In Cakewalk by BandLab, TTS-1, the default GM/GS synthesizer, has been discontinued, and its future functionality is uncertain. If you still have TTS-1 from a previous version, you can carry it forward, but it's not included in the latest releases. Alternatives like Cakewalk Sound Center, NoteTrack, or third-party VST plugins are available, but they don't fully replace TTS-1's GM/GS compatibility. For a true GM experience, external hardware or a dedicated GM VST like Coyote or SynthFont may be better options. However, these require more setup and may not fully replicate TTS-1’s seamless handling of GM files.