You are missing pak1.pak . Ensure you copied the second retail archive into your id1 folder alongside pak0.pak . Audio / Soundtrack is missing
Downloading Quake .pak files is the foundational step for anyone looking to play the original 1996 masterpiece on modern hardware. These files—specifically PAK0.PAK and PAK1.PAK —contain the entirety of the game's assets, from Gothic textures to Nine Inch Nails' iconic soundtrack. Quake Pak Files Download