To make a mix sound 3D, use level faders and panning to bring a signal closer or farther away, and to the left and right. Reverb can make a signal sound closer or farther away depending on the settings, and binaural processing is needed to emulate varying elevations.
Basics of 3D Mix
For this video, I want to show how to actually make it sound like a sound source is coming from a specific 3D location.
Starting with the basics, let’s consider traditional panning and level faders. Our left/right panpot is going to locate a signal to either the left or the right, while the level fader brings the sound closer with a higher level, or farther away with a lower level.
Let’s take a quick listen, and notice how the signal can be placed forward and back, and left and right.
Also, for the rest of the video, know that these effects work best when contrasted by opposing effects. For example, sending a signal backward by lowering a fader works better when contrasted with a louder, more upfront signal.
Psychoacoustic Left and Right
If we want a more realistic left/right placement we can combine delay and EQ. With the stereo sample delay, we can delay the right channel to place the signal toward the left, and vice versa – this mimics how one of the listener’s ears is farther away from the sound source.
If we want to make this even more believable, we can attenuate the highs on the same side we introduced the delay. So if we want the sound to seem like it hits the left ear first, I’d delay the right channel and attenuate the right channel’s highs.
Mid/Side and 3D Mixing
Mid/Side can also play a helpful role with a 3D mix – amplifying the mid makes the sound feel closer to the listener while attenuating it makes it sound farther away. Amplifying the side expands the image to the left and right – which actually makes it sound closer as well.
Attenuating the side will make the sound more centered. As we briefly covered last chapter, amplifying high frequencies makes a signal sound closer – so if we want a centered and close sound, we can amplify the mid image’s high frequencies.
For a spread and closer sound, amplifying the side image’s high frequencies.
Let’s take a listen to these variations and let me know if it subtly changes the closeness of the signal as well as if it’s centered or more spread out.
Sending Sound Back with Reverb
Reverb creates a wider sound by varying the left and right signals, but more interestingly, it gives us more access to the front and back. A longer reverb, with centered reflections and an attenuated high-frequency range, will make a sound source sound far away.
By narrowing the reflections we emulate how a faraway source would hit the left and right ears almost simultaneously, and by dipping the highs, we mimic how lower energy high frequencies would get absorbed as it traveled a longer distance.
Let’s take a listen and notice how a reverb with these settings sounds far away.
Bringing Sound Forward with Reverb
Perhaps counterintuitively, reverb can make a signal sound closer, especially if it’s used in contrast with a signal reverberated with the last chapter’s settings. A shorter RT60, usually 50ms – 100ms works well, as does an accentuate high-frequency range, and a wider stereo spread – basically, everything is the opposite as last chapter.
Let’s listen to 2 signals, one reverberated with the last chapter’s settings and one with this chapter, and notice how the contrast between the 2, makes their effects more apparent.
Transients and Tone Placement
If we want to augment the effect of how high frequencies are lost over time, we can use this SplitEQ by Eventide to attenuate the transients and tone separately. The transients will decay more aggressively than the tone, so we can attenuate the transient’s highs a little more.
Or we can do the opposite and booth the transient highs a little more than the tone to make the sound seem closer.
Let’s give this a try and see if it makes a difference.
Creating Contrast with Exciter
Exciters add harmonics to the high-frequency range, making a signal brighter and seem closer – if we use an exciter on one signal but not another, that affected signal will sound closer than the other. We can combine this with reverb to enhance their effects.
Let’s take a listen and notice how the exciter, when combined with close reverb, augments the sound of it being closer.
Using Logic’s Binaural Plugin
So far we’ve been able to place a signal left and right, as well as forward and backward – what’s more challenging is placing a signal up and down. For that, we’ll need to introduce binaural processing.
Fortunately, there are a fair amount of free plugins that can do this. Starting with Logic’s stock binaural panning, we can use the tilt function to affect the perceived elevation.
Conveniently, we can also affect how far away a signal is and if it’s oriented to the left and right.
Let’s take a listen to the tilt function being introduced.
Using Dear VR Micro Plugin
If you’re not using Logic Pro, you can try this free VR Micro Plugin by Sennheiser to change the perceived elevation. With the Azimuth function, we can change the placement between front, right, back, and left, as well as widen the source, which should make it sound closer.
Room reflections also give you more control – when off the sound is closer, but we can use various surface types and room sizes to alter the perceived depth.
Let’s take a listen to the plugin.
Free Anaglyph Plugin
This last plugin is a lot more complex, but I’ll do my best to cover it briefly. With the graphic to the left, we can switch between the top of the listener’s head, and the back – when moving the orb, we’ll notice that the settings automatically adjust to correspond with the position.
We can also emulate the sound of a studio listening environment at the bottom, which is a separate set of processing from the binaural stage. In the binaural stage, we can change the algorithm used to process the sound, as well as alter the head’s circumference and introduce micro oscillations to increase the placement’s realism.
There’s a lot to cover here, most of which I definitely need to research more, so let’s just take a listen to it.
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