the way up 20k

> That would likely produce the best SQ (I know, you said you didn't
> care about SQ, I can't help giving advice anyway).

I *do* want SQ. In my little world I got 2 high SQ subs in the back
(Mmats/PPI), 4 HSQ mid range doors spkrs (MBQ/old RF) and then adding
just a touch of 1k (low level) in the dash for presence/imaging.


BTW, as an aside, how long can one expect a high quality amp to be
"high quality"? MY PPI and old RF are mid-80s vintage. Does that
stuff degrade with time (like my JVC h/u did)?
>
> MOSFET

[MOSFET]

I'm not sure you fully grasped what I was saying in my last post. Of course
your front 6.5" front door speakers are high-passed (so they don't handle
the very low bass that your 2 12" subs produce). What I was saying is that
you MIGHT want to consider ALSO putting low-pass filters on those speakers
as well (this is called a band-pass filter because sound is then produced
only in a narrow pass band). This way, those speakers (the 6.5" front door
speakers would only handle frequncies between, let's just say, 80Hz and
300Hz). At 300 Hz, your 6x4" speakers would play everything above that
point. This would essentially give you a three-way speaker system up front.
IMHO, this would produce THE BEST SQ, imaging, soundstage depth, and all
that.

Anytime you have different speakers up front trying to play the SAME
frequencies you run into trouble. Beyond problems invovling imaging and
soundstage depth, the more serious problems involve cancellation effects.
When two different kinds of speakers (6.5" vs. 6x4"), even if made by the
same manufacturer, try to play the same frequencies there WILL be
cancellation (and strange boosts) at certain frequencies. This can be
avoided by making sure that they do not have to play the same frequency
range.

That was what I was sugesting in my previous post.

MOSFET
"Ericfg" > wrote in message
oups.com...
>
> MOSFET wrote:
> >
> > With most headunits the answer is yes. You can run your line-level outs
as
> > well as the speaker outs on the HU at the same time, no problem.
>
> Hi MOS. Thanks!
> >
> > I would recommend that you run ONLY 6.5" midbass drivers in the front
doors.
>
> As I recall (in my drunken, Friday night state) both 6.5 sets are
> "high-passed".
>
> > I assume the 6x4's have tweeters
>
> Yeah. two-way. (or 3-way)
>
> > and it is not a good idea to have multiple
> > sets of tweeters up front when they are spaced far apart. This tends to
> > make your soundstage VERY diffused.
>
> The front door 6.5 (two-way MBQs) are very low in the door. Firing at
> my ankles.
>
> >
> > But I would DEFINATELY continue to run 6.5" midbass drivers in the front
> > doors as midbass upfront tends to be a problem for most systems.
Perhaps
> > there's even a way to configure the X-overs so that the front door
speakers
> > only handle the low midbass, and then have the 6x4's high-passed above
that
> > point.
>
> The 4, door speakers are low level passed. I forget where the x-over
> piont is... 200...500.. something like that. But all the way up 20k
>
> > That would likely produce the best SQ (I know, you said you didn't
> > care about SQ, I can't help giving advice anyway).
>
> I *do* want SQ. In my little world I got 2 high SQ subs in the back
> (Mmats/PPI), 4 HSQ mid range doors spkrs (MBQ/old RF) and then adding
> just a touch of 1k (low level) in the dash for presence/imaging.
>
>
> BTW, as an aside, how long can one expect a high quality amp to be
> "high quality"? MY PPI and old RF are mid-80s vintage. Does that
> stuff degrade with time (like my JVC h/u did)?
> >
> > MOSFET
>

[Ericfg]

MOSFET wrote:
> I'm not sure you fully grasped what I was saying in my last post.
I did misunderstand. Sorry.

> Of course
> your front 6.5" front door speakers are high-passed (so they don't handle
> the very low bass that your 2 12" subs produce). What I was saying is that
> you MIGHT want to consider ALSO putting low-pass filters on those speakers
> as well
I happen to have a PPI elec crossover (Sedona XO-3) that has a
"mid-out" option (and a "tweet-out"). Would that work?
Alternatively what is another option?

>
> Anytime you have different speakers up front trying to play the SAME
> frequencies you run into trouble. Beyond problems invovling imaging and
> soundstage depth, the more serious problems involve cancellation effects.
> When two different kinds of speakers (6.5" vs. 6x4"), even if made by the
> same manufacturer, try to play the same frequencies there WILL be
> cancellation (and strange boosts) at certain frequencies.
That would explaine some harshness in the mid/high level. Good thing
is I got a 10 band dash EQ to help.
Thanks again, I appreciate you effort here Mr. MOSFET. :)