Now that we have become habituated to clean sound and to the easy to use of digital recordings, we have relegated to the forget those LP that we have saved for years. We are no longer so tolerant to these flaws, proper of vinyl records or having to clean up the disk before and after listening. But now that we have decided to deal by our own of the restoration of these recordings that are no longer in the market, let us do it by a methodical way that ensures us an optimal outcome.
Stage 2: Click and pop elimination.
As we have already completed the first stage and we have the recording digitized in WAV format, in the next steps we will move purely in the digital domain. The imperfections of audio that we have to correct to give new life to recordings are as follows:
Clicks, pops and scratches: In the slang of audio, clicks are small mild impulses, as click this site the crackling of the firewood, product of the static on the disk and of small particles of dirt. The pops are a problem something more serious and more difficult to correct and relate to the scratches on the surface that distorted the groove or any particle embedded deeply. They cover the entire audible frequency range. The scratches are bigger damages widespread on the surface of the disk and are difficult to remove.
Background Noise: Or surface noise, It is the noise produced by the friction of the stylus moving in the groove. The quality of vinyl is very important. If the vinyl is of good quality, virtually there will be no background noise and we would only hear the “Hiss” of the master recording tape. This noise covers the whole audible spectrum but is most noticeable in the higher frequencies and in the softer passages of the music.
Rumble: Corresponds gangstar vegas cheats tool to the mechanical noise of the turntable, transmitted to the phonographic cartridge. It is a low frequency noise of less than 60Hz.
Hum: Noise that is strained from the power source of the sound equipment or during recording and it corresponds to the fundamental of 50 or 60Hz and their harmonics.
Hiss: Is the background noise of tape recording. It is a constant noise and easy to eliminate.
Equalization: Restitution of the lost frequencies due to the process of noise reduction and hiss suppression. It is also recommended to generate harmonics for correcting this problem.
Dynamic Range: Due to the limitations product of the combination of background noise of the disk and the saturation of tape recording in the study, the music in the LP was compressed to fit the range of 60dB. The sound level was lowered in the stronger passages and increased in the softer ones. This problem does not exist in digital recording which has a dynamic range greater than 90dB.
It is desirable to focus the process in the suggested order because that will aid the identification and the solution of each problem.
The clicks and pops can be a genuine distaste for the music lover. They can ruin a good interpretation because we tend to pay more attention to the imperfections than to the work. There are many filters that remove them automatically adjusting the sensitivity, the threshold and using algorithms that discriminate according to the level and the type of the background noise. But if we want a professional result we must set aside of the fully automated options. Each LP is a variations of the same problem and it should be analyzed in a particular form. It is necessary to hear and “see” the clicks and pops to check here totally eliminate them.
Of all the software I tested in this regard, the more indicated is Adobe Audition 3, which includes an excellent click remover module and it also allows us, literally, see the noise. This program is not cheap, but its quality and versatility fully justify its price. If you are skeptical about acquiring this program, you can download it for free from the Adobe’s site and try it for a month. I guarantee you that before the end of the trial period you will purchase the original version.
The manner for proceeding to eliminate these annoying impulses, once uploaded the file, is to change the view to Spectral Frequency Display. In this way, we will see in the X axis the time, in the Y axis the frequency and the magnitude of the sound will be indicated by the color. The clear colors corresponds to strong intensities of sound and the darker colors weak sounds. Adjust the Spectral Frequency Display to show a range about 100dB and select the logarithmic mode that is the natural way to “see” the amplitude of the sound. Then adjust the zoom on the main window for covering about 10 seconds of time reproduction. In this way, the clicks and pops will be clearly visible. Now a last and important visual adjustment: Apply Reverse to the Spectral Frequency Display to see in inverse video mode. In this way the music with stronger volume levels will be dark, i.e. it will disappear, and it will become clear and bright the low intensity of sound, i.e. the noise.
With these settings we can begin our process of click and pop elimination. With the selection tool highlight about 10 seconds of the file where the clicks are more widespread and clearly audible. Use the tool “Click/Pop Eliminator” using the first option “Auto Find Levels”. Listen carefully to the fragment corrected and compare it to the adjacent music that has not been processed. It is not the goal to make disappear all defects but we must ensure that the almost all of them will be eliminated, with the exception of the largest, without noticing a deterioration of the sound or some collateral effects. If you are not satisfied with what you obtained then implement “Undo” and repeat the process changing the settings of the threshold level, sensitivity, discrimination, etc. Once you have reached the goal, “Undo” this last action for the test fragment and implement this filter to the whole archive. Now that we have eliminated almost all of the clicks and pops, we must keep the file with another name, such as putting the suffix “_CLICKS00” or something like that. You should never overwrite the original file because it is possible that later you want redo this step and, and without this exception, you may not do so.
The final part of the process for click elimination, it is the slowest one, because you have to listen carefully to the complete file. With the settings from the previous step listening to the music program until you find the first pop that was not removed due to its size. You will see clearly the impulse showed up on the screen. With the selection tool, surrounding it perfectly, apply “Click/Pop Eliminator” but now using the option of the bottom of the window: “Fill Single click Now”. Repeat this process for the entire file.
It is important to note that it should not be convenient to apply a noise reduction filter before having eliminated all the clicks because, in some circumstances, it should be to generate a certain type of echo that is difficult to detect and remove.
Finally, with dedication and patience and, monitoring the complete file, we can eliminate all these singularities without affecting the musical program. This is a great help in the restoration of an LP because now you will hear only a uniform noise that will be easier to detect and remove.