CDP Sound Examples – FILTERS

Filter with time-varying frequency bands and Q

SOURCE SOUND

marimba6.mp3 (6 marimba strokes)

TRANSFORMATION

exflt1.mp3

DESCRIPTION
~ CDP Function: FILTER VARIBANK ~

• This example illustrates time-varying frequency bands and time-varying Q working together to produce a subtle interplay between harmonic character and pitch clarity.
• The breakpoint file exflt1vf.brk moves frequency bands inward from a 5-note C-7^th chord (C-E-G-Bb-C') to a unison on F# at 3 sec. and then outward again to a more complex 5-note harmony (C-D-E-B-C').
• Note that fractional MIDI values (i.e., microtones) may be used.
• At the same time, in exflt1vq.brk the Q factor starts with a fairly high (tight) level (400) in order to isolate the specified frequency bands. It then holds this Q level for 1.5 sec., after which it moves gradually to Q = 45 at 3 sec, a lower Q which lets through more of the original sound, and then moves back to 600 at 4.5 sec. to isolate the frequency bands of the new chord.

Additional Information

PARAMETER SETTINGS
(Click on image to view fullsize)

KEY POINTS

• Mode for using MIDI Pitch Values selected
• Double-filtering selected (more effective)
• Gain = 20 (to counterbalance the filtering)
• Harmonics = 5 (to add more timbral interest)
• Rolloff = -2 (modest amplitude decrease between harmonics)

SUPPLEMENTARY FILES USED

TIME-VARYING FILTER BANK (MPV = MIDI Pitch Value)

[exflt1vf.brk]
Time  MPV Amp   MPV Amp   MPV Amp   MPV Amp   MPV Amp
0.00  60 -3dB   64 -3dB   67 -3dB   70 -3dB   72 -3dB
3.00  66 -1.5dB 66 -1.5dB 66 -1.5dB 66 -1.5dB 66 -1.5dB
6.25  60  0dB   62  0dB   65  0dB   71  0dB   72  0dB

TIME-VARYING Q & other parameters

[exflt1vq.brk]
Time     Q
0.00	400
1.50	400
3.00	 45
4.50	600
6.25	600