Reverb is a time-based effect; it takes an input signal and applies a wash of very short delays of varying complexities, depending on the specific algorithm and settings. Clearly, based on the popularity of reverb, the effect works very well for adding ambience, positioning a track in space, and adding depth.
However, in some cases, you might want the texture you get from reverb, but without the complexity or “washiness,” especially in dense songs. In these cases, try using a delay as an ambience reverb substitute. Start your experimentation with a delay time between 5 to 50 milliseconds — in other words, too short to be an audible “slapback” delay — and then adjust the delay level and feedback to create the depth of effect you’re looking for. Use a mono delay to keep things tight, or a stereo delay to spread the ambience out.
This effect will create a simple, “hard” reverb that will have a great presence and fit into a thick mix very well. You can further shape the ambience with filters, EQs, and so on. Give it a try, you might just find the best ‘verb for a given track is a delay!