Tutorials · Sound and Music · Chapter 2

Near and far

A torch with a place

1. Select torch_left. In its Audio Source, open Spatial and tick Positional. Max Distance brightens, and Blend, Rolloff and Min Distance appear under it.
2. Select stone and press F over the Viewport to see the whole crypt, then click torch_left in the Hierarchy again: the view stays, and its ring is drawn round the torch: Max Distance, 512 for now, with a small square grab on its right. Min Distance is 0, so it has no ring yet.
3. Drag that grab, the small square on the ring’s right, until Max Distance reads 192, or type 192 into it.
4. Set Rolloff to Linear.
5. Type 24 into Min Distance. A small ring appears round the flame, with its grab on its left: drag it to try other sizes, and leave it at 24.
6. Press Ctrl+S.

Positional

In the Spatial group: ticked, as a source comes, the sound is quieter the farther it is from where the room is heard, and leans to the ear on its side; unticked, it is the same everywhere, as chapter 1’s torch was. The rows from Max Distance to Min Distance are about how a placed sound is heard, and are dimmed or hidden when Positional is off; Pan works either way. A sound with a place is heard from the knight’s feet once he has an Audio Listener, below, and from the camera until then.

Max Distance

How far the source is heard, in world units: past it, silent. 192 is twelve cells: across the hall, and gone just past the well room’s door. A source past its reach still plays, at nothing, so walking back brings it back where it was in its loop. The large ring, with its grab on the right. A new source’s is 512.

Min Distance

How near the source is at its full Volume, in world units: inside it, nothing is taken off for distance. 24 is a cell and a half round the flame, so under the torch he hears it as loud as chapter 1’s. The small ring, with its grab on the left; at 0 it has no ring. A new source’s is 0.

Rolloff

How the sound fades between the two rings, measured as how far across the gap he is, from 0 at Min Distance to 1 at Max Distance. Quadratic, as a source comes: falls fast at first, then eases into silence with no edge at the large ring. Linear: the same amount lost every step, so it arrives at silence still falling, an edge you can hear, which suits a sound that must be gone at a known place, as this torch is past the well room’s door. Inverse: a real fire’s fall, most of it lost in the first steps away, then hanging on faintly, and brought down to nothing at the large ring. Logarithmic: the same number of decibels lost every step, from none at the small ring to 120 at the large one, which sounds like a thing going steadily away. Custom: a curve you draw.

Custom, and its curve

The Rolloff for a shape none of the other four give: choose it and a curve row appears under it, a small picture of the curve whose fold arrow opens it into a canvas, Min Distance at its left end and Max Distance at its right. The sound’s level at each distance is the curve’s height there, from 0 to 1. Double-click the line to add a point, drag a point to shape it, and right-click it to remove it. Until it has a point, the source falls as Quadratic does. No sound in the crypt needs one; chapter 12’s gallery has a bell that carries far, and draws its curve there.

A second fire

1. Select torch_right, press Add component and choose AudioSourceComponent.
2. Set Clip to torch.wav, Volume to 0.6 and Pitch to 1.1, and tick Looping and Autoplay. Leave Bus on Sfx and Positional ticked.
3. Set Max Distance to 192, Rolloff to Inverse and Min Distance to 8, the size of its flame.
4. Press Ctrl+S.

The dripping well

1. In Assets, click drip.wav in audio, set its Stream to Never in Details and press Save, as chapter 1 did for the crackle: it is five seconds, and plays all the while.
2. Select well in well_room, press Add component and choose AudioSourceComponent.
3. Set Clip to drip.wav, Volume to 0.8, and tick Looping and Autoplay.
4. Set Max Distance to 320, Rolloff to Logarithmic and Min Distance to 16, a cell round the well.
5. Press Ctrl+S.

Ears for the knight

1. Select knight, press Add component and choose AudioListenerComponent. Its one field, Enabled, comes ticked.
2. Press Ctrl+S.

The Audio Listener’s Enabled

Whether the crypt is heard from this node. Ticked, as it comes, every placed sound is measured from the knight’s feet and panned by his side. Unticked, or with no Audio Listener at all, the camera hears instead. By the hall’s west wall the two differ: the confiner holds the camera at x 160, east of him, so without his Listener the left torch would be heard on his left when it is on his right.

Near and far, heard

1. Press F5 and click the Sound tab.
2. Walk east to the end of the hall, then down through the south door into the well room and to the well.
3. Press F5 again to stop.

Blend and Pan, tried and put back

Blend

How much of the source’s place is used, from 0, none, to 1, all, as it comes. At 0.5 half the sound is placed and half is heard the same everywhere, past Max Distance too. Try it: set the well’s Blend to 0.5 and walk to the bridge’s east bank, past its reach. The drip is still heard, about 6 dB under its Volume; at 1 there is nothing there. Set it back to 1. Chapter 12’s bell uses a Blend under 1, so a tenth of its toll is heard in every room.

Pan

A lean added to the side the sound is heard from, from -1, all left, to 1, all right; 0, as it comes, adds none. The place gives its own lean: how far to his side the source is, against its Max Distance. Try it: set torch_left’s Pan to -0.75 and stand right under it, where its place gives it no side. It is heard on the left, by more than 3 dB. Set it back to 0. Chapter 4’s doors use a Pan of their own, for a recording that leans.

Near and far

Check it works