Audio distortion after version 2.1

[elQuotho]

Hi good folks,

Long time admirer, erstwhile contributor here.

I recently purchased a few Sierra titles on GOG, which currently come bundled with ScummVM 2.0.0. Wanting to take advantage of all the delightful bug fixes the ScummVM team have made since then, I decided instead to try and run them through the latest version (2.5.1), but have run into some audio issues that seem to manifest in versions 2.1 and above.

Running a fresh 2.0.0, the audio levels and quality sound as expected, but with version 2.1 and later the sound for all games I tested (KQ6, KQ7, CMI) felt at least twice as loud, and in the case of the Sierra games, is so loud in places that it results in obvious distortion (in video or game sound effects). The easiest to find example would be KQ6's Sierra intro. video: besides being much louder, the drum hi-hat around the 5 second mark and the later 'sparkle' sound effects both come through distorted for me (as well as most character dialogue).

It should be noted that I have my speakers on their lowest volume setting and they're not particularly cheap. It's a Sound Blaster soundbar with built-in sound card (connected via USB). It's set to a neutral profile with no equalizer or additional processing enabled. Lowering the volume using ScummVM's internal settings does reduce the volume, but doesn't seem to reduce the distortion, leading me to believe it's an audio processing issue and not a device output issue.

Curiously, and perhaps crucially, none of these differences appear when I'm using headphones connected to my PC, or my monitor's built-in speakers—the volume between versions isn't noticeably louder, nor can I hear any distortion. In light of that, I'd normally chalk this up to some issue between my system and soundbar (not that this has happened before), but I'm having trouble reconciling why the issue is only manifesting for versions 2.1 and later, and hope there might be a clue there.

Any ideas would be appreciated, I'm not even sure how to continue troubleshooting this.

(All ScummVM versions tested were win32 zip packages downloaded from the official site and using default scummvm.ini files.)

[criezy]

My best guess at this point is that ScummVM 2.1 may have been build with a more recent version of the SDL library and that this newer version is what is causing the issue.

A quick Google search also gave this issue that could be related: https://github.com/Interrupt/systemshock/issues/348

[elQuotho]

Nice! Replacing ScummMV 2.1's version of SDL (2.0.10) with 2.0's version (2.0.5) eliminates the distortion. And like the fellow you linked, my soundbar also registers as a 7.1 device. It's clearly too fancy. The SDL issue seems to have been fixed in version 2.0.18, though the latest ScummVM ships with 2.0.14.

Do you think I should be fairly safe running with the latest SDL minor release (2.0.20)? (Do they generally adhere to semantic versioning?) Or should I run on the older SDL?

Thank you, just so much

[elQuotho]

Never mind, version 2.5.1 won't run with SDL 2.0.5, and while SDL 2.0.20 seems to work and the distortion is greatly reduced with their current fix, the gain still feels too high. I guess I'll be playing with headphones for the foreseeable future... There are worse fates, I suppose.

Thanks again!