Eight and twelve-string models are both built on the same "course string" concept found on twelve-string guitars, where sets of strings are spaced together in groups of two or three that are primarily played simultaneously. These instruments typically have one of the strings in each course tuned an octave above the 'standard' string, although a fifth above is also used. Instruments with ten and fifteen strings, grouped in five courses, also exist, as do "extended-range basses" or ERBs with non-coursed string counts rivaling those of coursed-string basses.
Yet another form is the portable digital piano which is what appear to be combining the capabilities of stage pianos, but with additional features similar to a conventional digital keyboard. These digital pianos are mostly designed for various purposes such as home, studio, classroom, stage or personal use. It is similar in form to a stage piano, but much lighter in weight, and having a more compact size. Unlike stage pianos, portable digital pianos were commonly equipped with built-in amplification and loudspeakers, usually has lower cost than other types, and its sound quality were often comparable or similar to that of a regular digital keyboards due to a simpler sound synthesis system, though some models, still utilize a similar sound engine as the more advanced model lineups of the same manufacturer.
Maybe you've already got a specific brand in mind and want to see all the digital pianos they offer. All you have to do is click on the brand on the left hand side of the screen and within a few moments you'll have access to everything that's available. For that matter, you can always play is safe and stick to the top-rated items…and there are plenty of those in this selection.