Hello all,
I am looking for some wonderful and generous smart people to help me out with a project. I know very little about electronics, and pretty much need someone to just tell me what to buy and what to do to make this work. Thanks in advance for anyone who decides to jump to the rescue!
I am a live sound engineer, and I use a special "pickup" on the low strings of pianos, and it sounds really great - except for one problem: whenever the sustain pedal is released (especially quickly) there is a thumping sound because all 88 dampers come slamming down on the strings all at once to mute them. I need to eliminate this thump. What I imagine doing is buying an Arduino board, hooking up some additional parts to it, stuffing it in a project box, and programing it to do the following:
If possible, run on the optional 48V "Phantom Power" supplied by the preamplifier in a Yamaha Rio I/O device. Otherwise, run on battery power. Then, I'll use either two phototransistor/LED pairs, or two Hall-Effect sensors (or Reed switches?) and magnets, positioning them one above the other on or near the piano sustain pedal pipe which moves up and down as the pedal is played. The idea here is that I need to create a 10kHz burst of noise whenever the pedal is released above a certain velocity. This burst will be fed into a channel on my audio mixer and used to trigger a short compression of the piano audio signal. So, since I'll be making all of my adjustments to things on the fly during a soundcheck, I'll need to quickly control a few parameters. I'll need a pot to set the timeframe from 0-100ms within which the bottom sensor on the pedal pipe is triggered after the top sensor has been triggered; if the triggering of that bottom sensor does not happen within this arbitrary amount of time after the top one has been triggered, nothing happens. Next, I'll need a pot to quickly set an overall delay for the 10kHz burst, from 0-100ms, because I want to perfectly time-align the burst and the thumping sound. The 10kHz burst can only last for 5ms, and needs to be a sine wave or close to it (no harmonics above 20kHz). I'll also need a pot to set the output level of the burst from 0-1.23V RMS (1.23V RMS is the maximum that audio mixer inputs will allow, and above which could damage things), and it will need to be output as a balanced signal ready for connection via XLR cable.
I plan to put the whole thing in a nice little project box with some clamps for fastening to the underside of the piano, and I'll have to work out exactly what mechanisms I'll use to trigger (or block?) the sensors at just the right times and places. I'd appreciate any suggestions on what kinds of sensors and mechanisms might work best here...
So who wants to help me out?? I'll need a lot of spoonfeeding, and some particulars here might change as I learn from y'all about what is even possible to do beyond what I'm thinking now. Thanks!