Instructables

Poor Man's Surround Sound

Here is how to create excellent surround sound without fancy decoders or expensive equipment.
As they say "necessity is the mother of invention". Without the money for a proper setup (they (The Man) overcharge us (consumers) in Australia) my dad and I got his old speakers and amp and wired up something that sound like the real deal.
This instructable requires some (not much) knowledge about wiring speakers (plugs and whatnot)
 
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Step 2: Arrangements and connections

Arrange the speakers as in the diagram. Then use your wire to arrange the positive and negative connections as shown in the diagram. As I said this requires previous knowledge of speakers.

Step 3: Mount!

After you have hooked everything up you have to decide if you want to mount the speakers. I put the car speakers in the roof and the main ones on the wall. If you can't decide there are plenty of 'ibles on the subject, look around.
abadfart3 years ago
http://kantack.com/surround/surround2.html
 This is pretty cool, but I noticed on a few songs, parts of it, such as the guitar or drums, were really quiet or missing. Any way to fix that?
No, sorry, but it might be where your sitting in relation to the speakers. Some tracks have only the guitar or drums coming out of one set of speakers. Other than that I don't know.
 I found out what it was. One of the terminals on the back of my stereo broke off inside. Its really old. This setup works really nice with my new receiver though. Thanks for the instructable.
bowmaster4 years ago
This is actually called stereo quad. It sounds better then standard stereo or maybe even 2.1 surround, but it isn't as good as 5.1 or 7.1 surround.
 Wouldn't you need to run the negative on the bottom of the diagram back to the original? or if you connected the wire on one of the sides to a negative instead of a positive that would also work, otherwise you just have 2 wires that go off and do nothing
 I just saw a new 'ible, and they way they describe it in step 3 makes sense, the back 2 speakers get any difference between the 2 speakers, if they left one gets more it esentially becomes the positive and since the other one has less it effectively becomes the negative allowing the electromagnet to fire

DonQuijote4 years ago
how come you connect the rear speakers at the positive leads of the front speakers alone?
That way you get the difference between the right and left channels only... this doesn't really work like surround sound. I guess that's why its named "poor man's surround sound".
ok, dumb question. i already figured that out, but i still don't get it why this is remotely called surround. by the way, is the difference between the two signals enough to produce any sound at all in the rear speakers? {although i am good at understanding electronics, signals and stuff, i posses no encyclopedic knowledge about it} what is the voltage peak to peak range of a somewhat reasonable audio signal to drive some speakers?
According to Dolby® the rear fill is the difference between the front channels, of course they use a delay circuit, but the idea to take the signal from the positive side of the front-channels is just up their alley. It requires a lot more to generate the center-channel!
Two main speakers go in your front. standard stereo.
Two more speakers go in back of you. 2+2 stereo. usually done by the R/L RR/RL outputs of the amplifier.
The trick is, instead of hooking them up to the RR/RL outputs, which merely gives you more speakers... by running the differential feed though the rears, you get a sort of reverse echo.
It's only really "surround" in the placement of the speakers.
The rest of the "poor man's surround" is creating your own faux center channel!
Tie the - channels together into a speaker with an appropriate ohm rating, and put it smack dab in front of you.

Oh, who am I kidding, of course someone else has explained it much better than I could ever hope. http://electronics.howstuffworks.com/surround-sound7.htm

ohoh, I remembered something now.
It was called Quadraphonic Sound!

  • (LF+LB)+(LF-LB)=2LF or Left Front
  • (LF+LB)-(LF-LB)=2LB or Left Back
  • (RF+RB)+(RF-RB)=2RF or Right Front
  • (RF+RB)-(RF-RB)=2RB or Right Back
What we are doing, in this set-up instead, is muxing both side channels into one(LF+LB=Left, and RF+RB=Right) aka Stereo, then

  • Left(+)+Left(-)=Left Front
  • Right(+)+Right(-)=Right Front
  • {Left(+)-Right(+)} + {Right(+)-Left(+)} = Left Rear + Right Rear
What this does is, gives us normal stereo operation up front.
For quadrophonic, we'd need more signals, like a true surround,
but what we get from the "rear channels" is a monaural unified rear channel coming from both sides. Think of it as the 3½.0 surround.

You COULD use a SINGLE rear speaker, to accomplish the same thing, but you'd have to use a speaker with an impedance of BOTH main speakers... so you don't cause harm to the amp.(we want that amp to be happy @8 ohm, not unhappy @6ohm)

In any case, Whatever sound is supposed to come from the front does. Whatever sound doesn't come from "front"(aka from both speakers) then gets played from the front AND the back. Since we humans have only two ears... our brains get a little fooled.. and we "hear" the "non-front" sounds as coming from behind us. And since our directional hearing from behind kinda sucks...our brain interprets for us, and the visual clues from the movie fill in our mental gaps. It's "all smoke and mirrors" like the old saying goes, but it's particularly cheap and effective smoke and mirrors. And if you don't have the cash for a 5.1 or higher system, it does a bang up job of one-upping a standard stereo set-up.

I don't have specific numbers for you... but I can tell you, while watching starwars on laserdisc with a setup like this... you don't know where the tie fighter comes from, but it definitely feels like it comes from behind left, and zooms to in front right.

My amplifier actually does have 4 speaker terminals...but they're 2 pairs of stereo outputs.
So, I use the mains to drive to front speakers...
Then from the other terminals, I use the -R-L to drive a rear speaker, and the +R+L to drive a "center channel" speaker.

Sorry to think so disjointedly, but one thing to note.
This fake surround set-up does put double the stress on your amplifier.
Basically, what the practical side of this is is...well, if you only have to turn the stereo up to 20% for a nice loud movie, you'll be fine.
If you need to turn your stereo setup over 50%... THEN THIS IS NOT THE SET-UP FOR YOU. A stereo setup driving at 51%, converted to a poorman's surround at the same volume, will be demanding 102% from your amplifier.
and we shouldn't even be asking 90% of it for more than brief bursts. That's just bad karma.
super moderator (author)  ironsmiter4 years ago
Thanks for that. I think I understood most of it...... ;) Don't worry I never turn my amp up too high.
super moderator (author)  DonQuijote4 years ago
This does actually work really well. You do need your dvd/vcr/pvr/pc etc in surround sound mode though but that shouldn't be a problem. I've heard door knocks in movies and thought they were real, I've had planes land behind me and music just blows your mind.
super moderator (author)  DonQuijote4 years ago
If you wired it normally you would not get surround sound. This wiring converts the signal into surround (I,m not sure exactly how though)
n1qaw4 years ago
In the early days of car stereos I used to use this circuit to utilize the center speaker that used to come with the cars (really dating myself now) The only problem is that it can get a little over powering especially when the balance is a bit off. The cure is to install an L pad to raise the resistance of "center" array. Also if you disconnect the two mains you have a poor man's karaoke
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