I recently scored a Sears SR-2100 Series boombox from a garage sale for $2. It's in really great condition but sounds pretty bad. I tried "Stereo Wide" and yes, it gives a slight surround effect, but it is absolutely harsh and shitty. I'm wondering what is technically going on to achieve this effect?

Stereo wide is a basic signal processor, created to widen the perceived stereo sound-stage, to make it sound like the speakers are further apart than they are.

Stereo is Left channel & Right channel (L plus R)

A stereo wide system will take what only occurs in one channel (L minus R), put a delay on it & feed it to the other channel. So sounds from one channel are 'echoed' in the other channel making it sound like the source of the sound is further to the left or the right.

Stereo wide / Ambience, Surround, Biphonic, Spatial, etc. all do something similar to this, with varying levels of success. Personally I like Philips 'Spatial', as it's quite subtle, & I'm less impressed with Hitachi's Surround which alters the sound too much for me.

I see- thanks for the explanation!

The effect mostly depends on the quality of the source material.

As isolater42 explained, the quality of the source channel decides the output quality of the function.

Try it with different songs. You will find some songs are aweful, whereas some are nice!

Just a guess ....
Each channel is separated into frequency bands on the
assumption that individual sound sources in the stereo image are
somewhat pro-spectral distinctive. The stereo phase-shift of each
frequency band is measured, and the lagging channel of each is

delayed proportionately a little bit more. I presume there is a

single transformation that does the phase measurement and

scaling in one step, hence the switch.

If it isn't done quite correctly it may have a effect on the lower frequency.

I totally agree Isolator, out of all the stereo wide features I also think Philips got it just right