Author Archives: Michael Koppelman

Noises from the Arduino

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The Arduino is a little programmable doo-hickie that can be used for lots of things. I was playing with mine recently and hooked the digital outs up to an analog sound board. This is a common thing to do with the Arduino. You can coax the thing into making analog-like sounds through the digital output. Since it is digital, everything is a square wave.

All of these sounds were made with a little routine I got from the sample code for making a sound:

void playTone(int tone, int duration) {
  for (long i = 0; i < duration * 1000L; i += tone * 2) {
    digitalWrite(speakerPin, HIGH);
    delayMicroseconds(tone);
    digitalWrite(speakerPin, LOW);
    delayMicroseconds(tone);
  }
}

Here are a few little audio samples that I made tonight whilst fooling around. The first one is just random frequencies:

long i = 0;
  
i= random(5, 100);
playTone( i*i, 100 );

 

Arduino Random

The rest are just a sweep using different durations:

 
for(int i = 5; i < 100; ++i ) {
    playTone( i*i, 50 );
  }
for(int i = 100; i >= 5; --i ) {
    playTone( i*i, 50 );
}

Arduino Sweep Slow

Arduino Sweep Medium

Arduino Sweep Fast

Arduino Sweep Very Fast

It has digital and analog inputs as well, so my next goal is to use some sort of control voltage to make noises. More to come!

M.

Kick Drum Hacking

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Kick DrumOf course, in the ideal world, we get to spend a lot of time when mic-ing up the drums and try various tunings, microphones, rooms and signal chain so that the kick drum goes to “tape” with as little processing as possible and sounds great.

Then there is the real world. In the real world, the tuning of the drum is so-so, you have one or maybe two mics to choose from, time is running out and it’s time to hit the record button. So you’ll “fix it in the mix”.

In general, the kick drums needs a shit ton of lower mids pulled out — I usually center around 400Hz and I pull out as little as 5db or as much as 20db or even more! Then you need to put some low end back in, generally around 150Hz. But that pulls the sub-lows up too much so you have to roll off stuff below 50 Hz or so. Then, to add a little click and a little air, you want to jack up 2kHz and perhaps boost up a shelf at like 5kHz and above to bring in a little air.

You also have to make sure you’re not getting a lot of that 400Hz coming through the other mics. It tends to make the kick sound boxy. I usually attenuate 400Hz on the toms and the snare, too, for that reason.

I personally like to put the kick “above” the bass. So the kick will take the frequency space at 150Hz or so and the bass will center more down by 100Hz or so. Letting the kick take over the very low lows can be great for dance stuff. But, in general, the kick should hit you in the chest and the bass should rattle your ass.