can I use this software to alter the db of a mp3 to 17.3 if not can anyone suggest a way of doing this
Yes but you may not want to. Audacity doesn’t edit MP3. It imports MP3 into its own high-quality format and then makes a new MP3 when it’s done. So you get double the compression damage.
Import the track and then:
Effect > Amplify > put -17.3 in the top box > OK.
Audacity will reduce the loudness of the show by 17.3 dB.
File > Export MP3. You may need to install the “lame” software to create an MP3.
http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#lame
Koz
The maximum amplitude of an audio signal is 0 dB.
Audio signals are measured “below” 0 dB and are therefore negative values.
What exactly are you trying to do (and why)?
Do you want an average of -17.3, or a peak of -17.3? -17.3dB could be a typical average level, but it’s really low for a peak level… There is a plug-in called stats.ny if you want to find the average, or you may want to use a 3rd-party tool.
With MP3, I’m not sure if you can hit the “point 3” exactly, especially if you are talking about the peaks. MP3 is lossy compression, which means you don’t get-out exactly what you put-in… The MP3 compression process generally makes some peaks higher and some peaks lower. (With a high-quality setting, you shouldn’t hear the difference, but you can measure it.)