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Filters & Effects
The instruments on this page are mostly templates to assist in Csound software synthesis composition. Some of the instruments are filters, while others were used to create specific compositions. A complete understanding of software synthesis can be found in The Csound Book, as well as in tutorials and on websites of advanced users listed at www.csounds.com.
Most of the instruments are configured to run with the ZAK system, which works similarly to a patchbay. Except for the mixers and the stereo reverb, the instruments have one input and one output. To make stereo instruments, a second input and a second output can be added to any filter or effect. (The configuration would resemble the in-out parameters used in the stereo reverb listed below.)
I decided it would be most useful to provide isolated, non-operative processor instruments for the most part, which can be added to any .orc or .sco file. The "example" and the "flute choir" are working scores, for those who are not familiar with using the ZAK system. "Transversal Meditation" is also a working score, but I could not include the samples I used, because they were too large. The "Cross-Synthesis Phase Vocoder" orchestra's samples were also too large to make available for download, but there is an .mp3 file of the final result found in the Phase Vocoder zip below.
Click the underlined links to download score & orchestra files
Example: Four part Bach hymn with the high and low frequencies boosted, in separate instruments, with individual reverb settings for the upper and lower parts. Each part is sent to a discrete mixer channel, where it is panned before being sent out.
|FILTERS||EFFECTS, MIXERS, & TEMPLATES|
|Low Pass Filters
3 filters, using the Butterworth lowpass opcode. 01 is an 8th order filter, 02 is a 4th order filter, and 03 is a second order filter. Higher order filters have a steeper cutoff curve.
Mono and stereo reverb effect using nreverb opcode. Adjustable reverb time, wet/dry amount, high frequency rolloff, and high frequency diffusion rate.
|High Pass Filters
3 filters, using the Butterworth highpass opcode. 01 is an 8th order filter, 02 is a 4th order filter, and 03 is a second order filter. Higher order filters have a steeper cutoff curve.
Flanged effect using vdelay3 opcode.
|Band Pass Filters
6 filters, using the Butterworth bandpass opcode. 01 covers a wide frequency range, and 02, 03, 04, 05, & 06 cover portions of the audible frequency range. Each filter has 9 variable frequencies accessed through a table.
Sound delayed 4 times for light chorusing, using vdelay3 opcode.
|Band Reject Filters
3 filters, using the Butterworth band reject opcode. 01 is an 8th order filter, 02 is a 4th order filter, and 03 is a second order filter. Higher order filters have a steeper cutoff curve.
3 mixers, with individual gain and pan for each channel. Mix2: 2 in 2 out; Mix4: 4 in 2 out; Mix8: 8 in 2 out.
5 band equalizer, built with Butterworth lowpass and highpass filters. Variable frequencies located in a function table.
3 score templates, using various filters. 01 has a bandpass filter, an 8th order lowpass filter, an 8th order highpass filter, a 5 band equalizer, a stereo reverb, and an 8 channel mixer. 02 has a 4th order lowpass filter, a 4th order highpass filter, a 5 band equalizer, a stereo reverb, and a 4 channel mixer. 03 has a 2nd order lowpass filter, a 2nd order highpass filter, a 5 band equalizer, reverb, and a 2 channel mixer.
Physical Models of Instruments
Piccolo, 2 Flutes, Alto Flute, Bass Flute, Contrabass Flute
The orchestra is comprised of six flute instruments, six EQ instruments, three stereo reverb instruments, and a six channel mixer. There are variable tables to control each choir member, as well as ten parameter fields, many variable arguments within each choir instrument, several EQ settings, several reverb settings, and six individual gain and pan controls. Because of the many tables in the score, the score will render faster using the console version of Csound.
When auditioning individual choir sounds, it is easy to mute other instrument(s) by commenting the beginning of the EQ instrument line(s). This prevents the instrument(s) from going into and out of the mixer. For example: to mute EQ instrument 95, make the individual EQ line in the score example look as follows: ;i95 0 16 .2 .3 .4 .3 .2 5 11 To unmute instrument 95, remove the semicolon and re-render the score, putting it back in the signal flow.
Each member of the choir is routed to a separate EQ instrument, and then into the inputs of the reverb instruments. The six outputs from the three reverb instruments are then sent into a six channel mixer, with individual gain and pan for each channel.
