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;nyquist plug-in
;version 4
;type process spectral
;preview linear
;name "Spectral edit shelves..."
;action "Filtering..."
;author "Paul Licameli"
;copyright "Released under terms of the GNU General Public License version 2"
;; SpectralEditShelves.ny by Paul Licameli, November 2014.
;; Updated by Steve Daulton 2014 / 2015.
;; Released under terms of the GNU General Public License version 2:
;; http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;control control-gain "Gain (dB)" real "" 0 -24 24
(defmacro validate (hz)
"If frequency is above Nyquist, don't use it"
`(if (or (>= ,hz (/ *sound-srate* 2.0))
(<= ,hz 0))
(setf ,hz nil)))
(defun mid-shelf (sig lf hf gain)
"Combines high shelf and low shelf filters"
(let ((invg (- gain)))
(scale (db-to-linear gain)
(eq-highshelf (eq-lowshelf sig lf invg)
hf invg))))
(defun wet (sig gain f0 f1)
"Apply appropriate filter"
(cond
((not f0) (eq-lowshelf sig f1 gain))
((not f1) (eq-highshelf sig f0 gain))
(t (mid-shelf sig f0 f1 gain))))
(defun result (sig)
(let*
((f0 (get '*selection* 'low-hz))
(f1 (get '*selection* 'high-hz))
(tn (truncate len))
(rate (snd-srate sig))
(transition (truncate (* 0.01 rate))) ; 10 ms
(t1 (min transition (/ tn 2))) ; fade in length (samples)
(t2 (max (- tn transition) (/ tn 2))) ; length before fade out (samples)
(breakpoints (list t1 1.0 t2 1.0 tn))
(env (snd-pwl 0.0 rate breakpoints)))
(cond
((not (or f0 f1)) ; This should never happen for a 'spectral' effect.
(throw 'error-message (format nil "~aPlease select frequencies." p-err)))
((and f0 (>= f0 (/ *sound-srate* 2.0)))
; Shelf is above Nyquist frequency so do nothing.
nil)
((and f0 f1 (= f0 f1))
(throw 'error-message
(format nil "~aBandwidth is zero (the upper and lower~%~
frequencies are both ~a Hz).~%~
Please select a frequency range."
p-err f0)))
(T (if f0 (validate f0))
(if f1 (validate f1))
(if (not (or f0 f1)) ; 'validate' may return nil
nil ; Do nothing
(sum (prod env (wet sig control-gain f0 f1))
(prod (diff 1.0 env) sig)))))))
(catch 'error-message
(setf p-err "Error.\n")
(if (= control-gain 0)
nil ; Do nothing
(multichan-expand #'result *track*)))