Surround Sound for Free (it Could Save Your Marriage!)





Introduction: Surround Sound for Free (it Could Save Your Marriage!)

If you've got four speakers and don't want to lash out on a new surround sound system (or 'er indoors refuses to have any more AV equipment in her living room!), try this Hafler circuit.

I first found this in Everyday Electronics in 1975 (thanks guys!), and have been using various systems (once in the car) ever since.

It's not a 7.1 system, but it will add hugely to your enjoyment of stereo - and especially to DVD film soundtracks. Plus it doesn't matter where you sit in the room - you always hear stereo.

Step 1: Warning

I have heard that this system can overload your amp.

I have been using this circuit on a range of hifi equipment for thirty years, and I've never had a problem. But continue at your own risk.

Step 2: Wiring

The diagram shows what you have to do.

Stick two new speakers in the corners of the room OPPOSITE your existing ones.

Identify the + outputs from the back of your amp (your existing speakers will already be connected to them).

Now add an extra wire to each, without disconnecting the existing speakers, and connect those two wires to the + terminals of your two new speakers.

Now connect the two negative (-) terminals on your new speakers together.

Now wind up Guns n Roses - or whatever it is you like.

Hurrah! Instant surround sound!

Step 3: How It Works

The two extra speakers actually produce exactly the same sounds as each other. They play the difference between the original stereo speakers.

In other words, anything that is in the middle of the stereo image is not reproduced by the extra speakers: this gives the impression of surround sound.

Try a DVD: the swoops and whooshes of an action film do actually sound as if they are moving around the room.


Respect to the great David Hafler who invented this system.

Happy listening.



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    Hmm.. intriguing. I wouldn't worry about it overloading your amp too much because even if the left channel is at full positive and the right channel at full negative, they are still connected by two speakers in series, so theoretically double the resistance. I know that's not quite how speakers work, but it's a decent approximation to show we're not doing anything nuts like connecting the outputs together with no load. My question is, surely if there is something on just one side channel, it will still come from both rear speakers so "water down" the stereo effect? I guess having it from front left, rear left and rear right will "average out" to sounding like rear left, which will provide more subjective "depth" than just front left. If I had my quad speakers I'd give it a try... but then I have 5.1 on my computer anyway :)


    Yes, you're right: anything that is in just one speaker will come out of both 'rear' speakers. In practice, actually, you don't notice that, because one 'rear' speaker is always further away from you than the other. So you tend to hear the front left and the 'rear' right. Maybe it's psychological? Anyway, if you have a stereo system, try this hookup for a few days. then try it without. I bet you'll have it reconnected within the hour! I only put in that stuff about overloading the amp to silence all those nice folk who like to come along and tell you how rubbish your 'ible is. Look what they did to my paella recipe! :-)

    in my setup rear speakers are very close to sitting, but still the sound seems to be coming from front location. No scientist here, but stereo seems expanded not reduced.

    I have done this, and absolutely awesome, beats 5.1 straight away , where center stage is always a problem, Now I am making 5.1 amp with digital haffler matrix (with option to by pass it )

    Somthing seems wrong here. By connecting the rear speakers to each other, wouldn't you end up crossing the Left an Right channels to all speakers? This happened to me once while I was connecting Stereo sound a 4 speaker setup similar to this.

    What I ended up doing was running 2 sets of wires to the rear, one from the Left channel and one from the Right. I'm no expert, so please correct me if I'm wrong.

    nothing is wrong here, the back speakers only play difference (which is also digitally done by Expanding stereo)

    Adding an L-Pad to this set up also allows for controlling the volume of two extra speakers. Helpful in balancing the overall effect. I've used this set up successfully since the early 70's.

    Could you elaborate on that a little? I'm using this setup and my rear speakers are quiet.
    Front are 8 ohms
    Rear are 4 ohms
    My receiver says "A , B : 8 ~ 16 (ohms)"

    See link for general principals.

    for an example of what one looks like

    I found mine at radio shack. Only usefull if rear speakers are louder than needed, cannot boost volume but can dampen it if rear speakers are too loud.


    I've always used the same impedance front and back. The back speakers are supposed to be quiet in comparison to the front ones, but any audio with a good - or wide - stereo image should give you the effect you're looking for.