X-Git-Url: https://main.carlh.net/gitweb/?a=blobdiff_plain;f=libs%2Fardour%2Fardour%2Fdsp_filter.h;h=994d8725ea418576c6c3edacfacd779f49f8dcb1;hb=02db39c1bc63da52c21d77cc8f840d5d3233f301;hp=ddf61075cd642f4cea726587f17fcbf153c8dc1e;hpb=9a8a164930d02d433175eecef9d0e7119edfa16d;p=ardour.git

diff --git a/libs/ardour/ardour/dsp_filter.h b/libs/ardour/ardour/dsp_filter.h
index ddf61075cd..994d8725ea 100644
--- a/libs/ardour/ardour/dsp_filter.h
+++ b/libs/ardour/ardour/dsp_filter.h
@@ -193,7 +193,7 @@ namespace ARDOUR { namespace DSP {
 	};
 
 	/** Biquad Filter */
-	class LIBARDOUR_API BiQuad {
+	class LIBARDOUR_API Biquad {
 		public:
 			enum Type {
 				LowPass,
@@ -211,8 +211,8 @@ namespace ARDOUR { namespace DSP {
 			 *
 			 * @param samplerate Samplerate
 			 */
-			BiQuad (double samplerate);
-			BiQuad (const BiQuad &other);
+			Biquad (double samplerate);
+			Biquad (const Biquad &other);
 
 			/** process audio data
 			 *
@@ -228,6 +228,13 @@ namespace ARDOUR { namespace DSP {
 			 * @param gain filter gain
 			 */
 			void compute (Type t, double freq, double Q, double gain);
+
+			/** filter transfer function (filter response for spectrum visualization)
+			 * @param freq frequency
+			 * @return gain at given frequency in dB (clamped to -120..+120)
+			 */
+			float dB_at_freq (float freq) const;
+
 			/** reset filter state */
 			void reset () { _z1 = _z2 = 0.0; }
 		private: