ROLAND D-70 For Sale. Linear Arithmetic Synthesizer Keyboard. Think of it as a Roland D-50 on steriods. This late 80s vintage keybd was the last and most impressive of the legendary D series. We love the range of sounds this thing can make. The onboard "DLM" bass sounds remind us of the Depeche Mode bass sounds off Violator, especially when tweaking the filter frequency in real time. And then there are the breathy pads, lovely strings, ripping guitars, etc. everyone needs!