You can tell they composed this soundtrack with something way more capable (like the Roland MT-32 or SC-55) and downgraded it to 3 voices for the Tandy version. Just listen to the difference:

https://youtu.be/h8aiK7gW34o

Edit: Direct comparison of QFG3 intros on different sound cards:

https://youtu.be/ivRRPPFMPJc

Quest For Glory I & IIs soundtracks seemed to be translated with more care to the Tandy/PC Jr sound chip:

https://www.youtube.com/watch?v=9uP4w6hp_QA&t=124s