Korg MICRO manual Filter Vocoder, Formant Shift, Sense

6.FILTER — VOCODER

By using "FORMANT SHIFT" (knob 1) and "CUTOFF" (knob 2) to shift the cutoff frequency of each band pass filter of the carrier (the "synthesis filter"), you can raise or lower the frequency response while maintaining the character of the modulator, thus varying the character of the vocoder output. Both of these knobs do the same thing, and have the same range. FORMANT SHIFT is indexed to shift from filter to filter, and CUTOFF is continously variable. In addition, you can use "E.F. SENSE" (knob 4) to adjust the sensitivity of the Envelope Follower for the modulator, in order to vary the smoothness of the attack and the length of the release for the vocoder output.

FORMANT SHIFT

[0, 1, 2, -1, -2]

Shifts the cutoff frequency of each band-pass filter of the carrier, in units of filters.

CUTOFF[-63...63]

This continuously shifts the cutoff frequency of each band-pass filter of the carrier.

RESONANCE[0...127]

Specifies the amount of resonance for each band-pass filter of the car- rier.

Increasing this value will empha- size the regions near each cutoff fre- quency.

E.F.SENSE [0...126, Hold]

Specifies the sensitivity of the En- velope Follower for the modulator. Lower settings of this value will al- low the attacks of the input signal to be detected more rapidly.

If you set this to Hold (), the character of the signal that is being

Table 6-1

Frequency			Band (CH)
[Hz]	Formant shift 0		Formant shift +2		Formant shift -2
39
50
65					1	(CH1)
80					2
125	1	(CH1)			3	(CH2)
185	2				4
270	3	(CH2)	1	(CH1)	5	(CH3)
350	4		2		6
430	5		3		7

"FORMANT SHIFT" and "CUTOFF"

Each parameter allows you to vary the character over a range of two steps upward or downward (a total of four steps upward or downward when used together). If both of these parameters are at 0, the character will match the cutoff frequencies of the modulator band pass filters (the analysis filter).

BPF	BPF	BPF
7	8	9

Frequency

-63 0 +63

Cutoff (range in which BPF 8 will change)

Formant Shift:+2

	BPF	BPF	BPF
7		8	9		Frequency
-63		0		+63
		Cutoff (range in which BPF 8 will change)

input at that moment will be held. Subsequently, the sound will retain that character regardless of whether there is any input.

The signal information that is maintained in the Hold state can be saved in the program by writ- ing the program.

If you set this to Hold when there is no input signal present, there will be no output even if an audio signal is subsequently input.

This value will automatically be set to Hold if you press the FORMANT HOLD key. Hihger values will retain more of the sound’s natural decay.

		(CH3)		(CH2)		(CH4)
530	6		4		8
630	7	(CH4)	5	(CH3)	9	(CH5)
780	8		6		10
950	9	(CH5)	7	(CH4)	11	(CH6)
1150	10		8		12
1380	11	(CH6)	9	(CH5)	13	(CH7)
1680	12		10		14
2070	13	(CH7)	11	(CH6)	15	(CH8)
2780	14		12		16
3800	15	(CH8)	13	(CH7)
5000	16		14
6400			15	(CH8)
8100			16
10510
12600

Although the microKORG's editable band-pass filter has eight channels, it internally contains sixteen band- pass filters. These sixteen filters are arranged in pairs (a pair for each channel). Table 6-1 shows how the frequencies adjusted by "FORMANT SHIFT" and "CUTOFF" correspond to the frequencies of the sixteen filters.

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