Piccolo, 3 Flutes, Alto Flute, Bass Flute, Contrabass Flute
Based on the sonority exercise of Marcel Moyse (Published in 1934, Leduc)
A descending chromatic scale, modulating every two measures, is distributed among the seven instruments. Thematic lines intertwine with and at times obscure the scale, with an accelerando at the half way point and at the end of the piece.
The Alto Flute is treated with a chorus effect, and the Bass Flute is processed with a flanger. Each instrument passes through an individual equalizer and a reverb unit. Piccolo and Flute 2 are panned left; Flutes 1 and Alto Flute are panned right. Bass Flute and Contrabass Flute are panned center. Each instrument is assigned to a separate mixer channel. The methods of editing every sound parameter are explained in the orchestra and the score file.
The orchestra is comprised of seven flute instruments, seven EQ instruments, one flanger instrument, one chorus instrument, three stereo reverb instruments, one mono reverb instrument, and a seven channel mixer. There are variable tables to control each choir member, as well as ten parameter fields, many variable arguments within each choir instrument, several EQ settings, several reverb settings, and seven individual gain and pan controls. Because of the many tables in the score, the score renders faster using the console version of Csound.
When auditioning individual choir sounds, it is easy to mute other instrument(s) by commenting the beginning of the EQ instrument line(s). This prevents the instrument(s) from going into and out of the mixer. For example: to mute EQ instrument 95, make the individual EQ line in the score example begin as follows: ;i95 To unmute instrument 95, remove the semicolon and re-render the score, putting it back in the signal flow.
Each member of the choir is routed to a separate EQ instrument, and then into the inputs of the reverb instruments. The seven outputs from the four reverb instruments are then sent into a seven channel mixer, with individual gain and pan for each channel.
Flute Choir signal flow
Cross-Synthesis Using Phase Vocoder Opcodes
Cross-Synthesis Orchestra Template, for up to 4 Discrete Sounds
PVBUREAD and PVCROSS are used with the ZAK system to cross-synthesize 2, 3 or 4 samples. The score has two vocoder instruments, two equalizer instruments, one stereo reverb instrument, and a two channel mixer. The pitch, tempo, and amplitude are variable within the vocoder instruments. The 5 band EQ tables can be set to any frequencies. The reverb instrument has several variable parameters, and the mixer can be used for stationary or moving pan effects.
I used this orchestra to combine
a phrase of a Mozart Symphony with the coda of The Beatles' Hey Jude,
since they share a chord progression. Only two sound samples were used,
but one of them was used twice, at different speeds. A thorough
explanation of the project is found in the following six page paper,
PhaseVocoder. Also included with the paper are the .sco
and .orc files I employed, and an .mp3 file of the final
result. The actual .wav samples are too large to include. The "cross-synthesis
zip at the top of this box has similar .sco and .orc
files, but without the
specific parameters. It is intended as a template for cross-synthesis of up to 4
discrete sound samples.
Using a similar orchestra to the one directly above, two excerpts from The Carnival of the Animals by Saint-Saens were cross-synthesized. Actually, this project was suggested by a ten year old student. I played two parts of Carnival of the Animals for a fourth grade class, "The Elephants" and "The Aviary". One student said, "what about a flying elephant, like Dumbo?" The file includes the score & orchestra files, and an mp3 of the final result. I used the Csound defaults for the "Birds" .pcv file, and a window factor of 8 for the "Elephants".
I took a short excerpt from each piece, and put them into my phase vocoder orchestra. First I ran the Birds & the Elephants through 8th order high pass and low pass filters, respectively, to eliminate the accompanying parts. (These filters are found above) When I was satisfied with the sounds, I transposed the parts, so that they were in the same key. Amplitude, panning, and time alterations were used to create some interesting effects, before applying reverb and panning.
Marching To The Sirens Of War, 2005
Flute instruments similar to those used in Transversal Meditation create an 18 measure canon, which battles its way through a choir of siren-like glissando instruments. A droning bass marches underneath.
Scored for 2 flutes, bass, and 3 glissando
instruments, this short piece features a great deal of control for each
part. The score is well-commented, explaining how the parameters of
sound were created. There are quite a few tables which must be loaded,
so rendering the composition with winsound takes a long time. Using
consound, it only takes about 30 seconds.
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