Colundi on the µTune

Colundi µTune logo

Introduction to Colundi

Some users of our µTune eurorack quantizer and midi interface have asked if about the Colundi scale and how to use it with µTune.

Here is a quick tutorial how to set it up.

The Colundi Scale is somewhat different from traditional scales in that it consists of absolute pitches, rather than relative intervals.

There are different Colundi scales, in this tutorial we will use the list published here:
http://colundi.net/data.php

The scl. file we created using these frequencies can be found here:
Colundi scl file

Update: Here is the scl-file for the complete final list with 128 frequencies:
Colundi-full-everyOne.scl

At the end of this tutorial, we will show how to create such a scale file yourself.

Using a Colundi scale file with µTune

Using the Colundi scale file is pretty simple with µTune. This explanation might look complicated, but it is only very detailed.

  1. Put the scl file on the SD card an load it in µTune
    (Alternatively you could use µTune’s scale editor and enter the scale manually)
  2. We need to define a reference frequency used by µTune’s tuner:
    As a reference you could use the lowest note (10.8Hz), but probably more practical is to use a note in the audible range. Looking at the list of frequencies again, we notice that note number 30 is supposed to be 440Hz. Great.
    Go into TUN->Scale Mapping and define out reference note to be 29 (The base note is note 0) and the reference frequency to be 440Hz. (Note: You can use any other note and frequency as a reference)
  3. µTune is now able to calculate all absolute frequencies of your scale.
  4. Connect the output of your VCO to µTune’s GATE-in input. This can be used to measure the VCO’s frequency.
  5. In µTune’s tuner, you can use different display modes. You could display the frequency in Hz and check the frequencies of the different notes. Better is to use ‘relative mode’ to display the difference between the expected and measured frequency from the VCO.
  6. Adjust the Tune knob on your VCO until it is in tune. You might have to adjust The ‘Middle volt’ and ‘middle note’ settings to get the VCO in range. Please refer to the µTune user manual chapter ‘Scale Mapping’ for a detailed explanation.
  7. You can now play your Colundi scale and have fun!
  8. Optionally: You can now also use the ‘automatic tuning’ feature to make sure your VCO stays in tune automatically at all times

Creeating a Colundi scale file yourself

As you can see, the first frequency is 10.8Hz, followed by 33Hz, 33.8Hz, 55Hz,…

We now have to convert these frequencies into ratios based on the base frequency and calculate the difference in cents.
By the time of writing this, in Scala you can enter the frequencies directly, Scale workshop does currently not support this however. A simple Excel script can do the job for you as well.

Our base frequency fbase = 10.8Hz which we define to be 0 Cent.

The cent distance from our base frequency can be calculated as:

cent = 1200 × log2 (fn / fbase)

The cent value of out next frequency f1 = 33Hz can therefore be calculated as:

cent1 = 1200 x log2 (33Hz / 10.8Hz) = 1933.72165 Cent

The next entry in our scale is:

cent1 = 1200 x log2 (33.8Hz / 10.8Hz) = 1975.19032 Cent

ans so on.

When you are done you can use your list to create an .scl file. You can do so using Scala, Scale Workshop, µTune’s scale editor or a simple text editor. The .scl file format is very simple and described here.

COVID-19 info

  • Online shop is open
  • Shipping costs can not be guaranteed*
  • Shipping delays to be expected
  • Shipping once a week
  • No repairs, mod installs or service

Due to the COVID-19 epidemic, schools and kindergardens are currently closed in Berlin.
As a result Tubbutec staff will spend more time at home and less at work. Production of synth mods is slowed down, but not halted and we have considerable stock of most products. We therefore decided to keep the shop open, but only ship once a week until further notice.

* The situation on shipping changes daily. Deutsche Post – our international shipping partner – has already stopped delivering to some countries and more might follow. There are alternatives, but they are more expensive. Instead of 8€, you might need to pay 20€-33€ shipping. Because the situation changes so quickly we can not guarantee that an order with 8€ can actually be shipped. We will contact you if that is the case. The following countries are already affected: USA, Canada, Australia, Argentina, China, Japan, New Zealand, …

Mod installs, repairs and other service will halt until at least the mid of April.

Support will continue as time allows, but is likely to be slower than usual.

thank you very much for your understanding

-Tubbutec Team

Update: 24.3.2020
– We shipped all orders yesterday, next shipping probably even this week.

Update 31.3.2020
For the following countries, shipping via priority mail has stopped due to Covid-16. As an alternative, DHL or UPS express shipping methods are offered, the mean however higher cost.
– USA
– Australia
– Canada

Korg Minipops 3 midi with uniPulse

This manual shows how to install uniPulse in a Korg MiniPops 3 (aka Univox SR-55 and Aria Diamond) and trigger all 9 instruments via midi.
The installation is fairly simple and only requires soldering a few wires and parts into place, as well as drilling a hole for the midi socket.

Trigger connections

Here we see the 9 trigger points for the various instruments. These are trigger outputs P1-P9 from uniPulse directly soldered to the trigger points.

uniPulse power supply

In order to power the uniPulse you need to add a few parts, but it is rather simple. The following image shows how we added an additional diode resistor and capacitor in order to get a positive supply voltage for uniPulse. These parts are included in the kit on request. This is a 100uF capacitor, a 1N4148 diode and a 2k resistor. The resistor avoids high voltage spikes, its value is not critical. A 2.2k resistor can also be used.
As you can see the capacitor is connected to the black GND connection with its negative pin, the diode feeds a positive voltage to its positive pin. The resistor is soldered across the capacitor. The brown +V wire from uniPulse is connected to the positive side of the capacitor.

Ground connection (red GND wire from uniPulse) can be connected at the point seen below.

Installing the midi socket

Installing the midi socket is simple. A drill guide is included in the kit. Any location is fine, we chose to install the socket in the cable compartment of the machine. The white marking on the midi connector points inwards on the uniPulse board.

Config file upload

After installing uniPulse, turn on the machine and make sure the LED on the uniPulse is turned on. This means it has power and is running.
Connect midi and use the config tool to upload the following configuration.

Config file (right click, save as)

have fun!

 

Christmas Holiday

Merry Christmas and a happy new year!
We’ll be closed for 2 weeks until the 2nd.

Last day of shipping is this Thursday the 19th. We will of course accept orders after that, but these will be shipped on the 2nd next year.
Please understand that there will only be limited support during our absence, but we will of course be back for you next year.
Have a nice time and enjoy the Holidays !