How to change .wav format audio file bitrate

You can do this using LEADTOOLS Multimedia SDK with few lines of code. The code will be similar to this:

ConvertCtrl _convert = new ConvertCtrl();
_convert.SourceFile = @"test.wav";
_convert.TargetFormat = TargetFormatType.WAVE;
_convert.AudioCompressors.AAC.Selected = true;
LMAACEncoder _encoder = _convert.GetSubObject(ConvertObject.AudioCompressor) as LMAACEncoder;
_encoder.OutputBitrate = 128; // Set the BitRate
_convert.TargetFile = "result.wav";
_convert.StartConvert();

For more details see the following link:
https://www.leadtools.com/help/leadtools/v19/dh/multimedia/mm/convertctrl-startconvert.html