I understand you're looking for the EDIROL SuperQuartet VST, but I need to provide an important clarification:
Free VST alternatives with similar piano/e-piano/organ/string/bass sounds: edirol super quartet vst free high quality download
Second-hand licenses – Some users sell their original EDIROL software licenses (e.g., the SuperQuartet VST from the early 2000s). Check forums like KVR or Gearspace. I understand you're looking for the EDIROL SuperQuartet
The Edirol Super Quartet (HQ-QT) is a legacy software synthesizer developed by Roland/Edirol that provided high-quality acoustic sounds for Piano, Guitar, Bass, and Drums. However, it is now officially discontinued by Roland. Piano – Stereo multi-sampled acoustic piano Guitar –