how to make mixes wider at analog mastering4. Double tracking
This method is the technique number one when you need to get a super wide sound of guitars in pop and rock mixes or fat vocal harmonies. You should just record exactly the same instrument part and pan hard tracks to the right and left. Width of a mix is guaranteed for you, a song will jump out of monitors, but the side effect of this technique is weak mono compatibility. This technique can also be used in other directions: try to pan two takes which absolutely differ from each other in timbre. Generally speaking, keep experimenting!
5. Modulation plugins
Such effects as a chorus, a flanger and a phaser create audible “thickening” of the original sound through the use of a short time delay and phase modulations. They are capable of changing a narrow sound considerably by expanding it in width and bringing a noticeable movement between right and left channels. But be careful, along with that they greatly change the timbre of instruments what, for instance, in most cases will hardly be suited to drums.
how to make mixes wider at audio mixing and mastering services6. Delay and the Haas effect
Another common technique for widening at music mixing services online is the use of the Haas effect to turn some mono instruments into stereo. The effect is based on a particularity of human hearing which, as far as known, doesn’t distinguish the delay shorter than 30 ms. Copy the track with the instrument and pan both copies to the left and right to the max. Apply a time delay up to 30 ms (in some cases up to 40–60 ms) to one of the tracks. Such a short delay is not perceived by human ear as echo, and, as a result, we hear one but quite a wide sound. If you create AUX bus with delay plugin with a zero delay on one of the channels and 1–30 ms on another and blend such processing with the original mono sound, you may achieve some interesting results as well.

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