Editing Phonograph record (section)

===Sound fidelity===
At the time of the introduction of the [[compact disc]] (CD) in 1982, the stereo LP pressed in vinyl continued to suffer from a variety of limitations:

The stereo image was not made up of fully discrete left and right channels; each channel's signal coming out of the cartridge contained a small amount of the signal from the other channel, with more crosstalk at higher frequencies. High-quality disc cutting equipment was capable of making a master disc with 30–40&nbsp;dB of stereo separation at 1,000&nbsp;Hz, but the playback cartridges had lesser performance of about 20 to 30&nbsp;dB of separation at 1000&nbsp;Hz, with separation decreasing as frequency increased, such that at 12&nbsp;kHz the separation was about 10–15&nbsp;dB.<ref>{{cite book |title=Handbook for Sound Engineers: The New Audio Cyclopedia |url=https://archive.org/details/handbookforsound00ball_195 |url-access=limited |last=Alexandrovich |first=George |editor=Glen Ballou |chapter=Disc Recording and Playback |pages=[https://archive.org/details/handbookforsound00ball_195/page/n888 873]–882, 897 |publisher=Howard W. Sams & Company |year=1987 |isbn=0-672-21983-2}}</ref> A common modern view is that stereo isolation must be higher than this to achieve a proper stereo soundstage. However, in the 1950s the [[BBC]] determined in a series of tests that only 20–25&nbsp;dB is required for the impression of full stereo separation.<ref>{{cite book |url=https://books.google.com/books?id=PvKPEFu2PVkC&pg=PA254 |page=254 |last=Self |first=Douglas |title=Small Signal Audio Design |publisher=Taylor & Francis |year=2002 |isbn=0240521773 |url-status=live |archive-url=https://web.archive.org/web/20160624184131/https://books.google.com/books?id=PvKPEFu2PVkC&pg=PA254 |archive-date=24 June 2016 }}</ref>

Thin, closely spaced spiral grooves that allow for increased playing time on a {{frac|33|1|3}}&nbsp;rpm microgroove LP lead to a tinny pre-echo warning of upcoming loud sounds. The cutting stylus unavoidably transfers some of the subsequent groove wall's impulse signal into the previous groove wall. It is discernible by some listeners throughout certain recordings, but a quiet passage followed by a loud sound allows anyone to hear a faint pre-echo of the loud sound occurring 1.8 seconds ahead of time.<ref>{{cite web|url=http://audacityteam.org/forum/viewtopic.php?f=26&t=102&start=0&st=0&sk=t&sd=a&view=print |title=Audacity Team Forum: Pre-echo when recording vinyl record |publisher=Audacityteam.org |access-date=26 September 2012 |url-status=dead |archive-url=https://web.archive.org/web/20090609184049/http://audacityteam.org/forum/viewtopic.php?f=26&t=102&start=0&st=0&sk=t&sd=a&view=print |archive-date=9 June 2009 }}</ref>