Need 'stereo expander' circuitry for boombox

[7V]

Well not really a 'boombox', I'm attempting to build a classy portable stereo system to play MP3s, etc.

Both speakers will be fixed in the cabinet and non-detachable (for simplicity). Therefore they won't be as far apart as I would like. I am therefore looking for a circuit that can expand the stereo image so that the music appears to come from beyond the speakers.

Can anyone advise?
Also, should this be posted in another part of the forum? Things are getting complicated around here?

Regards
Steve

[dangus]

I've seen a circuit someplace. I think it just used an opamp to subtract a variable amount of each channel from the opposite one. Lout=Lin - (some fraction of)Rin. The pot could be wired to offer a range from full blend (mono) to normal to full wide (the blend range might be good for headphone listening). A quad op-amp wired as two inverting buffers feeding two inverting virtual-ground mixers.

Here you go:
Stereo Width Controllers
If the driving impedance is reasonably low, it should be OK to omit the non-inverting buffers and just use a quad opamp.

It's possible that someone like Rohm made a chip that did this. It was a fairly common feature for ghetto blasters, and might be found in some TVs.

Bass tends to be essentially mono, so making it wider will tend to reduce the bass in both channels. This might be a good time to consider biamping with a mono subwoofer. (Use a DVC sub so both sides of a T-amp can drive it.) Inserting a high-pass filter in the crossfeed signals should work... just a couple of series caps. Presumably the image information is mostly in the high frequencies.

[7V]

Thanks