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9730 Dual VCF w/Modulator Test Page

This page is supplemental material to the 9730 Assembly and Using manual.
Note: The test sound file may take a few second to download. File will open in a new window.

test 4Test 4 - These tests verify the operation of the two filter sections independently. The four tones in the sample are 1) Square Wave Input 2) Hi Pass 3) Band Pass and 4) Lo-Pass. All tones were recorded at the same input level and the difference in volume is the normal result of the harmonic structure of the square wave. For example, Lo Pass is very soft because most of the harmonics of the input sqare wave are higher than the Corner Frequency and are consequently attenuated. The Hi Pass ouput is relatively strong because the higher harmonics are passed without attenuation. Fc in this example is about 128 Hz. - the four octave total range of the Freq control above the 16 Hz. "0V CV" frequency.

Test 5 - Checks the operation of the modulator, first with Q set as shown above and then with Q control manually advanced from min to max while sweeping Fc with the modulator.


test 6Test 6 - Verifies that the normal patch of filter A LP output to filter B Input is intact. With Fc of the two filters offset from one another both resonant peaks can be heard.

test 7Test 7 - Verifies normalized patch from Fc2A to Fc2B. Early version of the manual stated that this increases the range of the modulator from 5 octaves to 10 octaves, but in fact with Output Control maxed, as in this sample, the filter is sweeping 15 octaves.