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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > AUDIO/VIDEO + BLUETOOTH + Electronics/Alarm/Software > Is it possible to run the rear speakers from the hi-fi amp or directly off the HU?



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      03-18-2014, 03:11 PM   #1
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Is it possible to run the rear speakers from the hi-fi amp or directly off the HU?

The JL G6600 my bro in law gave me is a monstrosity.
Since the space is taken up by a JL Slash 600/1v3 amp to power the sub...
And the fact that the JL XD600/6 is too expensive...
I was wondering if it would be possible to go the 4 channel route instead...

Had an offer for a Mosconi 120.4 which will fit where the factory amp is... Thinking of building a harness and opting for the CD-Changer boot wall trim. Seen it done on here before so bookmarked that thread.

Wondering if it is possible to leave the rear speakers running off the factory Hi-Fi amp or run the rear speakers directly off the HU?

To be honest the rear fill is crap anyway... but do have the odd passenger in the rear now and then.

This site says that the subs under the seats are driven off the HU anyway: http://www.audiofile-incar.co.uk/ind...d=46&Itemid=83 Not sure how true that is...
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      03-18-2014, 03:19 PM   #2
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If you have enough power for your front speakers you wont even notice they are gone. I started out with a center channel and rear speakers and I think it sounds better without them.
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      03-18-2014, 04:31 PM   #3
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yes the hifi hu is enough to power rear speakers for rear fill.
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      03-18-2014, 06:59 PM   #4
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Let's be clear, the HU output is a low-level balanced signal and cannot be used for direct connection to speakers. Only the output of the HiFi amp can drive speakers directly.
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      03-18-2014, 11:18 PM   #5
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sorry kai, that is simply not true. i have my rear speakers being driven from the hifi head unit directly. not loud mind you but plenty loud for rears.
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      03-19-2014, 01:10 AM   #6
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Quote:
Originally Posted by cdgatti View Post
sorry kai, that is simply not true. i have my rear speakers being driven from the hifi head unit directly. not loud mind you but plenty loud for rears.
Is that sufficient for the rear PDC?
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      03-19-2014, 01:23 AM   #7
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So it sounds like (no pun intended) there are a number of options...

1. Run the mosconi with harness... tbh this would be a PITA... don't fancy lifting and refitting that amount of trim.

2. Second and mostly likely option is a JL XD 500/3. Here my thoughts are... run the fronts and then use the rest to wire the subs in parallel off the third channel.

3. Wondering... if it would be possible to wire the fronts and rears in series... random thought and have not considered this in detail.

The XD500/3 is cheaper here and can be had for around 300... and the XD600/6 is anything from 400-500.

Was looking into importing from the states but customs charges would add up. Then thought about finding a retailer in the EU but the euro prices are higher than the UK ones!

Thank you all
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      03-19-2014, 07:50 AM   #8
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you'd lose a lot of output if you wired front and rear in series. if both sets are 4 ohm, you'd be at 8 ohm. you could wire them in parallel if your amp allows a 2 ohm load.
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      03-19-2014, 11:15 AM   #9
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Quote:
Originally Posted by cdgatti View Post
sorry kai, that is simply not true. i have my rear speakers being driven from the hifi head unit directly. not loud mind you but plenty loud for rears.
Of course you can connect the speakers, but it I believe it is generally not advisable to do so because the signal is intended to be used with a high impedance amplifier input. The speakers will demand more voltage and current than the signal can provide, and this may produce distortion and overdrive the HU circuitry.
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      03-19-2014, 12:41 PM   #10
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I have just the front and under seat speakers amped. When the volume is high I don't miss the rears but at normal volumes I really do miss having sound from the rear speakers. It's not that there is no sound from the rear, it's just that the front is just so much louder I can't hear them
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