UE4 Soul City Audio Implementation Final
Occlusion by Ray-casting
Ray-casting Occlusion System has been made in Blueprint to create realistic behavior of ambient sound of rain and wind. It was a tricky one as single objects can attenuate sound while all it should do is to attenuate outdoor sounds while the player is in the inside building. It was necessary to edit collision properties of visible and invisible objects (like Blocking Volumes). Occlusion by ray-casting is very effective in a situation where the player can open/close doors in a closed space. It will automatically attenuate outdoor sound by following a filter/volume curve which in this example was made for 3 different surfaces from 0 to 20kHz and one for volume attenuation: 0 to 1.
The occlusion system analyzes the distance between player and audio source check for objects between them and automatically apply filter and volume curves.
Quite simple yet effective alteration fo the sound by the change of pitch while player press key assigned to Slow Motion / Matrix-alike effect which is slowing time.
Player Weapon Projectile:
The player weapon is not a gun but a projectile of the energy ball. Few questions I've had to ask myself: - How to distinguish the sound from a similar kind of enemy weapon - How to avoid repetitiveness as it's sound that player will hear frequently during the whole game. The answer to the first question was: sound of ice because the enemy uses fireball. For that purpose, I recorded the sound of scratching ice in the fridge. It was processed with Spectral Delay, a very rare type of effect. Also, it was parallel processed with another type of rare delay effect. That way looped audio was created for the projectile.
To synchronize initialization of projectile shooting separate audio cue was created which plays only once at the beginning of the animation. Here comes the answer to the second question. The audio cue was split into two parts which 4 alterations each which gives 16 different combinations. Audio cue is also modulated (volume and pitch) in UE4 but very slightly.
Both audio cues are implemented differently. We want to hear the full sound of shooting not stopped even when the projectile hit target instantly after shooting not just to avoid strange sound glitch but to follow animation which always plays full sequence. For that reason, the first part of the sound was implemented into the Player animation sequence which is played when player press Left Mouse Button (or equivalent on Gamepad). Also, this sound is played as 2D because the camera is always in the same position behind the player.
Looped audio cue is attached to Projectile Particle Effect and plays as long as the projectile is active. Only a very short loop was needed in this case as the projectile fly very fast. To keep realism this sound is modulated by the Doppler Effect which changes the pitch of sound depending on the distance between Projectile and Player the same way how it is happening in the real world.
Behind The Wall Club Music:
In this case, I made something that I have not seen anywhere else. While working on Club Music that will be heard only as behind the wall (Player can get only to the front of the Club) I remind myself that in real-world situations when very loud bass-heavy music is played... walls are shaking making a distorted buzzing sound. In DAW I took typical steps to create 'behind the wall' effect that everyone knows: reverberation and low pass filtering. Then I created my own system whereby adding new music can automatically generate the effect of 'shaking walls'. The only thing that needs improvement is a sound that was recorded with a handheld recorder and can be improved by recording it again with the Hi-End microphone. But the current result is good enough for Show Reel / Demo. Music and 'Shaking Wall' SFX are rendered separately for each music track. They are mixed into one 'Music Selector' Blueprint where both have different physical properties. Music in ShowReel include: - Blanche DuNoiz - Hollywood is Dead (my own track); - MirrorMe - Sumdub (WIP Unreleased Demo) - my friend demo track that he sent to me a long time ago
Player Start Game Sequence
8 hours. Around 60 effects and 30 channels. This is how much it takes to make 5 seconds of audio. The theme came to my mind instantly: Player is Muriel. Muriel has wings. Who have wings? Angels. So Angelic Choir heralding the coming of an angel is the theme. The real fun came with the sound design of electronic mechanical elements that match the animation of Muriel's transformation. Here came inspiration from Transformers Movies. I made a lot of alterations before I concluded that I got what I want. Then I made some tweaks to animation with particles so the next day I made sound effects to these particles too. Audio is a mixture of cybernetic sounds of mechanical body parts and fantasy type of sounds for particles.
This one is a huge military machine so I made for him the sound of mechanical movement of his legs. The source was random mechanical noise. Then it has been heavily modulated with Ring Modulator, Phaser, Tremolo and Comb Filtering.