feature/high-low-pass-filter (#2)

Co-authored-by: Bastian Bührig <bastian.buehrig@2bconsult.eu>
Reviewed-on: #2

main.go

@@ -65,6 +65,19 @@ func main() {
 				Usage: "Fade-out duration in milliseconds to apply at the end of the IR (default 5)",
 				Value: 5.0,
 			},
+			&cli.Float64Flag{
+				Name:  "highcut",
+				Usage: "High-cut filter (low-pass) cutoff frequency in Hz (applied to recorded sweep, optional)",
+			},
+			&cli.Float64Flag{
+				Name:  "lowcut",
+				Usage: "Low-cut filter (high-pass) cutoff frequency in Hz (applied to recorded sweep, optional)",
+			},
+			&cli.IntFlag{
+				Name:  "cut-slope",
+				Usage: "Cut filter slope in dB/octave (12, 24, 36, 48, ...; default 12)",
+				Value: 12,
+			},
 		},
 		Action: func(c *cli.Context) error {
 			// Read sweep WAV file
@@ -82,8 +95,26 @@ func main() {
 			log.Printf("Sweep: %d samples, %d channels", len(sweepData.PCMData), sweepData.Channels)
 			log.Printf("Recorded: %d samples, %d channels", len(recordedData.PCMData), recordedData.Channels)
 
+			// Optionally filter the recorded sweep
+			recordedFiltered := recordedData.PCMData
+			recSampleRate := recordedData.SampleRate
+			highcutHz := c.Float64("highcut")
+			lowcutHz := c.Float64("lowcut")
+			cutSlope := c.Int("cut-slope")
+			if cutSlope < 12 || cutSlope%12 != 0 {
+				return fmt.Errorf("cut-slope must be a positive multiple of 12 (got %d)", cutSlope)
+			}
+			if lowcutHz > 0 {
+				log.Printf("Applying low-cut (high-pass) filter to recorded sweep: %.2f Hz, slope: %d dB/oct", lowcutHz, cutSlope)
+				recordedFiltered = convolve.CascadeLowcut(recordedFiltered, recSampleRate, lowcutHz, cutSlope)
+			}
+			if highcutHz > 0 {
+				log.Printf("Applying high-cut (low-pass) filter to recorded sweep: %.2f Hz, slope: %d dB/oct", highcutHz, cutSlope)
+				recordedFiltered = convolve.CascadeHighcut(recordedFiltered, recSampleRate, highcutHz, cutSlope)
+			}
+
 			log.Println("Performing deconvolution...")
-			ir := convolve.Deconvolve(sweepData.PCMData, recordedData.PCMData)
+			ir := convolve.Deconvolve(sweepData.PCMData, recordedFiltered)
 			log.Printf("Deconvolution result: %d samples", len(ir))
 
 			log.Println("Trimming silence...")