How to Synchronize with Metronome:

Each line of Melody notes is visually represented as a concentric ring of light, which begins at the edge of the melodic aura and shrinks toward Octavia’s feet, where the ring disappears as the sound of the notes are played.
In order to gain buffs, players must time their actions to sync with the moment a concentric ring is centered on Octavia, as the sound of the notes are played. A flash of light will appear below the player upon a successful sync.
Synchronize percentages are listed between 0% and 100%, and will raise or lower depending on the player's timing. Once the percentage reaches 100%, the player gains the corresponding buff.
Synchronize percentage is displayed as an icon with the current stored percentage beside the health and shield indicators on the HUD. Once synchronized, the corresponding buff icon will also be displayed with the remaining buff duration beneath and bonus percentage at the top-right of the icon.
Each player must perform actions individually to gain buffs. Sync buffs are gained per-player and are not shared between allies in range.
If a player does not perform an action when the ring disappears, their existing synchronize percentage does not decrease. however, if they do perform an action at the wrong time, their synchronize percentage resets; Meaning that players can skip certain beats and focus on precision if they cannot keep up with the Mandachord's rapid pace. This is particularly important for weapons with low fire rate / attack speed and with the vivace (movement speed) buff.
The amount of notes on one line of the Melody section on the Mandachord determines the brightness of the concentric rings.By synchronizing with jumps (default Space ), Octavia and her allies can gain the Vivace buff which increases Movement Speed by 10% / 15% / 20% / 30% for 5 / 8 / 12 / 15 seconds.
Double jump (default press Space  twice), wall climb (face wall and press Space ), and wall jump (face wall + W  + Space ) can also be used to synchronize.By synchronizing with crouching (default Ctrl ) or sliding (default W  + Ctrl ), Octavia and her allies can gain the Nocturne buff which grants Invisibility for 5 / 8 / 12 / 15 seconds.By synchronizing with ranged weapon fire (default LMB ), Octavia and her allies can gain the Opera buff, granting 12% / 20% / 25% / 30% ranged weapon Multishot for 5 / 8 / 12 / 15 seconds.
Multishot bonus stacks additively with multishot mods such as  Split Chamber.
Alternate-fire or secondary attacks on select weapons are not known to be able to gain multishot from Opera (requires testing).By synchronizing with melee weapons (default E ), Octavia and her allies can gain the Forte buff, granting 20% / 25% / 25% / 30% bonus melee weapon damage for 5 / 8 / 12 / 15 seconds.
Damage bonus stacks additively with base damage mods like  Pressure Point.Page 2How to Synchronize with Metronome:

Each line of Melody notes is visually represented as a concentric ring of light, which begins at the edge of the melodic aura and shrinks toward Octavia’s feet, where the ring disappears as the sound of the notes are played.
In order to gain buffs, players must time their actions to sync with the moment a concentric ring is centered on Octavia, as the sound of the notes are played. A flash of light will appear below the player upon a successful sync.
Synchronize percentages are listed between 0% and 100%, and will raise or lower depending on the player's timing. Once the percentage reaches 100%, the player gains the corresponding buff.
Synchronize percentage is displayed as an icon with the current stored percentage beside the health and shield indicators on the HUD. Once synchronized, the corresponding buff icon will also be displayed with the remaining buff duration beneath and bonus percentage at the top-right of the icon.
Each player must perform actions individually to gain buffs. Sync buffs are gained per-player and are not shared between allies in range.
If a player does not perform an action when the ring disappears, their existing synchronize percentage does not decrease. however, if they do perform an action at the wrong time, their synchronize percentage resets; Meaning that players can skip certain beats and focus on precision if they cannot keep up with the Mandachord's rapid pace. This is particularly important for weapons with low fire rate / attack speed and with the vivace (movement speed) buff.
The amount of notes on one line of the Melody section on the Mandachord determines the brightness of the concentric rings.By synchronizing with jumps (default Space ), Octavia and her allies can gain the Vivace buff which increases Movement Speed by 10% / 15% / 20% / 30% for 5 / 8 / 12 / 15 seconds.
Double jump (default press Space  twice), wall climb (face wall and press Space ), and wall jump (face wall + W  + Space ) can also be used to synchronize.By synchronizing with crouching (default Ctrl ) or sliding (default W  + Ctrl ), Octavia and her allies can gain the Nocturne buff which grants Invisibility for 5 / 8 / 12 / 15 seconds.By synchronizing with ranged weapon fire (default LMB ), Octavia and her allies can gain the Opera buff, granting 12% / 20% / 25% / 30% ranged weapon Multishot for 5 / 8 / 12 / 15 seconds.
Multishot bonus stacks additively with multishot mods such as  Split Chamber.
Alternate-fire or secondary attacks on select weapons are not known to be able to gain multishot from Opera (requires testing).By synchronizing with melee weapons (default E ), Octavia and her allies can gain the Forte buff, granting 20% / 25% / 25% / 30% bonus melee weapon damage for 5 / 8 / 12 / 15 seconds.
Damage bonus stacks additively with base damage mods like  Pressure Point.