More of a general production question I guess. What are some things you do to giving some stereo width to mono tracks?
I record all 8 tracks + stereo fx track separate at once into my daw. I like the single cycle wav basslines I can create in the Rytm - or using mono bass samples – but want to add some width to the mid/high’s without changing the sound dramatically. Same goes for hi/hat and upper range percussion instruments.
jamrod
2
One technique I use for this purpose is a stereo spreader - I use the built-in one in Logic but I’m sure there are others. Basically it pans different frequency ranges of a sound. For a bass, you could get some mid/high spread while leaving the fundamental intact.
Another great stereo-izer is a Haas delay, i.e., a hard panned copy of a track with a very short delay, like <40ms. Generally the original track is hard panned in the opposite direction, but you can play around with this. It makes it so the track sounds like it’s coming from the direction of the original sound, but gives a sense of stereo width that’s missing from standard panning of a mono sound.
A stereo chorus on a lot of sounds (including bass) can do this nicely too.
SImilarly, a stereo phaser/flanger on sounds like HH can give you width. I usually find this distracting on more important sounds, but YMMV.
Finally, mid/side processing on a mix that already has some stereo information can give you some control over the final stereo image. It’s worth reading up on, but essentially it gives you control over stereo elements of your mix separate from the mono information. So you can control stereo width, EQ separately, etc.
One thing to be very careful with wideners, is they they can badly mess up mono compatibility.
Especially some haas effect plugins, when in mono this can lead to horrible delay and phase effects.
I have found by far the most reliable way is to layers sound with wider material in the higher frequencies, fooling the brain into thinking the whole sound is wide.
There are reliable effects I have found, but again test in mono as some do not translate well.
The BX digital plugins work superbly, you can mono below a certain frequency and increase the side signal. In mono they have no negative effects either.
One of the best VSTs I have ever used is
http://www.brainworx-music.de/en/plugins/bx_digital_v2
None of this is a replacement for good layering and stereo placement imho.
There are myriad reasons why mono compatable sound is still very relevant in 2014, even on stereo club systems.
Forgot to mention BX digital’s ‘Stereo maker’ plugin as well, which is specifically for adding width to mono sounds, works better on some sounds than others and takes a bit of experimenting to get things right, but again in mono it causes no issues.
Not pimping the BX stuff, I just know it works without screwing things up when going through mono systems.
There are also some from PSP that work well. Most of the good ones have correlation meters on them too.
Have a look into Mid/Side EQ, it might be all you need to push and pull elements forward and back within your mix…
http://www.soundonsound.com/sos/mar11/articles/live-tech-0311.htm
Edit: Jamrod’s on the ball with Mid/Side already 
When I produced podcasts I learned a trick in Logic pro to get the feel of stereo with mono audio.
Use the Sample delay effect with just a small amount.
Here is a cool plugin that is free and do some great inter-aural delay tricks to widen stuff up. These delay tricks are also known as the haas effect as someone has mentioned already.
http://www.voxengo.com/product/stereotouch/
Another trick I like to use is some sort of auto panner set to go side to side by a modest amount.
One thing you need to be careful with though is phase cancellation with using delay tricks. Unless you don’t care about your mixes ever being heard in mono then it helps to check it in mono. There are some club systems that run in mono.
Also if the content already has some stereo information then you can use a mid side EQ and boost the gain of the sides(the stereo information) and that will give the perception of more width as well.
edit ::ok sorry I said a lot of what people said already. That free plugin is good though I use it a lot.
