Most modern recordings are put together in the recording studio using many tracks. A track can be something played by a guitar player....or a piano player....or the singing by a lead vocalist....etc. All these tracks can get EQ'ed, compressed, re-recorded, before being combined (or mixed) into a 2 track stereo mix, to be mastered for release on CD, vinyl record, downloads, etc. The final 2 channel stereo mix may be a combination of tracks recorded in many different recording studios, engineered by different recording engineers, over many months (or years), etc. Sometimes a 2 track stereo mix may go through another remastering for release on a specific format, for example, vinyl record. So there is not really a 原錄音.