Paah

Many musical tracks in the New Super Mario Bros. series incorporate sound effects that enemies and objects on-screen may briefly react to. These sounds are usually vocal samples that punctuate the background music at the end of a melodic phrase. The main sample used is "Paah" from the Best Service Voice Spectral sample CD. As a result, the sounds and gameplay mechanics are commonly described as bahs, bahps, and similar names. There are other sound effects with the same effect and similar placement in the music.

As it could otherwise be assumed that the in-game characters do not, their reaction to these sound effects may be considered to break the fourth wall.

Super Mario 64 / Super Mario 64 DS
The jingle that plays immediately after entering a painting in Super Mario 64 uses the "Paah" sample to play the first six notes of the Ground Theme from Super Mario Bros. Unlike later uses of the sample, it has no gameplay effect. New Super Mario Bros. may have repurposed the sample due to its presence in the Nintendo DS remake, Super Mario 64 DS.

New Super Mario Bros.
New Super Mario Bros. is the first game to give the "Paah" sound a gameplay function. It plays in the main, underground, athletic, desert, beach and lava themes, which some enemies and objects will react to in their respective levels. A table summarizing entities' responses across different New Super Mario Bros. games can be found below.

In certain themes, the "Paah" vocals are replaced with other sounds with the same function. The main and athletic themes use the "Paah" sample, while the underground, desert, beach, and lava themes use a similar "Taaaa" sample from the same CD. The underwater theme uses an ascending cartoon xylophone glissando.

Pre-release versions of New Super Mario Bros. used an orchestra hit in place of the final game's vocal samples.

New Super Mario Bros. Wii
While New Super Mario Bros. Wii uses new overworld, underground, and athletic themes, the "Paah" sound reappears in these new versions, serving the same purpose. It also appears in the new desert, beach, forest, snow, and lava overworld music, as well as the lava underground music.

There are two points in the tower theme that act as "bah"'s; each is at the start of a slow trill that plays on bass marimba and strings near the beginning of the loop. In the castle theme, the sound of orchestral cymbals is used in place of "bah"'s.

Because Super Mario Run lacks the "bah" mechanic, music reused from New Super Mario Bros. Wii in that game, such as the desert theme, has had the vocal samples removed. This is untrue of other reuses of these themes.

New Super Mario Bros. 2
In New Super Mario Bros. 2, the "Paah" sound reappears in the new ground theme and athletic theme, as well as the desert, beach, forest, snow, lava overworld, and lava underground music reused from New Super Mario Bros. Wii. The xylophone glissando also reappears in the underwater theme. Additionally, this game is the only game in the series to incorporate "Paah" vocals in the music of Ghost House, tower and castle levels. The latter two also feature the sound effects that were previously used in their New Super Mario Bros. Wii renditions in place of the "bah" vocals, but stage elements now only respond to the vocals.

The vocals with the "bah" effect are distinct from the new "yah" or "lah" samples accompanying the ground and athletic themes, which play alongside the melody in the overworld theme and instead of it in the athletic theme. As the melody in these themes is otherwise the same as in their New Super Mario Bros. Wii counterparts, enemies and objects only react to the bahs that were present originally.

New Super Mario Bros. U
In New Super Mario Bros. U and its port, New Super Mario Bros. U Deluxe, the "bah" sounds reappear in the underground, desert and forest overworld music from New Super Mario Bros. Wii. Additionally, they are present in the new ground, athletic and snow themes. The xylophone glissando sound appears again in the underwater theme. New Super Luigi U, an expansion to this game, simply reuses the music from New Super Mario Bros. U, so the same actions occur when the "bah" sound is played.

Super Mario Maker series
The Super Mario Maker games reuse the underground, underwater, desert, forest and snow overworld music from New Super Mario Bros. Wii, and the overworld and athletic music from New Super Mario Bros. U. However, enemies in these games do not react to the music, so the "bah" sounds serve no functional purpose.

Table of reactions
The table below lists the reactions of various elements in the New Super Mario Bros. games to these sounds. Many of these reactions are aesthetic, but some can have a small effect on gameplay, such as enemies making adjustments to their position instead of walking at a constant rate.