Filter.md

+# Filter
+## Basics
+A filter is a circuit which filters out certain parts of the frequency spectrum of the incoming spectrum.
+Filters are named by the spectrum they _cut_ out or _pass_ through:
+- **Lowpass (LP) or Highcut Filter** – cuts away the high frequencies, leaves the low ones
+- **Highpass (HP) or Lowcut Filter** – cuts away the low frequencies, leaves the high ones
+- **Bandpass (BP)** – a combination of LP and HP – leaves stuff around the cuttof frequency, cuts away higher and lower frequencies
+- **Notch** – the inverse of a BP – cuts away stuff around the cutoff frequency, leaves the higher and lower frequencies
+- **Comb Filter** – Nomen est omen
+- ...
+
+![Different Types of Filters](http://modular.atoav.com/x/Filter_types.png)
+
+Every filter typically has a well defined Cutoff Frequency – this is the area around which the Filter starts to act.  
+Sometimes this area is higher than the rest, this is called "Resonance":  
+![Different Types of Filters](http://modular.atoav.com/x/Filter_types_resonant.png)
+
+## Filters
+There are many different ways to build a filter, each with its own unique character.  
+See the Doepfer A-124 Wasp Filter in [this youtube video](https://www.youtube.com/watch?v=A-ZTgWFzDM8)   
+See the Doepfer A-106-5 SEM Filter in [this youtube video](https://www.youtube.com/watch?v=4pZDcn6qNn8)   
+See the Polivoks VCF in [this youtube video](https://youtu.be/Q5pOU6YaDa0?t=135)
+