[Vongolet]

Hello,

I've just installed a Blaupunkt THA 475 amp in my car along with two Earthquake SWS8Xi (2 Ohms) subwoofers.

My car has Hifi stereo originally and since the SWS8's are 2 Ohms I had to put them on the rear channel of the amp and then I have the PnP harness with the fronts connected to front channel, but to get the rear input to the subs I had to use the rear cable on the harness so now I'm left out with the output cable for rear speakers and no where to put it.

Sorry for the bad description.

So where should I now connect my rear speakers? Should I wire them up along the fronts output? Or on the input for the rear channel to let the original amp power the rear speakers? Is this even possible from the PnP harness?

http://www.blaupunkt.com/fileadmin/u...0001_EA_DK.pdf

http://www.earthquakesound.eu/car-au...s/sws-8xi.aspx

[ctuna]

If you have a 4 channel amp most would

only amp the front and underseats.

With a Hi fi to do it right you need a 6 channel amp if
you want the rear channels amped.

[Vongolet]

Originally Posted by ctuna

If you have a 4 channel amp most would

only amp the front and underseats.

With a Hi fi to do it right you need a 6 channel amp if
you want the rear channels amped.

This I do know, got the amp at a good deal though, the problem is that the PnP harness now leaves the rear speakers connection un amped in the boot.

[tlow98]

Originally Posted by Vongolet

This I do know, got the amp at a good deal though, the problem is that the PnP harness now leaves the rear speakers connection un amped in the boot.

I think that wiring them in parallel will effectively halve the power to your fronts/rears. This will negate the point of an amp.

I think you either have the front stage only with your current set up or buy a different amp if you want all 6 to play.

Doing anything else will likely result in the worst of all worlds.

[Vongolet]

But from what I've read the poem speakers are 2Ohm this means that if I wire the fronts in a series with the rear ones I should get 4Ohm out from the speakers which should be good

[ctuna]

Your math is correct but you loose stereo

[ctuna]

Your math is correct but you loose stereo
if you wire them in series. If you put them in parallel
the impedance goes down to 1 ohm and your amp won't
support that.

[tlow98]

Ahhhh.

Thanks, ctuna. Learned something here.

[Vongolet]

How do I loose stereo?

Would it be possible to wire the rear speakers on the input cables from the original headunit and amp? They are high level from what I can understand.

[ctuna]

If you wire the two underseats in series to one channel which is
common but not recamended when using a amplfirer with a single
sub woofer channel you loose stereo cause its one channel.
If you wire in parallel to the underseats to one channel the load
increases by 2 and the impedance decreases by 1/2 if you use speakers with the same rating.
Its difficult to tell what you are doing because your descriptions are
vague and inaccurate..


If you have the base system its common to leave the rear speakers on the head unit.
But you said you had the Hi Fi system so which is it?

BMW stereo types
http://www.e90post.com/forums/showthread.php?t=352586
http://www.e90post.com/forums/attach...2&d=1266451970
http://www.e90post.com/forums/attach...2&d=1260829447
http://www.e90post.com/forums/showthread.php?t=343673
http://www.e90post.com/forums/showthread.php?t=138949
http://www.e90post.com/forums/attach...1&d=1209780605
http://www.e90post.com/forums/attach...1&d=1209780865
http://www.e90post.com/forums/showthread.php?t=641323
http://bmwcoders.com/forum/3-er-8/bm...1-e92-e93-291/
http://technicpnp.com/menuDiagrams/d...e90_92_93.html
http://www.musicarnw.com/page-2/
http://www.e90post.com/forums/attach...4&d=1278871872

[Vongolet]

I have the HIFI system.
Do you have any experience of a PnP harness? Like the one I use from Blaupunkt? Would be easier to understand if you had.

But I tried to make a quick pic of how it is set up and my problem is that I now have the rear speakers wire in the trunk from the harness not connected to anything.

Blue color is front speaker output from Headunit -> Thru THA amp -> Front speakers.

Orange color is rear speaker output from Headunit -> Thru THA amp -> Under seat subs (2 Ohm SWS8Xi) in series.

[ctuna]

f you have a 4 channel amp and you might as well
run the underseats in stereo . one channel to each speaker location.
if you are running one of the rear channels to the under seat and
not the other you are loosing stereo information to one side.
If you have Hi Fi you need 6 channels to run all locations
because the radio or idrive in a Hi Fi options 676 before
09 has 5 volt pre out signals for both front and back.
The amp has to be 2 ohm stable to run the swsxi in stereo if
it isn't you shouldn't have bought the xi version.

[Vongolet]

What I should or shouldn't have bought isn't what I'm asking I got all of this for a great deal, my question is what the best solution will be with the setup I'm having.

[ctuna]

Don't connect the rear speakers till you get another 2 channel
amp . Rear speakers do not contribute much to the overall sound.
Connect the under seats in stereo one channel per speaker.
Great deals often come with compromises .
A lot of the stereo purists here feel rear speaker are a waste of money.