Mittwoch, 11. September 2019

Coasta Cordalis, restoration of analog master tapes and and single vinyls


An employee of Bellaphon Records has dived into the archive to retrieve old audios of Costa Cordalis and daylight. He came with the 1/4 "masterband of his first album "Folkolore Aus Aller Welt" from 1966 and some vinyl singles.
This material now had to be digitized and, if necessary, worked up.
To my astonishment was the sound that came from the 1/4 "band very well, the sound was stereo and there was almost no noise to hear. The entire album was only produced with two acoustic guitars and a lead vocal. With the pegeltone I fixed the azimuth of the machine heads. Then I set the recording level so that the loudest passages were about -10 to -6dB. In total, there should be 13 tracks on the album. To my surprise, there was a bonus track, which was refereed and additional announcements to the individual titles in the appropriate languages ​​of the songs. These takes were played at the end of the tape. I bounced them together after the digitization to the individual songs. In a particular title, the noise in Intro was a bit strong, so at the request of Bellaphon, I ran away from the section in question. For this job I have several tools of iZotope (RX7) and Steinberg available. 
De-noiseing is generally about reducing noise without affecting the sound of the music. My plug-in is available with the Voxengo Gliss Equalizer in combination with a dynamic equalizer. Both components have intervened very little in the program. Adding both tools quickly stopped the noise without affecting the amount of music.

Much more complex was the challenge of optimizing the sound of old single-vinyl records.
 Here was a whole range of imperfections to work on. The sound was mono, contained plenty of disk crackers and sometimes quite unsightly distortions. First of all, I played the vinyls (dry) as they were. When digitizing it was only about the plates properly in an appropriate level to play in the calculator. Again, I kept the level at -10 dB to -6dB. Also for eliminating the cracker software from Wavelab and IZotope is available. Here the RX 7 worked very well. The cracker I could eliminate it. However, it was necessary to individually identify and mark each cracker and calculate or render with the correct threshhold. If I chose the section too long, because two crackers were relatively close to each other, then the tool "killed" the punch of the snare drum because it considered the transients of the drum to be a crackpot.The RX 7 was also able to eliminate distortion on some passages because it has kept the distortion over transients. This worked very well on some passages, in other places a more specific solution was needed. 

I experimented with a multiband compressor in combination with a de-esser. Distortion in most cases affected the voice in the frequency range between 2000 Hz and 4000 Hz. With the compressor, I reduced the critical frequency range by about 2-3 dB. It turned out, however, that this reduction was not enough on the one hand, but on the other hand, with a greater reduction, the voice became noticeably too quiet. Therefore, I did additionally with the de-esser very selectively reduced the tearing frequency. This narrowband processing allowed me a further reduction of 2 to 3 dB. Once again, I've found that a plug-in for a specific application does almost miracles, but does not provide a usable result for another problems. In any case, it is necessary to deal with the matter exactly. Simple "plug and play" tends to destroy the program rather than achieving a good result. I am amazed at what is now possible with modern software.

Stefan Noltemeyer