In-Game: Add support for setting an individual audio instance's gain higher than 1

[gl326]

Is your feature request related to a problem?

Currently we're using Gamemaker's audio_bus feature set as a mixing tool to control the volume of grouped assets. This has been an overall improvement of our own custom-writ "bus" system we used previously, but it has some limitations in how it interacts with audio instances.

With the way our audio designers expect to work with audio assets, a bus can be used to turn down a group of assets, but then they want to adjust the gain on individual audio instances using the bus volume as a center. This means that some sounds should be turned down lower, but other sounds need to be turned up. The issues is that, because audio instances don't get any louder when their gain is set over 1, this means that it's impossible to turn sounds up, even if the final output after passing through a bus would be less than 1.

For example, consider an audio instance whose gain is set to +6dB playing through a bus set to -6dB. Any audio designer would assume that the output volume would be 0dB. However, because the asset is invisibly capped at +0dB, the final output audio is at -6dB.

Describe the solution you'd like

Setting the gain of an audio instance to a value greater than 1 should make it louder.

Describe alternatives you've considered

This is possible in Gamemaker if we make use of a "Gain" audio effect - this actually allows you to set gain greater than 0dB. For now we are using this as a workaround.

However, it introduces more code and data to manage than what seems necessary. This audio effect is useful for situations where we want to dynamically adjust a playing sound's gain, but for "fire and forget" situations where we simply want to play a sound at a specified volume, it's an overwrought solution.

Another possible solution we considered is artificially doubling the volume of every audio bus we create and halving the volume of every played audio asset, so our audio effectively sounds identical but has artificial headroom above every asset's volume. If audio busses can have their volume set to greater than 0dB then it would work (I haven't tested it). However, it's a janky and strange workaround.

In either case, since it's technically possible to get the output we want with the game engine, it feels like it should also be possible to achieve that output by using the most simple, obvious and direct method (set the gain on a played audio instance to a value greater than 1).

Additional context

No response

[toby-yoyo]

Removed a historic upper limit on source gains, which are the product of voice (instance), asset, group and emitter gains. This means that the constituent gains should always have an effect if set above 1.

Listener (master), bus and effect gains were untouched as they already had this behaviour.

Here's a little test project for this: gmb-5580-x.zip

Please be aware that audio devices/operating systems can sometimes attempt to normalise the audio stream in order to protect the user from what would otherwise be very loud sounds. As a result, you may find that increasing gains might have an inconsistent effect - we have no control over this.

[YYBartT]

Added a note on all gain setter function pages explaining that either OS or audio device might change the sound's final amplitude.

[caitlinrmcintyre]

Verified in IDE v9.9.1.676 Runtime v9.9.1.818, thanks.

[caitlinrmcintyre]

Verified changes are in the manual.