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      09-25-2011, 09:03 AM   #1
cdgatti
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Drives: e90 328i
Join Date: May 2011
Location: KY

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A budget 5.2 surround system

Thought that title might get some attention! OK maybe not a true 5.2 surround system but I have modified a hifi system to provide a center channel, surround sound, and right and left front channels and underseat subs all from a 4 channel amp. And it sounds really good, at least better than when I had just the fronts/underseats powered from the same amp. I get nice ambient effects in the music that makes the interior of the car sound bigger without detracting from the front stage, it actually lifts the front stage. It probably doesn't sound as good as an ms-8, but I have never heard one of those systems. There is no time alignment in this sytem. I've attached some pictures below

The system is hifi system feeding an alpine 4 channel, 75WX4, via a technic harness. Channels 1 and 2 from the amp feed a Dynaco QD-1 which is a fully analog surround sound processor from the '70's! It is basically the ancestor of modern Dolby surround sound. It is an amazing device that takes standard 2 channel stereo and outputs the stereo L/R for the fronts, an attenuated (in both volume and frequency) difference signal (L minus R) surround sound for the rear speakers and a common (where L=R information) signal for the center channel. I got it for $10! It is made up of standard electrical components, doesn't need any power and does not add any artificial digital effects. It also adds zero noise to the system, at least as far as I can detect. Channels 3 and 4 from the amp feed the underseat woofers in a conventional manner. The 75 watts X 2 for the fronts/center and surround are plenty for me, as the center/surround channels don't play as loud as the front L/R.

Here's a summary of the system:

Amp: alpine mrp 300
SP: Dynaco QD-1
Front speakers: BSW mids, Polk DB tweeters
Center: Polk DB 401 coax
Rears: BSW mids and tweeters
Underseats: stock hifi 8"

The amp is too big to lay flat in the stock amp location, so I mounted vertically and had to cut out some of the trim, so it is exposed, not happy about that and will look into seeing if the cd changer trim can conceal this for me.
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