The GB Sounds (Japanese: ＧＢプレイヤー GB Player) is a type of Key Item exclusive to Pokémon HeartGold and SoulSilver. It is obtained from the Game Freak sound designer at the Game Freak Development Room on the third floor of Celadon Condominiums after obtaining all 16 Badges.
The item changes the background music to chiptune-like rearrangements of the tracks in the area that are similar to the original ones from Pokémon Gold, Silver, and Crystal. Sound effects and radio music are unaffected by the GB Sounds.
Despite the fact that the old-style tracks are supposed to sound like the original tracks from Pokémon Gold, Silver, and Crystal, none of them sound exactly like the originals. The acoustics sound different and many notes have other pitches. Some tracks had their tempos altered somewhat and other notes in various tracks are not even heard at all. This is due to the games using a soundfont for MIDI playback rather than generating real chiptunes. The different audio hardware between the Game Boy and the Nintendo DS would also have been taken into consideration.
Several tracks that are absent in the original Pokémon Gold and Silver have received old-style rearrangements. Examples include Global Terminal and Route 47. Despite this, none of the Battle Frontier facilities, except for the outside area and the Battle Tower, received an old-style rearrangement. Battling in the facilities at the Battle Frontier with the GB Sounds active will also result in the old-style Battle! (Trainer Battle—Johto Version) being used. This effect is reverted when battling a Frontier Brain.
Some of the original tracks from Pokémon Gold, Silver, and Crystal, such as Professor Oak and Opening Movie (Pokémon Gold & Pokémon Silver), cannot be listened to with the GB Sounds. The tracks pertaining to Team Rocket can only be listened to in the Giovanni event triggered by taking a Celebi to the Ilex Forest shrine. To solve this issue, the Pokémon Music Channel hosts the Pokémon Past Archive program every Sunday, which features these tracks in addition to a few others, such as all the Trainer encounter themes.
If active during a Bug-Catching Contest, the GB Sounds will not switch to the old-style version of National Park during the contest results; however, it'll perform the switch after the results are announced.
- Although the GB Sounds is unable to play certain old-style themes such as Radio Tower Occupied! during regular gameplay, it was programmed to play them.