diff --git a/src/backscattering_analyzer/analyzer.py b/src/backscattering_analyzer/analyzer.py
index f18f25d..624de7c 100644
--- a/src/backscattering_analyzer/analyzer.py
+++ b/src/backscattering_analyzer/analyzer.py
@@ -131,19 +131,25 @@ class Analyzer:
         Compute psd of the computed projection with current bench
         excitation
         """
-        result = zeros(
-            len(
-                interpolate_abciss(
-                    (self.movement.psd(), self.coupling[0].abs())
-                )
+        results = zeros(
+            (
+                len(self.coupling),
+                len(
+                    interpolate_abciss(
+                        (self.movement.psd(), self.coupling[0].abs())
+                    )
+                ),
             )
         )
 
         # frequencies depends of psd result, which we do not have yet
-        frequencies = zeros(len(result))
+        frequencies = zeros(results.shape[1])
 
         for index in range(len(self.coupling)):
-            phase = (index + 1) * 4 * pi / (self.settings.wavelength*1e6)
+            phase = (
+                (index + 1) * 4 * pi / (self.settings.wavelength * 1e6)
+                # * 1e6 sinon la courbe n'est plus du tout la même
+            )
 
             factor_n = (self.movement * phase).sin().psd().sqrt()
             coupling_n = self.coupling[0].abs()
@@ -157,14 +163,15 @@ class Analyzer:
             # no need to redefine it each time but simpler here
             frequencies = factor_n.x
 
-            result += (
+            """ # from theoric equation
+            results[index] = (
                 sqrt(self.settings.scattering_factor[index])
                 * self.settings.power_in
                 / self.settings.power_out
                 * (coupling_n * factor_n + coupling_d * factor_d).y
             )
             """
-            result += (
+            results[index] = ( # from matlab
                 sqrt(self.settings.scattering_factor[index])
                 * self.settings.wavelength
                 / (4 * pi)
@@ -172,11 +179,10 @@ class Analyzer:
                 .sqrt()
                 .y
             ) ** 2
-            """
 
         self.projection = Signal(
             frequencies,
-            result,
+            sum(results),
             self.settings,
         )
-        return self.projection
+        return self.projection.sqrt()
diff --git a/src/backscattering_analyzer/settings.py b/src/backscattering_analyzer/settings.py
index 4b11848..e53c07b 100644
--- a/src/backscattering_analyzer/settings.py
+++ b/src/backscattering_analyzer/settings.py
@@ -34,7 +34,7 @@ class Settings:
 
         self.calib_bench = 1.15
         self.calib_mirror = 1.15
-        self.scattering_factor = [1.3e-3, 1e-12]  # parameter to change
+        self.scattering_factor = [1.3e-4, 1e-16]  # parameter to change
         self.vibration_frequency = 0.2
 
         index = 0