In the late '80s and early '90s, sound cards were not common—quite the opposite. The investment at that time was on par with what a dedicated video card costs today, but it was worth paying the high price to escape the horrible internal speaker. In fact, sound card hardware, especially the Yamaha YM3812, became so popular that some manufacturers directly launched what we can now call "Sound Blaster keyboards".
First, there were AdLib cards. Then, the market made room for Creative's Sound Blaster. Users began to enjoy glorious independent channels with sounds that were previously impossible to reproduce on a computer, and software compatibility soon followed. The "tyranny of the internal speaker" had fallen.
Today, the vast majority of computers use an integrated sound solution, while dedicated cards are applied to more specialized tasks that require going beyond basic support. But the hardware in early sound cards was not something designed exclusively "for computers". That same technology reached several keyboard models, which in a way can be called "Sound Blaster keyboards" (without Creative's involvement, of course).
Sound Blaster keyboards
Basically, this whole movement revolved around the Yamaha YM3812. Nine programmable channels, with the option to give up three to activate a "percussion mode" that gave it even more flexibility. Not surprisingly, Yamaha was the company that best took advantage of the YM3812's resources, placing several 49- and 61-key models on the market between 1986 and 1994.
The most advanced models had sliders to adjust functions like wave style, spectrum, and modulation. Some of these keyboards were presented as "learning" tools, or directly "for children", which is why they don't have such a high price today, assuming we can even find one.
The most curious yet obvious fact is that all these keyboards had exactly the same sound, and what Yamaha did was add chips in parallel to add elements like PCM support. Finally, the market received even more economical variants, including the YM2413, which essentially reduces the wave, spectrum, and modulation controls to a single channel, with the rest "following" those parameters.
In summary: If you come across someone asking a reasonable price for a Yamaha keyboard, check the video description. It could be a small historical audio gem waiting to be discovered.
