# NNS_SndPlayerSetTrackModSpeed

## Syntax

      #include <nnsys/snd.h>

      void NNS_SndPlayerSetTrackModSpeed(
              NNSSndHandle* handle,
              u16 trackBitMask,
              int speed );

## Arguments

`handle` | The sound handle pointer.
`trackBitMask` | This is the track bit mask.
`speed` | Modulation speed value. Takes a value between 0 and 255.

## Return Values

None.

## Description

Changes modulation speed for the sequence track.

This function changes the modulation speed of the sequence that is bound to the sound handle `handle`. This function does not perform any action if the sound handle is invalid.

Use `trackBitMask` to specify the tracks to be set. The tracks are identified from the lower bit in sequence: Track 0, Track 1, Track 2 .... All tracks that have enabled bits will have their modulation speed changed. For example, to change the modulation speed of Track 2 and Track 5, use (1 << 2) | (1 << 5) , i.e., 0x0024.

The default value for `speed` is 16, which corresponds to about 6.4 Hz. When the value doubles in size, the frequency also doubles.

### Note

If a modulation speed value is already set inside the sequence data, the value set later is the one that is valid.

## See Also

None.

## Revision History

2004/06/01 Revised to state that the Sound Handle binds to the sequence
2004/04/01 Initial version

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