Range and tempo limitations for music box arrangements

A
Range and tempo limitations for music box arrangements
  1. File Format and Track Length Restrictions
    • File Format: Only single-track MIDI files are supported; other music formats are not supported.

    • Track Length: When playing via the app, each song is limited to a maximum of 30 minutes (to prevent insufficient storage space on the mobile device). No length restriction applies when playing directly from a computer DAW.

    • Storage Method: During live performance, audio files can be stored in the music box’s internal memory or read via a USB flash drive (for easy on-the-fly adjustments and changes before performances).


  2. Musical Range Restrictions
    • N20 Range: Full notes from C3 to A5, equivalent to the white keys of a piano (excluding semitones/black keys).
    • N40 Range: F2 to A6, excluding F#2, G#2, A#2, and C#3.
      (Middle C = C3 = 261.6 Hz).


  3. Maximum Polyphony
    Refers to the maximum number of notes that can be struck simultaneously:
    • N20 Model: Maximum polyphony of 7 notes.

    • N40 Model: Maximum polyphony of 10 notes.


  4. Playback Speed Limits
    • For Different Pitches: If the melody consists of notes that leap (not repeated same pitch), Muro Box’s playback speed is virtually unlimited. It only takes 0.001 second to process different pitches. Even at an extremely fast tempo of ♩= 375 BPM with 1/64th notes (the smallest unit in the app), Muro Box can still play. Dense chromatic runs like those in “Flight of the Bumblebee” need not worry about missed notes.

    • Repeated Note Limit (Same Pitch): Due to the mechanical return time of the note comb, a single pitch cannot be struck more than five times per second, i.e., a maximum of 300 strikes per minute. When a song’s tempo ♩ ≥ 75 BPM and consecutive sixteenth notes (same pitch) are played, note dropouts may occur. In such cases, it is recommended to delete one of the repeated notes.


  5. Motor Speed Selection
    In the app, tap the gear icon at the bottom right, go to “Settings” > “Music Box Settings” to adjust the motor speed percentage:
    • High Speed: Smoother playback, less timing drift, but louder motor noise.

    • Low Speed: Quieter motor noise, but rhythm stability is more susceptible to melodic variations.


  6. Latency
    • Fixed Latency (~100ms): When playing from a computer DAW, due to the physical structure of the music box, there is a fixed delay of approximately 0.1 seconds from receiving a MIDI signal to actual sound production (equivalent to one sixteenth note at 120 BPM). If playing together with other instruments, it is recommended to send the MIDI signal 100ms earlier (pre-delay) in the sequencing software to align the beat.

    • Motor and clutch mechanics can cause slight torque fluctuations during playback, resulting in a random backward shift of up to 20ms in note timing (similar to a swing feel).

    • Startup Latency: When starting from a stop, the motor requires “warm-up time” to spin up from zero, so sound does not begin immediately. (In MIDI Controller mode, as the motor remains continuously spinning in standby, this latency does not occur.)


  7. Volume and Live Sound Reinforcement Recommendations
    Muro Box’s acoustic output level is comparable to a traditional paper-roll music box, not a large grandfather clock-style music box. If performing together with other instruments or in public settings, it is advisable to use an external microphone to capture the sound and amplify it through speakers to ensure the music box is not masked by other instruments.