fig, ax = plt.subplots(1, 2, sharex=True, sharey=True)
f, t, Sxx = signal.spectrogram(x, fs=fs, window='hann', nperseg=8192,
                               scaling='spectrum')
mx = np.abs(10 * np.log10(Sxx)).max()
ax[0].pcolormesh(t, f / 1000, 10 * np.log10(Sxx), shading='gouraud',
                 vmin=-mx, vmax=0)

f_1, t_1, Sxx_1 = signal.spectrogram(x1, fs=fs, window='hann', nperseg=8192,
                                     scaling='spectrum')
ax[1].pcolormesh(t_1, f_1 / 1000, 10 * np.log10(Sxx_1), shading='gouraud',
                 vmin=-mx, vmax=0)