higher one are available at any moment. Any number of notes within these two *octaves* can be played one after another, for example: ``` 10 a$="cfedafgCFEDAFGCC" 20 PLAY a$ ``` If you want to span more than just two *octaves*, you can change the overall pitch of the *channel* playing by using the *octave command* **O** followed by a number from **0** to **8**. If you do not specify an *octave* (as in the example above), this defaults to **5** (the range containing *middle C*). The *octave command* remains in force for all notes following it until a new *octave* command is given. This program lets you hear the same tune played in a higher *octave* (just add the **O7** to your earlier program): ``` 10 a$="O7cfedafgCFEDAFGCC" 20 PLAY a$ ``` Try changing the *octave* number progressively to hear the full pitch range which your ZX Spectrum Next's *PSGs* can produce. Since each pitch range covers two *octaves*, two adjacent ranges overlap. For example, the high part of **O4** contains the low part of **O5** (see *Figure* below). The following diagram shows how you can create different notes using the **PLAY** *octave command*. As mentioned previously, the command **O** followed by a number from **0** to **7** sets the current *PSG* to a range of two *octaves* beginning with a *C*. The diagram shows the complete range of notes covered by **O3**, **O4**, and **O5**. Adjacent *octave* ranges overlap, so the same notes appear in the upper part of one range and the lower part of another. Individual notes within an *octave* range are set by using the letters **c** to **b** in lower case for the lower notes and **C** to **B** in capitals to give the notes in the upper *octave*. Placing a **#** before any note letter gives a sharp note – a **$** flattens it.  ``` C D E F G A B C D E F G A B C D E F G A B C D E F G A B c d e f g a b C D E F G A B “Octave” 3 c d e f g a b C D E F G A B “Octave” 4 c d e f g a b C D E F G A B “Octave” 5 ``` *Fig. 18 – Octaves and Pitch values for making music with **PLAY*** ### Note duration If you do not specify the length of each note, they will all be played at the same length (as *crotchets*) as in the examples above. You can fix the length of any note or series of notes by prefixing it with a number from **1** to **12**. This program lets you hear the different note du-