;;; -*- syntax: common-lisp; base: 10; mode: lisp -*-

(definstrument fm-bell (startime dur frequency amplitude 
			amp-env index-env index
		        &optional (degree 0.0)
				  (distance 1.0)
				  (reverb-amount 0.005))
  (let* ((beg (floor (* startime *srate*)))
	 (end (+ beg (floor (* dur *srate*))))
	 (fmInd1 (hz->radians (* 32.0 frequency)))
	 (fmInd2 (hz->radians (* 4.0 (- 8.0 (/ frequency 50.0)))))
	 (fmInd3 (* fmInd2 0.705 (- 1.4 (/ frequency 250.0))))  
	 ;;(no hz->radians because included in fmInd2)
	 (fmInd4 (hz->radians (* 32.0 (- 20 (/ frequency 20)))))
	 (fmenv 0.0)
	 (loc (make-locsig :degree degree 
			   :distance distance 
			   :reverb reverb-amount))
	 (mod1 (make-oscil :frequency (* frequency 2)))
	 (mod2 (make-oscil :frequency (* frequency 1.41)))
	 (mod3 (make-oscil :frequency (* frequency 2.82)))
	 (mod4 (make-oscil :frequency (* frequency 2.4)))
	 (car1 (make-oscil :frequency frequency))
	 (car2 (make-oscil :frequency frequency))
	 (car3 (make-oscil :frequency (* frequency 2.4)))
	 (indf (make-env index-env index dur))
	 (ampf (make-env amp-env amplitude dur)))
    (run
     (loop for i from beg to end do
       (setf fmenv (env indf))
       (locsig loc i 
	       (* (env ampf)
		  (+        (oscil car1 (* fmenv fmInd1 (oscil mod1)))
		     (* .15 (oscil car2 (* fmenv 
					   (+ (* fmInd2 (oscil mod2))
					      (* fmInd3 
						 (oscil mod3))))))
		     (* .15 (oscil car3 (* fmenv 
					   fmInd4 
					   (oscil mod4)))))))))))