Also, a phono pre-amp will apply EQ (the RIAA curve) to correct for the settings applied to the signal at the time of recording. At the time of recording, much of the low end was attenuated from the recording in order to prevent wide swings in the stylus that would have necessitated spacing the grooves too far apart to get much useful recording time on a disk. This EQ must be reversed upon playback to restore the full EQ spectrum.