Synthesised audio gaming applications?

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3 comments, last by eoinmullan 16 years, 10 months ago
Hi all, I am currently doing a PhD on physically informed audio synthesis for virtual environments. This means creating a virtual environment in which all the sounds effects that are heard are synthesised from information on the objects involved in creating the sound e.g. dimensions, weight, material, and how the objects collided, e.g. velocity, impact location. Two reasons I have for undertaking this work are: i) To create a more immersive environment because sound effects should be more realistic and the same sound would not be heard more than once as is the case when sound samples are used. ii) To speed up the process of prototyping and creating games as a sound designer will not have create a sound sample for every case sound is required. I am interested in finding ideas from gamers and game designers/creators for how physically informed audio synthesis could enhance a game by making things possible that aren't possible with sampled sounds. Can anyone think of scenarios where subtle differences in sounds contain information needed to progress/succeed? I would aim to create these scenarios as a means to demonstrate my research work. All suggestions are welcomed, Many Thanks, Eoin
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Just as a comment, some game physics engines already manage objects as dimensions, weight, material.

Of the top of my head, I can imagine a game where you have to slightly modify the density of an object to solve something (gravitational puzzles?) and the easiest way of showing this density change could be by sound.

Something like "*ding*, *ding*, *dinng*, *dinng*, *binnng*, *binnnggg*. That's it. Throw the steel ball".

One thing I've been thinking of for my own projects is pretty simple - finding secret passages and the like. I'm envisioning a spider drone that walks along the floor, walls, and ceiling, with the player being able to hear its footsteps and the footsteps changing when the drone hits a hollow area. That's totally doable with repetitive tones though, and doesn't need what you're talking about.

You might be able to create some kind of "blind" game which combines very basic sight information with detailed echolocation. I'm thinking of something like just getting a colored ball of light on the screen at the point of echoing. Dunno how you'd work differing materials into that, though.

One concern I would have for your system is that I think it would still generate repetitive sounds. Consider a person walking on a flat chunk of ground. In the real world, that person's stride is irregular and the surface has minor variations; in a game, the stride is likely to be very regular, as is the surface. Thus in the former case the sound generated by each footfall is slightly different; in the latter, each footfall sounds the same. Of course, you could apply minor random factors to the player's stride and the surface properties, but that seems like just a more expensive way of modifying the footfall sound directly.
Jetblade: an open-source 2D platforming game in the style of Metroid and Castlevania, with procedurally-generated levels
Personally I'm having trouble picturing many applications for synthesised sounds. Typically every other area of audio has moved from synthesised to sampled sounds wherever practical, and provided variations on this via post-processing.

As Derakon, perhaps the best example is footsteps, of varying foot types on different surfaces, at different speeds, though Thief manages to provide gameplay related to this using samples. Procedurally generating them might work equally well though.

Maybe I'm just not being imaginative enough, but most things in game audio to date can be easily approximated with a sample and a bit of DSP.
Regarding footsteps, synthesizing sounds would be less demanding on memory. I will be creating a model that takes some parameters, e.g. physical parameters like object size, material etc... or audio information like frequencies and corresponding damping parameters. This information will just be numbers and therefore use very little memory. To create a sound the model will need an impulse which will be similar to a sound sample but a lot shorter, again saving memory. This impulse can be modified randomly before being given to the model and if the models physical/audio parameters are modified too there will be an almost infinite set of sounds that can be produced from a small input set. Furthermore the input parameters can reflect the conditions of the environment adding to realism. The technique will require more processing than playing a sample and I think the amount would be comparable to applying DSP to a sample.

With regard to creating a scenario where samples cannot be used, consider a game where unique objects can be created as part of the game play. I should be able to create sound effects for that object but it will have been impossible to record sound samples for an object that didn't exist when the game was created. Maybe someone can use this idea to come up with a situation requiring synthesized sounds.

Thanks for the suggestions and please keep them coming!

Eoin

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