The KORG Sync Protocol

Well, I wouldn't call it protocol  smiley Have a look at this first picture. 

This is what I measured when I hooked up an oscilloscope to the SYNC OUT of my Electribe 2. There are several things to note:

  1. The amplitude is 5V
  2. This signal is available on the TIP-Connector of the 3,5mm TRS Connector. The SLEEVE and GROUND-Pins have permanent LOW.
  3. The signal does not stop when you hit the STOP-Button on the E2. It just continues. This implies, that there is no way to tell the SLAVE device when to stopp. If you hit STOP on the Master Device (in my case the E2) and hit START again, the impulses do a quick shift and align with the precise time you hit Start on the E2. That's all. Your Slave-Device will be in Sync, but you have to start it yourself at the right moment.

Now let's have a look at the time. At 130BPM I measured 230ms between the two pulses. I did some other measurements on various freqencies.

BPM Measured Time between Pulses Calculated Time between Pulses Calculated Time between Pulses /2
20 1500ms 3000ms 1500ms
60 500ms 1000ms 500ms
100 300ms 600ms 300ms
110 279ms 545ms 272ms
120 250ms 500ms 250ms
130 230ms 461ms 230ms
170 177ms 352ms 176ms
200 150ms 300ms 150ms
250 120ms 240ms 120ms
300 100ms 200ms 100ms

The BPM ranges from 20BPM to 300BPM on the E2. I set the BPM shown in the "BPM"-Field on the E2 and measured the interval between the pulses on the oscilloscope. The result is in the "Measured Time between Pulses"-Column.

So there must be a connection between the BPM and the time between pulses. I then created the "Calculated Time between Pulses"-Colum. This column shows, how much time passes between Beats if you assume a certain BPM: 60 seconds / 120 BPM = 0,5s = 500ms. Close enough.

In the Row "Calculated Time between Pulses /2" I divided this value again by 2 and the result was very near to the measured value.

tl;dr The Snyc Protocol puts out 5V Pulses with the double speed of the selected BPM. At 130BPM you get Sync Pulses at 260BPM.

There are two more options in the Electribe 2. The first is "Sync Lo" vs. "Sync Hi". This just changes the polarity of the impulses.

Then there ist the option "2 Steps" vs. "1 Step". With "2 Steps" being the default, "1 Step" doubles the resolution again by inserting another Pulse.

The Electribe 2

According to these pictures the following ICs are used in the E2: