Ok, know this might sound like a stupid question, but it's got me stumped.
Even after reading through the manual, scouring for an answer, I still am dumbstruck as to the difference between the EGR amount control on the front panel, and the Filter Poles setting in the Advanced Preset menu.
Is there a difference? And if so, what does the filter pole setting do?
EGR amount and Filter Poles: difference?
EGR amount and Filter Poles: difference?
Moog Matriarch, ARP Odyssey MKII, Roland Juno-60, Yamaha DX7, Yamaha VSS-30
Well the amount control tells the voltage to sweep either counter clockwise towards/away from 12:00 on the filter cutoff frequency, or clockwise towards/away the from 12:00 on the cutoff.
With the amount knob less than 12:00, a resonant filter will sound like OW, or can mimic a bass string being plucked (closing the filter to the envelope amount), and with the amount knob greater than 12:00 a resonant filter will make the WA sound, opening the filter.
[I used a resonant filter as an example, but the action of the filter is independant of the resonant setting of corse, I figured it would be easier to give an example of the sound this way]
Now the filter pole setting is in regards to the transister ladder type design. While I can't give you a technical description of what exactly is happening, I can tell you that if you restrict the number of poles the sound goes through, the filter will sound much brighter. It is a very nice sound to send noise through a 1 pole filter. Do this and you will get brighter and more mid range frequencies. The lows will kick back in when you bring it back up to 4 poles.
I think that this feature of the Voyager is by far one of my favorites to use.
I hope this answers your question.
With the amount knob less than 12:00, a resonant filter will sound like OW, or can mimic a bass string being plucked (closing the filter to the envelope amount), and with the amount knob greater than 12:00 a resonant filter will make the WA sound, opening the filter.
[I used a resonant filter as an example, but the action of the filter is independant of the resonant setting of corse, I figured it would be easier to give an example of the sound this way]
Now the filter pole setting is in regards to the transister ladder type design. While I can't give you a technical description of what exactly is happening, I can tell you that if you restrict the number of poles the sound goes through, the filter will sound much brighter. It is a very nice sound to send noise through a 1 pole filter. Do this and you will get brighter and more mid range frequencies. The lows will kick back in when you bring it back up to 4 poles.
I think that this feature of the Voyager is by far one of my favorites to use.
I hope this answers your question.
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tyrannosaurus mark
- Posts: 75
- Joined: Thu Dec 31, 2009 5:37 am
As I understand it:
The ERG amount is a mulitplier (-1 to 1) of the settings in the ASDR filter envelope. The envelope modifies the filter cutoff frequency set by the cutoff knob. This frequency is also where a resonnant peak is added by the ressonance knob.
The filter pole determines how the sharply frequencies above (since it is a lowpass filter) the cutoff frequency are eliminated. 1 pole= 6dB/octave, 2 pole =12 dB/octave, 3 pole= 18 dB, 4 pole=24 dB/octave.
During any stage of the envelope the frequencies above the cutoff are reduced or effectively eliminated depending how high above the cutoff frequecy a particular frequecy is and how steep the slope of the filter is.
A sine wave is the only waveform containing only one harmonic (the frequency of the note played). If the cutoff frequecy is set 2 octaves below a note played it will sound 12dB quiter on a one pole filter than any other note played that is below the cutoff frequecy. On a 4 pole it would be 48 dB softer or nearly non-existant. All the other waveforms are comprised of the sum of sine waves of different frequecies. In theory you need an inifinte sum, but if you look at a waveform a synth produces it is not perfect (squarewaves do not have vertical sides or perfectly flat tops). For example a squarewave is a sum of odd harmonics, it contains a sum of the fundamental frequecy and every odd multiple of the fundamental (though the amplitude of the each harmonic decreases). When a filter is applied to a non-sine waveform the slope of the filter changes the shape of the waveform for frequecies above the cutoff, since higher harmonics are reduced differently.
The ERG amount determines how high above or below the set cutoff frequecy the actual cutoff frequecy is during different stages of the envelope. The sustain section is the only envelope adjustment that affects the amount the cutoff frequecy is modified. The others set how quickly the change to the cutoff frequecy happens. The length of the sustain is determined by holding down the key.
Example of what the envelopes and ERG amount does:
The filter cutoff is set to 280Hz, the ERG amount is set to say +1/2, when the filter envlope fires the cutoff frequency starts at 280HZ increases to 400Hz during the attack, drops down to 300Hz during the decay, hold at 300Hz during the sustain, drops to 280Hz during the release. The pole number determines how frequecies above the cutoff is affected.
If the ERG amount is instead set to -1/2, the cutoff freuecy will start at 280Hz then during the attack it is dropped to say 160Hz raises during the decay to 260Hz then holds there during the sustain and returns to 280Hz during the release.
The ERG amount is a mulitplier (-1 to 1) of the settings in the ASDR filter envelope. The envelope modifies the filter cutoff frequency set by the cutoff knob. This frequency is also where a resonnant peak is added by the ressonance knob.
The filter pole determines how the sharply frequencies above (since it is a lowpass filter) the cutoff frequency are eliminated. 1 pole= 6dB/octave, 2 pole =12 dB/octave, 3 pole= 18 dB, 4 pole=24 dB/octave.
During any stage of the envelope the frequencies above the cutoff are reduced or effectively eliminated depending how high above the cutoff frequecy a particular frequecy is and how steep the slope of the filter is.
A sine wave is the only waveform containing only one harmonic (the frequency of the note played). If the cutoff frequecy is set 2 octaves below a note played it will sound 12dB quiter on a one pole filter than any other note played that is below the cutoff frequecy. On a 4 pole it would be 48 dB softer or nearly non-existant. All the other waveforms are comprised of the sum of sine waves of different frequecies. In theory you need an inifinte sum, but if you look at a waveform a synth produces it is not perfect (squarewaves do not have vertical sides or perfectly flat tops). For example a squarewave is a sum of odd harmonics, it contains a sum of the fundamental frequecy and every odd multiple of the fundamental (though the amplitude of the each harmonic decreases). When a filter is applied to a non-sine waveform the slope of the filter changes the shape of the waveform for frequecies above the cutoff, since higher harmonics are reduced differently.
The ERG amount determines how high above or below the set cutoff frequecy the actual cutoff frequecy is during different stages of the envelope. The sustain section is the only envelope adjustment that affects the amount the cutoff frequecy is modified. The others set how quickly the change to the cutoff frequecy happens. The length of the sustain is determined by holding down the key.
Example of what the envelopes and ERG amount does:
The filter cutoff is set to 280Hz, the ERG amount is set to say +1/2, when the filter envlope fires the cutoff frequency starts at 280HZ increases to 400Hz during the attack, drops down to 300Hz during the decay, hold at 300Hz during the sustain, drops to 280Hz during the release. The pole number determines how frequecies above the cutoff is affected.
If the ERG amount is instead set to -1/2, the cutoff freuecy will start at 280Hz then during the attack it is dropped to say 160Hz raises during the decay to 260Hz then holds there during the sustain and returns to 280Hz during the release.
