The GBA port of MOTHER 2 came packed in with MOTHER, then known as EarthBound Zero. MOTHER’s port came in with a slew of improvements, such as pixel-based movement as opposed to tile-based, like the Famicom original. Not as much development went into MOTHER 2’s port, because the main focus was likely put on improving MOTHER.

Many of the samples were not carefully placed in, as a lot of them are drastically off, compared to their SNES originals. One of the trumpet samples was not properly looped, causing it to have a very violent sawtooth sound to it, instead of a soft trumpet sound. Some samples are flat-out completely different, such as the melody instrument in the second half of Smiles and Tears, or the iconic MD Seeger guitar sound from Gyiyg Strikes Back! Part 2. A lot of the samples that were imported were not tuned to the same musical “reference”, so making the MIDIs for the game was likely more difficult to get just right.

Almost every single track in the port has a distinct inaccuracy within the transcription. Many times, it’s an instrument being the wrong key, with examples like the percussion in Onett, or the organ in Welcome Home. Looking in the MIDIs on their own, the notes are properly placed, but out of key. Many of the pitch bends in the original game were not properly redone here, causing them to sound completely off, the best examples being tracks like most cave themes, Alien Invasion, or Belch’s battle theme. Sometimes, there will be missing patterns/sound channels, such as the backing leads in Snowman, or nearly everything in Battle Against A Weak Opponent.

The sound engine used in MOTHER 2’s GBA port is the same engine used for many other popular GBA games, including Pokemon Ruby, Sapphire, Emerald, Fire Emblem, The Legend of Zelda: A Link to the Past/Four Swords 2 Pak, Kirby: Nightmare in Dreamland, the Sonic Advance games, and more. This shared sound engine, usually called “M4A,” “mks4agb,” “MP2K,” or “Sappy,” provides some room for configuration so that game developers can choose how much audio quality they want to sacrifice to let the game run faster. MOTHER 1+2 sets one of these options, the “sample rate”, very low (to 10.5 KHz). This causes the sound to lose a lot of clarity (for another example of what 10.5 KHz audio sounds like, see the GBA soundtracks for Phoenix Wright: Ace Attorney 2 and 3). For comparison, the SNES’ sample rate hovers around 32 KHz, and PC audio can go up to 48 KHz (sample rates on PCs go way higher than 48kHz. In fact, DVD-Audio achieves 96kHz. The highest common sample rate I’ve seen is 192kHz). From some limited testing, we did not observe any bugs after raising M2GBA’s sample rate to 15.7 KHz.