Merge pull request #16 from jyrkialakuijala/main

lifting the phase information into spatialization

scripts/upmix.py

@@ -35,7 +35,7 @@ def run(str):
 print("playing", file)
 run('cp "' + file + '" /tmp/input.wav')
 
-run("sox /tmp/input.wav -b 24 /tmp/down-dry.wav gain -10 rate 48k trim 0 80")
+run("sox /tmp/input.wav -b 24 /tmp/down-dry.wav gain -10 rate 48k trim 0 8")
 
 run("./build/revolve /tmp/down-dry.wav /tmp/16speakers.wav")
 
@@ -51,7 +51,7 @@ def run(str):
 
 run("./build/driver_model /tmp/down3-20.wav /tmp/down3-mod.wav")
 
-run("sox /tmp/down3-mod.wav -b 24 /tmp/down3-norm.wav treble -3 10000 norm -22");
+run("sox /tmp/down3-mod.wav -b 24 /tmp/down3-norm.wav treble -3 10000 norm -32");
 
 run("amixer --card 3 cset numid=3,iface=MIXER,name='UMC1820 Output Playback Volume' 127,127,127,127,127,127,127,127,122,122,122,122,122,122,122,122")
 run("amixer --card 3 cset numid=1,iface=MIXER,name='UMC1820 Output Playback Switch' on,on,on,on,on,on,on,on,on,on,on,on,on,on,on,on")

speaker_experiments/revolve.cc

@@ -92,6 +92,19 @@ struct Rotator {
     rot[2] += windowM1 * rot[1];
     rot[3] += windowM1 * rot[2];
   }
+  void GetTriplet(std::complex<double> right_rot,
+                  std::complex<double> left_rot,
+                  double &right,
+                  double &center,
+                  double &left) {
+    auto ave = 0.5 * (right_rot + left_rot);
+    center = rot[0].real() * ave.real() + rot[0].imag() * ave.imag();
+
+    right_rot -= ave;
+    left_rot -= ave;
+    right = rot[0].real() * right_rot.real() + rot[0].imag() * right_rot.imag();
+    left = rot[0].real() * left_rot.real() + rot[0].imag() * left_rot.imag();
+  }
   double GetSample() const {
     return rot[0].real() * rot[3].real() + rot[0].imag() * rot[3].imag();
   }
@@ -184,12 +197,18 @@ void Process(
                                          assumed_distance_to_line * assumed_distance_to_line);
         float dist_ratio = distance_to_virtual * (1.0f / assumed_distance_to_line);
         float index = static_cast<float>(subspeaker_index);
-        const double sample = .5f * (rot_left[rot].GetSample() +
-                                     rot_right[rot].GetSample());
+        double right, center, left;
+        rot_left[rot].GetTriplet(rot_right[rot].rot[3], rot_left[rot].rot[3], right, center, left);
+        float speaker_offset_left = (2 - 7.5) * 0.1;
+        float speaker_offset_right = (13 - 7.5) * 0.1;
         for (int kk = 0; kk < 16; ++kk) {
           float speaker_offset = (kk - 7.5) * 0.1;
           output[i * output_channels + kk] +=
-              AngleEffect(speaker_offset + distance_from_center, assumed_distance_to_line) * sample;
+              AngleEffect(speaker_offset + distance_from_center, assumed_distance_to_line) * center;
+          output[i * output_channels + kk] +=
+              AngleEffect(speaker_offset - speaker_offset_right, assumed_distance_to_line) * right;
+          output[i * output_channels + kk] +=
+              AngleEffect(speaker_offset - speaker_offset_left, assumed_distance_to_line) * left;
         }
       }
     }