I haven't peered under the hood of the DX11, I do have a TX81Z though which is the rack-mounted equivalent. I'm pretty sure the fundamental design would be more

I haven't peered under the hood of the DX11, I do have a TX81Z though which is the rack-mounted equivalent. I'm pretty sure the fundamental design would be more-or-less identical. There definitely would have been many small improvements in the design between the DX7, and the DX11. Aside from the DX11 supporting different waveforms (actually truncated sine waves), people have said that the large difference in sound between the successive generations of Yamaha's FM synths comes from using a more abridged sine table. The shorter the table, the more thin, and metallic the sound.