Cleaning and noise removal

Cleaning and noise removal

This piece of plastic usually called a record, an album, or an LP (long play) stores information in a physical way. Gramophone needle that follows the groove vibrates according to the shape of the plastic and transfers the vibration to the electric signal which is then reproduced into sound. To obtain a clear sound it is therefore useful to clean your LP every now and then.




For this purpose, to clean the micro dust that has settled into surface, my friend has used a soft cloth. Dust is nothing but small particles, so this method of physically wiping them out is probably the most practical one. Washing a record with water and soap on the other hand, unless you are after a certain greasy spot of dirt, since water won't dissolve dust, is a waste of time.

Cleaning clicks and pops

Sometimes an old and worn out LP, scratched or otherwise damaged, will cause needle to jump and you will hear a short but loud click. This annoying sound can fortunately be digitally removed. Yes, thanks to this click's distinctive shape, it can be recognized and cleaned.


Spot it.


Analyze it. It is short and loud.


Remove the click and at the same time restore the original sound.

Noise removal

Speaking of cleaning certain sound pattern, similar method can be used to remove unwanted background noise. Suppose certain noise pattern is present throughout the whole record. Say this noise consists of many rather silent clicks and pops, since your LP is a very worn out one.


Spot the noise. Usually it can be found between two songs where the silence is supposed to be.
Then analyze it. Audacity can get the noise profile and store this pattern.


Then in step 2 remove it. Noise removal works by mathematically subtracting two curves, so noisy record minus noise pattern is supposed to equal original music as before noise has settled in.

However mathematics is not perfect here, because noise pattern is not perfect to start with. As the noise pattern contains certain shapes that are ever present in original recording as well, it can't possibly be hundred percent isolated. The result is cleaned music that sounds too clean, sounds a little empty as if it lacks color. What happens is certain sounds are being distorted by this process.

Therefore a question is should one apply noise removal at all. Or at least should it be applied to full extent. My friend has an interesting answer to this question. He says: "Leave the noise there. Leave it to nature. Human ear is wondrous apparatus, it will mask the noise, all the subtractions will be done by the brain on the fly and as long as the noise is spread to subsonic and ultrasonic regions, one will enjoy the original sounding music without being too bothered by the noise."