How to save wav files by 16bit?

I add effects to a exits sound, and save to result = FMOD_System_SetOutput(gSystem2, FMOD_OUTPUTTYPE_WAVWRITER);

but the output wav file is 32 bit, 2 channel. I want a 16bit, 1 channel file. how to do this?

and the input wav sound is 16bit, 1 channel

soloved it:

//设置输出类型
result = FMOD_System_SetOutput(gSystem2, FMOD_OUTPUTTYPE_WAVWRITER);
CHECK_RESULT(result, LINE);

result= FMOD_System_SetSoftwareFormat(gSystem2, 44100, FMOD_SPEAKERMODE_MONO, 1);
CHECK_RESULT(result, __LINE__);