DACS General Meeting
Meeting Review:
July 2011—Convert your LPs and/or tapes to CDs and/or MP3s
and while we are at it … restore audio quality by editing out defects

By Andy Woodruff

At our July 2011 general meeting, Bruce Preston demonstrated how to convert music recordings from old analog formats such as LP’s to current digital formats such as CDs and MP3s.

Bruce began his presentation with descriptions of how music is stored on old and current media.  He discussed the basic legal issues involved with converting music recordings  and explained some necessary terminology and theory.  For instance, he described the unique frequency equalization curve that was applied by convention to the analog files recorded on all LP’s and explained that this equalization curve must be reversed when the file is placed on modern digital media.

Bruce recommended the following free software:

• Audacity, for audio recording and editing.  Available from http://audacity.sourceforge.net/.
• Lame MP3 Encoder, for converting digital files to mp3 files.  Lame is a library for Audacity, and it is explained at http://audacity.sourceforge.net/help/faq?s=install&item=lame-mp3.
• DeepBurner, for CD burning.  Available at http://www.deepburner.com/?r=download.

Bruce showed us sample cables and hardware needed to connect LP record player to a computer.    He demonstrated the use of Audacity to record a computer audio file from an LP.  He explained that the audio gain must be adjusted so that the signal never reaches the maximum allowable audio level, and he demonstrated the effect if it does reach this level.

Bruce also  talked about how one can use Audacity to edit an audio file.  Editing an audio file is similar to editing a word processing file, in that one can modify the contents of the file.  Bruce edited a file that had come from an LP, cleaned up the file by removing static, and  modified its duration.

After Bruce recorded and edited these sample files, he explained that one can burn the resulting audio tracks directly to a CD or compact the file to an MP3 file and then store it as a digital file.  He showed how one can use the Lame MP3 Encoder to create the MP3.

In answer to a question, Bruce explained that the audio voltage level from speaker wires is too high for connection directly to the audio input jack of a computer.  Rob Limbaugh wrote an article, in our dacs.doc newsletter in 2008, regarding conversion of the speaker voltage levels to the appropriate level for computer input jacks.  This article is available here.

Editor’s Note:  This presentation was the first of a series regarding audio recording and editing.  The second installment, scheduled for the November general meeting, will cover live audio recording and multi-track editing.  The third installment, later in November, will be a hands-on workshop.