Bug892: Spec. Sel. Toolbar no longer forces selection below half project rate...

... rather, selections up to half of the maximum of project rate and all track
rates is permitted.

Also added some more cautions to the Nyquist code for spectral selection
effects, in case input frequencies exceed Nyquist for the track (as they
may now do).

plug-ins/SpectralEditShelves.ny

@@ -19,7 +19,7 @@
 
 (defmacro validate (hz)
 "Ensure frequency is below Nyquist"
-  `(setf hz (min (/ *sound-srate* 2.0),hz)))
+  `(setf ,hz (max 0 (min (/ *sound-srate* 2.0) ,hz))))
 
 (defun mid-shelf (sig lf hf gain)
   "Combines high shelf and low shelf filters"
@@ -30,9 +30,14 @@
 
 (defun wet (sig gain f0 f1)
   (cond
-    ((not f0) (eq-lowshelf sig f1 gain))
-    ((not f1) (eq-highshelf sig f0 gain))
-    (t (mid-shelf sig f0 (validate f1) gain))))
+   ((not f0) (eq-lowshelf sig (validate f1) gain))
+   ((not f1) (eq-highshelf sig (validate f0) gain))
+   (t
+    (validate f0)
+    (validate f1)
+    (when (= f0 f1)
+      (throw 'error-message "Please select a frequency range."))
+    (mid-shelf sig f0 f1 gain))))
 
 (defun result (sig)
   (let*
@@ -48,8 +53,6 @@
     (cond
       ((not (or f0 f1))
           (throw 'error-message (format nil "~aPlease select frequencies." p-err)))
-      ((and f0 f1 (= f0 f1)) (throw 'error-message
-                                    "Please select a frequency range."))
       ; shelf is above Nyquist frequency so do nothing
       ((and f0 (>= f0 (/ *sound-srate* 2.0))) nil)
       (T (sum (prod env (wet sig control-gain f0 f1))