Dolby Atmos is a Rendering format so source material might truly be anything you have available. Here are a few examples:
- If you are a songwriter and are looking to start writing music which will be consumed in Dolby Atmos you could have any instrument, sample library, VI etc as your source material.
- If you are a recording engineer you might have stems that have been previously defined by a writer or tracks captured live in studio or a multitude of other formats that can be used to create a Dolby Atmos sound field.
- If you deal with legacy recordings you might have anything from a mono tape to 48-track tape restore or other formats. All can and have been used to create a Dolby Atmos sound field. Some methods to do this have been re-amping those sources into a studio environment and capturing the output in room; separating sources out from the available tracks and repositioning them in the sound field and a variety of other source extraction methods.
However you get to the mixing stage of your Dolby Atmos project the choices you have are the same:
- Does this sound work best as part of a bed or as an object?
- If I apply temporal effects to this sound source should they follow with the object or exist in the bed?
- The fundamental principal is that if it sounds right then it is right.
Generally speaking, the greater variety of source material and the more atomic and separated it is, the more options and flexibility you will have when creating an Atmos mix.
As an example, if all of the drums and percussion instruments in your project are mixed into a single stem, you will only be able to create a single object or bed, which limits your creative choices for positioning in relation to your listener. If you had individual tracks for kick, snare, hit hat, chimes, cowbell etc. you could potentially position them in disparate parts of the room to create a sense of space.
More suggestions on preparing source content for Atmos mixing:
- Using mono stems, rather than stereo stems, will allow for more control of object position.
- Consider printing out a wide variety of tracks (With and without effects, mono, stereo, bussed etc.) and experimenting in your mix.
- Printing effects separately from the dry sound can allow you to place the dry source in a different position from the effects, and also allow you to apply different binaural render mode settings for the dry source and effects. This can be especially effective when working with vocals
- If only stereo stems or stems with effects included are available consider using mid/side processing and position the 'mid' and 'side' separately
- The binaural render mode settings apply a distance model to the objects for which they are selected. You may want to try these with source content free from other spatial effects (reverb, etc) to see how the settings change an object's sound.
- The renderer works at 48 and 96kHz. Using source material with sample rates at least this high will yield better results than material that is upsampled.