diff --git a/lasp/filter/soundpressureweighting.py b/lasp/filter/soundpressureweighting.py
index e2cd072..93a4dd0 100644
--- a/lasp/filter/soundpressureweighting.py
+++ b/lasp/filter/soundpressureweighting.py
@@ -136,29 +136,57 @@ class SPLFilterDesigner:
         z, p, k = bilinear_zpk(zeros_analog, poles_analog, k_analog, fs)
         sos = zpk2sos(z, p, k)
         return sos
+        # return z, p, k
+        # return zeros_analog, poles_analog, k_analog
 
-    def A_Sos_design(self, fs):
-        """
-        Create filter coefficients of the A-weighting filter. Uses the bilinear
-        transform to convert the analog filter to a digital one.
+def show_Afir():
+    from asceefig.plot import Figure
 
-        Args:
-            fs: Sampling frequency [Hz]
+    fs = 48000.
+    freq_design = np.linspace(0, 17e3, 3000)
+    freq_design[-1] = fs/2
+    amp_design = A(freq_design)
+    amp_design[-1] = 0.
+    firs = []
 
-        Returns:
-            Sos: Second order sections
-        """
-        # Poles of A-filter 
-        p1 = 2*np.pi*self.f1
-        p2 = 2*np.pi*self.f2
-        p3 = 2*np.pi*self.f3
-        p4 = 2*np.pi*self.f4
+    # firs.append(arbitrary_fir_design(fs,L,freq_design,amp_design,window='hamming'))
+    # firs.append(arbitrary_fir_design(fs,L,freq_design,amp_design,window='hann'))
+    firs.append(A_fir_design())
+    # from scipy.signal import iirdesign
+    # b,a = iirdesign()
+    freq_check = np.logspace(0, np.log10(fs/2), 5000)
+    f = Figure()
 
-        zeros_analog = [0,0,0,0]
-        poles_analog = [p1, p1, p2, p3, p4, p4]
-        k_analog = p4**2/self._A_uncor(self.fr)
+    f.semilogx(freq_check, 20*np.log10(A(freq_check)))
+    for fir in firs:
+        H = freqResponse(fs, freq_check, fir)
+        f.plot(freq_check, 20*np.log10(np.abs(H)))
 
-        z, p, k = bilinear_zpk(zeros_analog, poles_analog, k_analog, fs)
-        sos = zpk2sos(z, p, k)
-        return sos
+    f.fig.get_axes()[0].set_ylim(-75, 3)
+
+
+def show_Cfir():
+    from asceefig.plot import Figure
+
+    fs = 48000.
+    freq_design = np.linspace(0, 17e3, 3000)
+    freq_design[-1] = fs/2
+    amp_design = C(freq_design)
+    amp_design[-1] = 0.
+    firs = []
+
+    # firs.append(arbitrary_fir_design(fs,L,freq_design,amp_design,window='hamming'))
+    # firs.append(arbitrary_fir_design(fs,L,freq_design,amp_design,window='hann'))
+    firs.append(C_fir_design())
+    # from scipy.signal import iirdesign
+    # b,a = iirdesign()
+    freq_check = np.logspace(0, np.log10(fs/2), 5000)
+    f = Figure()
+
+    f.semilogx(freq_check, 20*np.log10(C(freq_check)))
+    for fir in firs:
+        H = freqResponse(fs, freq_check, fir)
+        f.plot(freq_check, 20*np.log10(np.abs(H)))
+
+    f.fig.get_axes()[0].set_ylim(-30, 1)