Well, the Atari ST series were said to be one of the best computers for editing music and creating own sounds, since the built-in synthesizer chips were superior to the ones which were used in the Amigas.
I went soon out of the production business as I´ve seeked a career as a DJ...maybe I should have better sticked to creating music instead.
Even today, you can find the ST series in some studios, they´re used especially in the production of Technopop. Of course, PCs and Macs are the main machines in use now (for editing/mixing), I guess the last ST was the 1040 which appeared on the market around the late 80s.