[DOS] CD music is not played during the gameplay

[MoskovchenkoD]

Summary

BizHawk's DOS core doesn't play CD music, if a game uses CD as an external storage for non-mandatory resources.

Tested games:

• Shadow Warrior
• Chasm: The Rift

Repro

1. Launch DOS (DOSBox-X) core using a game distributed on a CD ROM
2. In the menu bar, select "DOS"
3. Perform the following adjustments:

• Configuration Preset: [1999] IBM Thinkpad 240
• Mount Writable Hard Disk Drive: 241 Mb (FAT16) or higher, to have enough space.
• Sound Blaster Model: Sound Blaster 16 (optionally). "Auto" results in the same outcome.

4. Reset the core or re-launch Bizhawk and select a DOS game (repeat point 1)
5. Install any of the provided games (shown on videos below)
6. Launch the game.
   6.1. In case of Chasm, type "chasm" to launch the game.
   6.2. In case of Shadow Warrior, type "setup" and choose Sound Blaster as its Sound FX chip for the game. After you save the settings, a config file necessary to start the game is generated. Then type "sw" to launch the game
7. Take a closer look at the audio being played.

Recording a video using BizHawk A/V Writer doesn't help.
Changing Sound Blaster IRQ option in DOS settings doesn't help.

Expected

Once the game starts, the music is played alongside voice lines and sound effects.

Actual

Once the game starts, the music isn't played.

Host env.

• BizHawk 2.10.1 dev build at 236ff74; Win10 Pro 22H2; AMD/Nvidia

Comparison screen recordings

The following recordings sequentially record the process of installing and launching each of the mentioned games on DOSBox-X (2025-02-01 release) and BizHawk. DOSBox-X doesn't have these issues.

Shadow Warrior
Chasm: The Rift
Warning: Shadow Warrior plays very loud music in DOSBox-X. Please, keep the volume low around 1:15! I left the timecode in the video.

Here is its configuration file. I tweaked the CPU and memory, but Sound Blaster settings remained unchanged. Although, with the default settings, there was no issue as well.
dosbox-x-2025-Feb-01-conf.zip

[SergioMartin86]

You can assign me to this issue. I have an idea of where to look at