PS1's sound files are kind of finicky when it comes to extracting the samples. With PS2 and 3, MTH literally allows you to download the file and even read from it. I can't be sure if the Proto-Sound 1 files were available back in the '90s, but they sure aren't now. I asked in a Discord server if someone could identify what type of chip the PS1 sound chip is, and they said they thought it was a 32-pin Quad flatpack. They also linked me an eBay listing to a device that could possibly read from it. If I do get my hands on a PS1 loco, I will likely do the following after removing the chip:
1. Read from it using the device
2. Make a disc image of the ROM stored on the chip
3. Import the RAW image into Audacity and see if there's any audio data
4. Calculate the source bitrate of the sounds
5. Isolate each sound sample
Would this process be possible with the PS1 chips?
