With respect, I'm not sure the two replies you've received are any help.
Starr wrote some very helpful advice for ensuring your monitoring system has a good stereo image, which is separate from creating stereo space in your mix. And DarkRed's advice seems to be based on mic placement techniques and the quality of your outboard gear ... for the song you're creating completely in-the-box, entirely with virtual instruments. There's merit to what he's saying if you're making an audiophile recording of a live jazz performance, but it isn't relevant to your music.
I listened to all three of your example tracks, and your track as well. My thoughts:
Honestly, a big part of creating a song with a wide stereo feel is keeping the mix sparse. If you bury the song with piles and piles of instruments, it sounds crowded. A sparse mix has space. And most all of the popular stuff you'll hear these days is really sparse. For a lot of years, music was trending towards increased mix density, but now that's completely turned around.
Panning is also hugely important for space. The old rule for rock mixes of entirely mono sources is that "you better have a really good reason to pan something full left or full right." But that's changed, now that we have so many stereo instruments and so many stereo methods of processing. Don't be afraid to pan things 100% left and 100% right. (But do try to avoid every instrument panned to the extreme, or you end up with no "stereo image", just a generic wide sound. Some engineers call this the "big mono" effect, and it's not desirable.)
While arrangements are trending thinner, mixing is trending thicker. Try adding more voices for your synth lead or pad, for example. Or duplicate the synth lead, but make subtle changes to one of them: pan one hard left, the other hard right. Your brain will know they're different, though still identify it is the same instrument/same part of the song. This leads to a very wide sound.
Performance doubling is another way to achieve this. If you want your keys to sound thicker, particularly with digital keys, perform the keys part twice without quantizing. Hard pan the two performances. Again, your brain knows they are different yet thinks of them the same. It's very similar to double-tracking guitars, which has been the main source of width in rock mixes for ages.
You also can lean on widening/stereo plugins specifically to add this kind of effect. Some plugins make a mono sound appear as stereo. Take MicroShift by SoundToys for example: the original mono sound plays through in mono, but it adds a second copy of the sound slightly delayed, slightly pitched up, towards one side of the stereo image. And a second copy of the sound is delayed slightly more, pitched slightly down, and sent to the other side of the stereo image. If you don't abuse it (like 80's rock guitars and vocals), it can sound really cool and really wide. You can do this without MicroShift, but it's trickier to set up and dial in.
And other stereo image plugins can set how wide you want the mix to sound. 100% would be normal, 0% would be mono, but many of them can adjust to 200% width. I don't know what goes on inside the plugin, but it may help your mix, or certain instruments in your mix.
Modern mixing is very intricate and very delicate. We have the same basic tools we've already had, but how they are used, abused, layered, and flipped upside down is getting incredibly complex. I think it's fun. But it's not easy to learn. My best advice is to experiment.
But, if you want a wide mix, just a summary of the above:
- Keep your arrangement sparse
- Be willing to use absolute panning, according to the instrument
- Try out unison and other stereo features in your synths
- Try out double-tracking your instruments (even if they are virtual instruments)
- Try out goofy stereo tricks, or use a plugin like MicroShift that does this for you
- Try out stereo widening plugins
Share with us your progress.