Which scale must a performer, composer, and listener all possess

The statement "Which scale must a performer, composer, and listener all possess" could be interpreted in different ways depending on the context, as the term "scale" could refer to various concepts in music and beyond. Considering the musical context, let's explore some possible interpretations:

1. **Musical Scales Knowledge**: In the context of Western music theory, we might be talking about the knowledge of musical scales such as major, minor, pentatonic, chromatic, whole tone, and various modes (such as Dorian, Phrygian, etc.). All three individuals – performer, composer, and listener – can benefit from understanding these scales:

- **Performer**: Needs to understand and be able to play/sing the scales to perform pieces of music accurately.
- **Composer**: Employs scales as a foundational tool to create melodies, harmonies, and the overall form of a piece.
- **Listener**: Having an understanding of scales can enhance the appreciation of how music is structured and created, though a deep knowledge is not always necessary for enjoyment.

2. **Proficiency Scale**: This might refer to a level of proficiency or skill. In this sense, the scale is a metaphorical measurement of one's ability:

- **Performer**: Must have a high level of proficiency in their instrument or voice to execute the technical demands of a composition.
- **Composer**: Also needs a high skill level to create complex and engaging pieces.
- **Listener**: While not required to have musical proficiency, having some knowledge can enhance the listening experience and understanding.

3. **Pitch Recognition Scale**: This refers to the ability to identify and reproduce pitches:

- **Performer**: Needs accurate pitch recognition to play in tune and harmonize.
- **Composer**: Uses pitch recognition to transcribe and imagine new music.
- **Listener**: Although not a requirement for enjoyment, the ability to recognize and understand pitch and tonal relationships can enrich the listening experience.

4. **Rating Scale (e.g., for Evaluating Performances)**: In contexts like competitions or academic settings, there might be a scale used for evaluation:

- **Performer**: Aim to achieve high marks on this scale by excelling in their performance.
- **Composer**: Their compositions might be judged based on originality, craftsmanship, etc., as part of a rating scale.
- **Listener**: In some cases, listeners might also be part of a jury or a public vote, using a rating scale to express their preferences.

In essence, what "scale" means in this context heavily depends on the specific knowledge or skill being referenced. For general purposes, understanding musical scales tends to be the most common alignment between performers, composers, and listeners.