Oh I love the dog barking sound. The FREE music is so much better with the ambience track.
The BGMs are .SND/ DTPK files within the disk archive , once you convert them (should have a snd player? ) you can find out which track it is and then replace it with the seagull track
Are we talking about the remasters? Because I get a bunch of dat, paks, pakf, and riff files. I open the paks and pakf files with IPAC browser, but I can't find any SND files.
Hmm the PC files are SND with DTPK headers but none of these match the ones in the dreamcast scene/sound folder, I can guess they may have re-encoded them to work properly in a Win/PCM environment, I dunno but hoperfully converting them will be easier than snd2wav (once the wulinshu hash list is searchable you should be able to identify the audio files to change, it will have the filename 'FREE. something')
The tools are likely out there, if generated sound is anything like voices
Are you ever in the area long enough to be annoying?
barking and bird sounds are in amb**.snd files, look for amb in https://wulinshu.raymonf.me/#/ each amb for deffirent area and scene. Files can be opened for example in Audacity as RAW 32-bit pcm files. The problem is that I don't know exact offsets and sizes of samples and doing it manually is quite time consuming.
Edit:I made one that should work in Yamanose on what equivalent of first disk of Shenmue