The input signal gets attenuated significantly for the voltage in the diode bridge to be kept within limits. The input signal has to be attenuated by 40 dB so that the voltage stays within the linear transfer curve. This results in a very high noise floor, which is probably the main disadvantage with diode bridge compressors. This 40 dB of input attenuation eventually gets restored in the makeup gain section. These extreme levels of attenuation and recovery make diode bridge compressors quite noisy. That being said, as the sophistication of electronic circuits has grown over the decades, diode bridge compressors have become much quieter than they used to be. While not exactly a disadvantage, the diode bridge compression circuit is non-linear, meaning that the amount of compression applied to the signal is not consistent across the entire frequency spectrum. This leads to uneven compression and distortion of the audio, which has come to be recognised as the diode-bridge sound.