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GEMS Graphical User Interface.png

GEMS Graphical User Interface (alt).png

System(s): Mega Drive, Sega 32X

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GEMS (Genesis Editor for Music and Sound effects) is a Sega Mega Drive sound driver program developed by Recreational Brainware and Technopop. Commissioned by Sega of America to assist Western developers struggling with the unfamiliar sound hardware, it went on to see use in over 200 released games.


By setting aside a shared memory space that allows the driver and game to directly communicate, music can be dynamically adjusted to match gameplay and easily integrated with the game’s programming. For example, pitch or tempo can be automatically adjusted per the amount of onscreen enemies or remaining health. Unfortunately, while most sound drivers control playback speed with a single and easy-to-manipulate variable, GEMS requires the alteration of the entire track as stored in ROM to achieve the same effect.

Games which use GEMS

Mega Drive



GEMS was the first widely used tool for the Genesis after the above mentioned prototype and the SOJ tool which was not provided to us. It would take Midi files and also allow streaming directly from a sequencer to the Genesis audio chip. It was not perfect and there were a number of revisions. Midi data had to be scrubbed down to no more than 6 notes at a time, or it would crash the dev system. But it could also play samples and had the Master System audio chip supported.

David Javelosa[3]

Early Sega Genesis hardware documentation was limited in all areas, but especially in audio capabilities. Unlike Japanese composers, who were more familiar with writing sound drivers and working with FM synthesis, their Western counterparts struggled to produce quality sounds. Seeking to address this, Sega of America reached out to developer Recreational Brainware to produce a solution.

The team consisted of Jonathan Miller creating drivers and firmware, Burt Sloane programming, and Chris Grigg and Mark Miller providing the software’s overall design. The result was GEMS, a 16-bit sound driver with a focus on MIDI interactivity. Sega of America was very pleased with GEMS and went on to distribute it to their various developers and publishers. Western composers and musicians now had a more familiar and reliable method for translating their instruments to the Sega Genesis hardware.

While GEMS is a very capable driver in the proper hands, it has also grown to absorb much of the ire modern fans have for the “twangy” sounds of certain Western-produced Sega Mega Drive games. As the driver was both widely distributed to developers of all quality, and largely used by developers unfamiliar with the hardware, much of the system’s shovelware library shares a distinct (and poorly received) sound, often described as sounding like flatulence. As described by David Javelosa, "GEMS was not an easy tool, so a lot of musicians would quit before finishing a project. It all fell back to staff audio, who by that time we were re-orged into the Creative Support team."[3]

Some developers, such as Novotrade, chose to modify the driver, effectively making their own variants. Individual games such as Wayne's World also have their own modified drivers.

G.E.M.S. was definitely the best sound driver/editor that was made available to the general public during the first half of the 90's. I absolutely loved it... Before G.E.M.S., we as composers/sound designers had almost nothing.

Tommy Tallarico[4]


On September 24, 2007, drx preserved and released GEMS v2.5.

Download.svg Download GEMS (v2.5)
File: (324 kB) (info)

Production credits

Developer statements

External links