To Pass Or Not To Pass
- Chirag Kotak (Sonik-Tec)
- Dec 4, 2015
- 4 min read
Sonik Dimensions - To Pass or Not to Pass
‘Filter' - The very word suggests, a sort of selective permittance. On one hand it means
'to keep Out of' and on the other, it could mean 'to allow in'. The process of Filtration is based on certain, specific criteria. If what is to be filtered, fulfils the criterion in question, then it is either allowed to permeate and pass through or, it is prevented from passing at all .The process serves to separate, a part from the whole, whether or not that part is what we would like to keep or, otherwise what we could choose to discard.
'Filters' are the devices used in the filtration process. We use filters in all sorts of applications. Ranging from, the purification of water to make it drinkable, The cleansing of breathable Air through our Air-conditioners, to the preparation of, a cup of Tea or Coffee, in order to separate out the undesirable residue from the desired beverage. In-fact We even unconsciously filter, an enormous portion of the sensory information that our Brains are Bombarded with, on a day to day basis . If We did not, we would be, perpetually overwhelmed by the sheer magnitude of it all.
Filters are also used extensively in the production of Electronic Music.
In the previous article ( An Introduction To Synthesizers ), We briefly touched upon the subject of 'Filters', as one of the tools, used in the shaping of Tones, into more musically useful and pleasing sounds. There are different kinds of filters that are utilized and they yield very differing results. Filters are usually a part of Synthesizers, but can also be standalone units. In Order to Understand what the filters are actually doing, You will need a little Background information about Sound itself.
Having understood that, we can now, better understand what a Filter does. A Filter is a tool that deals with and affects ‘Frequency’. It is used to alter the Harmonic content of a Sound. It alters the sound by either allowing or preventing a part of the sound's harmonic content from being audible. It allows a portion of the sounds harmonic content to either Pass through and be heard or, prevents it from passing, in effect cutting it out.
This is an image of a 50 Hz sawtooth wave viewed on a Spectrum Analyzer. The Harmonics are multiples of the 50 Hz Fundamental frequency - 100 Hz, 150 Hz, 200 Hz, 250 Hz, 300 Hz etc...
We could have a filter that, only cuts out the upper harmonic content of a sound. Such a filter is called a ‘High Cut’ or alternatively a ‘Low Pass’ Filter. It allows the Fundamental frequency and the lower harmonics to be Heard (Pass) while cutting out the Higher Harmonics . The point after which the frequencies are cut, is called the ‘Filter Cutoff Frequency’. This Point can be shifted anywhere in the 20 Hz to 20kHz spectrum, cutting off all the content Above/ After it.
Similarly we have a ‘Low cut’ or ‘ High Pass’ filter. As the name suggests, this filter cuts off all the content Below/ Before the Cutoff frequency and allows all the content above it to pass through.
We also have a Band Pass Filter. This sort of Filter allows only a narrow band of harmonics/ frequencies to pass through, cutting off all the content on either side of the band. The width of the band can be narrowed or widened and the band can be shifted to any part of the spectrum.
Lastly We have a Band Stop/ Notch Filter. This sort of Filter cuts out a narrow band of content like a notch and allows all the content on either side of the band to pass through, unaffected. The Width of the Notch can be narrowed or widened and the notch can be shifted to any part of the spectrum.
These are the types of filters that are commonly used in the production of Electronic music. They can be used for either creative or corrective purposes.As a corrective tool they can be used to make space ‘In The Mix’, for other sounds and instruments, so that many instruments can fit well together without their frequencies clashing and fighting. Equalizers are used for this purpose and are made up of various filters.
Creatively, filters can be combined with other parts of a Synthesizer, like Envelopes, LFO's, and Step sequencers, to offer the producer, numerous ways to modify, morph and evolve sounds and instruments.
Filters have contributed towards Electronic Music sounding the way it does. Modern Music production techniques would not be possible without Filters and all the benefits and utility they provide.
I hope You enjoyed delving further into the world of Electronic Music. If You would like to Know more about Filters, Please follow the Links provided Below.
Also Feel free to comment or write in with any questions. Thanks for reading !
Author : Chirag Kotak
Sonik-Tec Electronic Music Production Courses , Mumbai
www.soniktec.com, Sonik-Tec’s Facebook Page Email: soniktec@gmail.com
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