It seems that whenever you play a sound on Android at anything other than its original volume, the first ~0.035 seconds of the sound will often play at the original volume. This doesn’t seem like much of an issue on paper, but all of my sounds are normalised, and some have very sudden attacks. In particular I have click sounds which play at a considerably lower volume when buttons are pressed, and most of the sound happens in the first 0.04 seconds of the waveform. These often play loudly when clicked on, and this problem is amplified when you turn the sound effects volume down in the game. I can fix this by putting 0.04 seconds of silence at the start of all of my sound effects, which probably won’t introduce any noticeable lag, but it’s not really ideal!
I’ve seen this on two Android devices, an LG G3 and a Samsung Galaxy Nexus. I was also able to reproduce it in Tappy Chicken by replacing the flap sound with my short click sound, and setting the volume to 0.1. It didn’t make a difference whether I played the sound wave directly, or played it inside a Sound Cue.
Thank you for bringing this to our attention. I have tested this on two projects, on the Nvidia Shield as well as the . What version of Android are you on? Does this happen every single time, including on newly created projects? Which sound did you use, was it from the Starter Content?
I was able to reproduce this using the mobile version of the SideScrollerExample project (by hooking a Play Sound 2D up to the Jump function in the SideScrollerCharacter blueprint). I tried a couple of the sounds in the Starter Content folder; I thought the explosions might cause it to happen, but they didn’t (Presumably there is some silence at the start of them). Smoke01 did cause it, however. I had to turn the Looping flag off, but when I played it with a volume multiplier of 0.1, it would often have a brief loudness at the start, before playing at the correct volume. This sound is 5 seconds long, however, so it’s not ideal for testing. Here’s the short clicking sound I’ve been using, where the bug is very noticeable: [SFX_Click.zip][1]
I have pushed 2 different modified projects to my Nvidia Shield and neither of these showed the bug that you’re describing. I did replace the sounds with the sfx_click.wav file. I’m beginning to wonder if it’s a specific set up that you’re using. Would you be able to provide me a sample of your project that you’re experiencing this issue with?
Here’s the Tappy Chicken project that I modified to play the click sound at 10% volume whenever you flap: [TappyChicken.zip][1]. When I run this on Android, some of the clicks are noticeably louder than they should be. I’ve also uploaded an Android APK that I packaged, which is [here][2]. If you can’t reproduce this on your devices, it might be specific to certain chipsets.
Thanks for providing all of the information you have for me. I have been able to replicate this and I tested it against an iOS device, which it does not happen on. With that being said, UE-21645 is the number for this report. If you have any further questions, please let us know!