How to 8000hz/16000hz get or put as short* array for audio ?

[eix128]

Hi , is there any way to set audio sample rate to 8000hz or 16000hz and i want to get all array as short array.

[audioManager setInputBlock:^(float *newAudio, UInt32 numSamples, UInt32 numChannels)

And whats the float range ? is it returning between [-1,1] ?
I need in short like this:
[audioManager setInputBlock:^(short *newAudio, UInt32 numSamples, UInt32 numChannels)