Rename filter flags: --highpass to --lowcut, --lowpass to --highcut; clarify docs and usage

main.go

@@ -65,6 +65,14 @@ 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)",
+			},
 		},
 		Action: func(c *cli.Context) error {
 			// Read sweep WAV file
@@ -82,8 +90,22 @@ 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")
+			if lowcutHz > 0 {
+				log.Printf("Applying low-cut (high-pass) filter to recorded sweep: %.2f Hz", lowcutHz)
+				recordedFiltered = convolve.ApplyHighpassButterworth(recordedFiltered, recSampleRate, lowcutHz)
+			}
+			if highcutHz > 0 {
+				log.Printf("Applying high-cut (low-pass) filter to recorded sweep: %.2f Hz", highcutHz)
+				recordedFiltered = convolve.ApplyLowpassButterworth(recordedFiltered, recSampleRate, highcutHz)
+			}
+
 			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...")