[Stk] Stk tick Questiion

[masahiko hagio]

I'm newbee Xocde synth making,so I found  Cocoa STK .
now, I'm studing hard about Xcode baisic and reading  the Examples  
( HelloStkx.zip）

so,I want to add effects , I added code is below....


------------------------------------------------------------------------ 
--

int tick(char *buffer, int bufferSize, void *dataPointer)

	{
	WaveLoop *sine = (WaveLoop *) [(id)dataPointer sine];
	register StkFloat *samples = (StkFloat *) buffer;

Chorus Chorus;
Chorus.setModDepth([(id)dataPointer amp] * 2.0);
Chorus.setModFrequency(5.0);

	for ( int i=0; i<bufferSize; i++ ) {
	//	*samples++ = delay.tick( sine->tick());
	*samples++ = Chorus.tick(sine->tick());
		}
	return 0;
			};
------------------------------------------------------------------------ 
--

build and cmpile is  no problem, but,  sound is strange...
I konw it couse adding  code is wrong, or  I do not understand   
[ tick] meanings...