Filters

• 1). There are three basic types of filters: high pass(HPF), low pass (LPF) and band pass (BPF). An HPF only allows high frequencies to pass through the filter, while and LPF only allows low frequencies. BPFs are adjustable and create a bell-shaped filter that, for example, might only allow the frequencies between 300Hz and 3,000Hz to pass through. Sometimes filter types are accompanied by a measure of gain, such as 6dB, 12dB or 24dB. This indicates how many decibels the frequency will be reduced as the filter curves pass over it.
  
  
• 2). Filters generally have two settings: Cutoff and Resonance.
  Cutoff is the setting that determines the frequency curve and at which frequency the filter will process sound. The values of the Cutoff knob are measured from 0 to 127 and, therefore, do not match individual frequencies, since the human ear generally senses frequencies between 20Hz and 20,000Hz.
  Resonance is the setting that determines the amplification of the cutoff curve. It is used to achieve "squelchy" effects, as the frequency curve passes through the frequency spectrum.
  To use a filter, follow the next four steps.
  
  
• 3). Find the filter section on your keyboard, synthesizer or VST and turn it on, if it has an on/off switch.
  
  
• 4). Select what kind of filter you want to apply (HPF, LPF or BPF).
  
  
• 5). Adjust the Cutoff knob until you reach the frequency you want to process.
  
  
• 6). Adjust the Resonance knob up and down until you achieve the effect you want.
  
  

Envelopes

• 1). The most common type of envelope is an Attack-Decay-Sustain-Release (ADSR) envelope. Other types of envelopes include ADR (Attack-Decay-Release) and ADHR (Attack-Decay-Hold-Release).
  
  
• 2). An envelope determines the shape of a waveform over time. The Attack setting tells the amplifier how fast it can reach full volume once a key is held down. Decay decides how long it takes for the amplifier to drop from full volume to sustain volume. Sustain means "to keep from falling," and this setting determines the constant volume of the patch or sound for as long as the key is held down. The fade-out of the sound over a length of time is determined by the Release setting.
  
  
• 3). To create an envelope that makes a sound achieve instant full volume with a short decay to constant volume and a quick fade out you would set your ADSR settings as follows.
  
  
• 4). Set your Attack knob to zero (0).
  
  
• 5). Set your Decay knob somewhere between 0 and 64.
  
  
• 6). Set your Sustain knob to 64.
  
  
• 7). Set your Release knob between 0 and 32.
  
  
• 8). Press a key and hear how your envelope shapes the sound.
  
  
• 9). Adjust the knobs until you get the sound the way you want it.
  
  
• 10
  
  To create an envelope that makes a sound achieve volume slowly, sustain as long as the key was held, and fade away really slow you would set your ADSR with values in these ranges: Attack, 96 to 127; Decay, 64 to 127, Sustain, 127; Release, 96 to 127.