I’ve been experimenting with techniques to remaster older recorded music, and I believe I have found an approach that can make older recorded music sound brand new. It works very well on live recordings, music video tracks, and can make any audio with reduced treble or bass sound very rich, and restore the overall sound dynamics. I’ve worked out a reliable procedure to follow.
1) first step is to take your recording and do any musical corrections, such as if its a vinyl recording to adjust each stereo track for balanced sound, remove or reduce the clicks, scratches, rumbles, etc. If its a tape recording, correct for any tape level volume drops or other sound glitches. Save the final file as the AUP project and identify it as the sound corrected version. In some cases you will need to do some more sound corrections later as the other processes develop, so also save the project as a backup .FLAC file, and I found its easier to use the FLAC file for your work in progress.
2) With the sound corrected .FLAC file, copy and past the sound to a second audio track. Play both together (Don’t change the alignment) and if necessary, reduce the tracks Gain so no clipping occurs in the VU meters. This is just double tracking the sound, however it boosts the vocal range, boosts the sound dynamics, and boosts the overall ambiance without using amplification.
2a) Some additional options for this, depending on the type of music, such as classical, there is no musical sound above 12kHz, so you can reduce the overall noise hiss of the track by running the High Pass and Low Pass filters. You can also eliminate all but the vocal range by selecting 300Hz as the High Pass cut off and 3000Hz as the Low Pass cut off. You can also boost a particular instrument by adding another track with only that instruments frequency range. So long as the sound output does not clip, use the tracks Gain to adjust the volumes to your liking. Save again as a .FLAC file, export and re-import that file.
Note: If an instrument sounds distorted such as drum machines or symbol crashes, you have selected a frequency range that cuts into the sound. Just undo the effect and select a wider frequency range.
2b) adding some minor echo to a live recording can greatly increase its sound dynamics by adjusting the Echo or Reverb effects, although that is a little too much detail to add now, this stage is where it would be added.
Note: These next steps you want to run back to back. After a few tries it will become fast and easy. There is not much point in listening to the song in between these steps, go through steps 3 to 7 and listen to the song at the end.
3) Next is the equalization corrections. Use the Equalizer to adjust the Bass and Treble to your liking, or whatever sounds rich or realistic to you. Human hearing can detect the lows and highs much more easily, but is not too particular to the midrange. Equalization boosting the extreme’s is done for two reasons, it restores the sound dynamics to the bass and treble. The midrange was boosted by the previous step of double tracking. If we just boosted the bass, treble and midrange with the equalizer, there would be lots more noise and not much difference in overall sound quality.
Sound engineers purposely reduce the frequency range and sound dynamics of the recorded music using limiters, so the equipment of the day (such as record and tape players) could play the music without distorting the music. Microphones, and to a degree their placement don’t record bass sounds very well, so this is also why we have to boost the lower frequency ranges to get the sound back to its original rich state.
After the equalization boost is applied, the waveform levels will be out of range, don’t panic! Normally if the waveforms go out of range you have lost audio information, but in this case its a mathematical calculation and Audacity will correct for this in the next step.
4) Next click on Amplify, and Audacity will give you a negative number, click Ok and the audio will be reduced so all waveforms fall within range.
5) Next use Hard Limiter to increase the overall sound level. The purpose of Hard Limiter is to make a definite stop point so that no audio will go above a set decibel level. Musically it does not alter the sound or make any difference in the individual waveforms volume level. For example, if the average waveform level of the song is at -5db, and only a few waveforms are at maximum peak, setting the Hard Limiter to -4db will reduce all the songs waveforms so that none exceed -4db.
6) Next run the Compressor effect. This will really make the song pop! I use it at the minimum effect level, with Threshold and Noise Floor set to -20. Ratio 1.5:1, Attack Time .01secs, and Release 3 secs.
I have the two bottom boxes clicked to Make up Gain for 0db after compressing, and only compress the peaks.
A bonus feature of Compressor is it won’t cause clipping, so it will increase the volume of the quieter parts, but won’t cause the loud waveforms to go out of range.
7) Lastly I run Hard Limiter again to reduce the waveforms to -.5db so that there is some clearance headroom in the final output file so it can be exported to other programs without clipping.
When you listen to it at this point, if the Base or Treble sound is too much, or just not to your liking you can just click on Undo, right back to the start of the Equalization effect and make corrections to your equalization curve. Also this process may uncover some other deficiencies in the audio quality. Songs that you once thought were audio quality perfect, this will reveal any shortcomings it may have, so make note of it and go back to the original and make some further corrections. Background sounds that were once hidden will also be revealed with this technique.
All magnetic tape recording media had some areas of audio volume dropout, or buzz noises from electronic sources. In many cases I’ve had to go back to the original AUP file and re-correct it many times before I was happy with some songs. Overall, I have not found one song that this technique won’t improve to some degree.
8) Lastly, export to your favorite listening format.
I have put a few songs remastered with this technique on youtube.
Some 1970’s through 1980’s studio music;
Bette Midler - The Rose
Joey Scarbury - Believe it or not
Roedelius - Pink Blue & Amber.
James Johnson plays Bach (BWV532)
Zebra - Time and Who’s behind the door.
Note:WMG already had these two songs muted so USA listeners will have to use Hola to hear it.
I’ve also redone some video soundtracks for the band Spoons, Walk the Plank and Hands of Money.
I also have other songs re-edited or remixed with Audacity posted, all with appropriate info on copyrights, derived work and remixing legalities.
On new recordings, this technique does not add much, except for the compressor effect adds to the background dynamics, sometimes a little too much. Sometimes on newer recordings I found its better to leave the compressor stage out and use the amplify effect for some minor volume boosting. There is no reason why this technique won’t work or improve new creations, not just on commercial music.