batgirl
Newbie
Joined: 05 Apr 2005
Posts: 6
|
| easy qustion but i am stuck what is filter modulation?? |
 |
|
ok can someone in simple words tell me what filter modulation is.... i went to various sites and it tells me how to set these values but i dont know what it means... can someone expain it to me in simple english and tell me what it means when we set a "To Filter Cutoff" value to say 1000 in a LFO filter modulator for a sound font...
PLEASE HELP!!!!
thanks allot |
Tue Apr 19, 2005 6:47 pm |
|
|
AMR
Joined: 16 Sep 2003
Posts: 58
|
| Re: easy qustion but i am stuck what is filter modulation?? |
|
|
quote:
Originally posted by batgirl
ok can someone in simple words tell me what filter modulation is.... i went to various sites and it tells me how to set these values but i dont know what it means... can someone expain it to me in simple english and tell me what it means when we set a "To Filter Cutoff" value to say 1000 in a LFO filter modulator for a sound font...
PLEASE HELP!!!!
thanks allot
A filter is like an equalizer, you enhance or cut a certain range of frequencies... like lowering treble on your hifi set, you are "modulating" the "treble filter" downwards, "cutting off" the treble... it's a very broad definition and a quite arguable on its simplistic aproach, but you wanted plain english...
An LFO is a "Low Frequency Oscilator" which means it does the same as you moving the treble (or whatever filter) up and down really slow. So instead of you being the "modulator", the LFO does it for you.
"Cuttoff" is usually a "low pass" filter, much like "treble", it lets everything pass in maximum setting and starts "cutting off" (filtering) as you "modulate" it (rotate the knob to make it simple), cutting treble and leaving you with just more and more "bass" and less "bright" as you modulate into the "further more" knob direction...
You can however "modulate" in whatever direction you want. as fast/slow as you want (cut, dont cut... cut a little slowly now... cut a lot in an instant... I hope you get the point).
Kind Regards,
AMR
http://www.alvaromrocha.com
|
|
Tue Apr 19, 2005 8:32 pm |
|
|
|
|
Michael_S
Eager Beaver
Joined: 10 Apr 2005
Posts: 16
|
|
|
|
You're right, it's difficult to find explanations in plain English sometimes. I would like to add a little to the above comments.
In my mind LFO is composed of two entites. first is the filter. in this case a low pass filter. But for keeping this general, filters come in different forms. So the first thing is to understand ...what is a filter.
A low pass filter will allow low frequencies to pass (high frequencies attenuated), high pass filter allows high frequencies to pass and band pass only allows frequencies in that band to pass. But there are many, many types and the above are the 3 main ones, most others are sub groups.
However there isn't normally an exact frequency where one minute, everything is fine and left untouched, and 1Hz later it is completly attenuated. There is something called a roll off, which makes the filters edge look more like a slope. The cutoff point, is defined at being the point where the signal has been attenuated by 3db (or lost half its power). So the interesting point to note here is. That if you have a low pass filter whose cutoff frequency is 1Khz (fc) . Attenuation has actually begun before 1Khz.
The second part Oscillation I need to come back and add later. But basically like the word suggestes, it means to go back and forth. An effect like Wah Wah can be created by moving the cutoff frequency of your filter, in effect allowing more or less of the signal to pass. |
|
Wed Apr 20, 2005 1:53 am |
|
|
AUdIoCoUrSeS
Joined: 31 Oct 2002
Posts: 2014
|
| Low Frequency Oscillator (LFO) |
|
|
Think of the terms LFO, VCA, VCF, etc as "blocks".
You can use the blocks to make other blocks perfom something.
For example:
Low Frequency Oscillator (LFO)
A VCO (voltage controlled oscillator) can function as a generator of low frequency waves, when it does we call it a LFO. A LFO can then be used in a controlling manner to open and close a VCF (voltage controller filter) at a rate dependant on the generated frequency.
e.g. A sine wave (or any shape waveform) from the VCO (acting as a LFO, say at a rate of 2Hz) could be applied to a VCF (voltage controlled filter). The VCF is then being controlled by a sine wave from the LFO. The filter will open and close at the frequency of the sine wave. 2 times a second for example.
_________________
It's all in the ears. - Learn the concepts not the software.
Audio Courses is a way into the music business for you
|
|
Wed Apr 20, 2005 7:02 am |
|
|
|
|
 
|
|
All times are GMT. The time now is Sat May 17, 2008 5:21 am
|
|
|
|
| |
