ACO160EVK
Audio‐to‐Synth Evaluation System
4
999 SW 1
st
Ave. #1617, Miami, FL 33130
Quick Start Guide to your ACO160EVK system
Thank you for choosing to evaluate this ACO160EVK system! Here are some basic instructions to make
the most out of your ACO160EVK board:
Basic Setup
1) Apply power via the included 9v power supply unit (PSU). This unit can handle 100‐240VAC at its
input so will work worldwide, possibly with only a adapter for your local electric socket required.
2) Connect any audio input via the Neutrik combo jack (XLR or ¼” balanced or unbalanced).
3) Play your audio source at a comfortable volume and adjust the preamp gain until the highest green
LED lights up on the peaks. If the gain is too high, the preamp will clip and the fundamental frequency
detection might not work. Note that the red overload LED does not light up no matter how large the
signal at the preamp out!
4) Adjust the gate threshold so that the gate LED turns on when no audio is being played. With plucked
string instruments like guitar it may take some tuning to get the gate to differentiate exactly when a
note is being played from the low‐level transients that occur when you mute the strings. Try to set the
gate high enough so that the LED remains on when those quiet transient events occur.
5) For almost all cases the HPF and LPF can be left in their default, “open” settings (HPF OFF and LPF at
5kHz). In some extreme cases changing these filtering settings can help, for example if you use a contact
mic with a handheld instrument and want to filter out potential low‐frequency knocks or percussive
effects.
Listening to ACO Analog Outputs
6) Listen to the ACO output via the ¼” main output. To hear the dry + wet sound, connect a 1/8” patch
cable between the “LINE OUT” and the “AUX IN” minijacks and adjust the AUX MIX knob to get the
desired mix (fully CCW for dry, fully CW for wet). Adjust the master volume (“OUT LVL”) knob to get the
desired level coming out of the EVK.
7) Select SIN/SAW/SQR waves via the 3‐way switch to hear the different ACO waveforms.
8) Adjust the ENV RATE SELECT rotary switch to optimize the frequency tracking for the audio source
chosen. NOTE: This should be an 8‐position switch, but in this version of the EVK the assembly house
installed a 4‐position switch by mistake. I modified the PCB so that every other rate setting is accessible
from the fastest to the second slowest. Instruments with very fast attack/decay and low power in the
harmonics (like guitar and bass guitar) should work well with fast envelope rate settings (CCW) whereas
instruments with slower attack/decay and strong harmonics (like bowed strings) should work well with
slow envelope rate settings (CW). Human voice should work well somewhere in the middle.
9) Adjust the “HARM” knob to hear the various pitch shift settings. Here it is especially useful to mix the
dry and wet signals together so it’s easier to hear what harmony interval is tuned. Note that the
harmony knob is continuous, it does not give you “clicks” when moving from one harmony to another.
