Some of the recent questions I heard from the students were about filters. The world of filters, whether active or passive, is a complex one. There’s a lot of documentation about this subject and if you have to design a particular filter for a particular frequency, you will encounter quiet complex math. I added some examples of second order LP, HP and Bandpass filters and included some on-line calculators.
Since it is almost holiday and most of the students already left to enjoy the summer, I have some more time to add content to the website.
I started with some more theory about passive filters, voltage dividers and some better graphics to explain the opamp circuits that I use quiet often. Also some complete oscillator circuits and amplifiers. Hope you can use the examples in your own work. Something like this for example:
I will explain about the amplification of small signals with opamps.
and I added some nice oscillator circuits and more theory
It is still not finished (when will it ever be;-)) but it’s a start.
Have a nice summer!
This last month I finished the experiments with the 16bit DA converter, based upon the PT8211 low cost DAC-chip. The new board receives OSC (OpenSoundControl) and converts it to 6 times control voltages (CV) from -5V / +5V, with a resolution of 16bit (0-65535).
To be able to implement the vdPol Oscillators/Filter in the RC studio’s I created this card to be able to have full (digital) control over the frequency and ‘Mu’ of the vdPol. Two of the CV outputs of the DAC are linked to 2 VCA’s.
I will design a printed circuit board for this circuit soon, so more students can make use of the 16 bit OSC-CV conversion.
The version of the vdPol Oscillator/filter shown below, is a special version that has a ‘Vactrol’ on board that replaces the ‘mix’ potentiometer. By connecting the internal led of the Vactrol (through a resistor) to one of the DA board CV outputs, the resistance can be varied between 100Ohm and 1MOhm. So now the mode “Oscillation” (low resistance) and “Filter” (high resistance) is determined through one of the outputs of the DA-board. In a more conventional setup this could also be realised with an external CV input of course – making the vdPol even more interesting to embed in your modular! 😉
In the past few months we developed a “vdPol oscillator and filter”. This device, named after its founder, is an interesting circuit which consist of multiple integrators (inverting opamp-circuit with an capacitor as feedback component) in a loop with signal multipliers (4-quadrant multiplier = AD633) .
I made multiple versions of the vdPol oscillator that can be used in combination with analogue studio Bea-5 (banana connectors) and the Doepfer set (mini jack connector).
At this point we still think the design of the vdPol can be improved. The tweaking and search of stability versus interesting sounds and behaviour is still in progress. To make the experimenting and tweaking more interesting, I designed a printed circuit board. Now more vdPol oscillators and filters can be connected together in one chain (or feedback-loop), creating very rich audio-patterns.
Friday 9th of February, I introduced students to the world of the Remote Controlled studio during a 2 hour session at Sonology studio Bea-6. It was an introduction lesson in how to use the RC-studio and how communication can be setup with OpenSoundControl messages (OSC).
Since the big Max/Msp patch that I made for driving the whole setup is quiet a mess (:) when you go out of presentation-mode, I added the core-processes as separate Max/msp patches. In this way it is easier building a patch yourself by adding the core-parts together. You will find patches that can work stand-alone and that generate the right OSC-messages like /v1, /cf, ma, /st and more. Take a look at the download section and find 7 new Max/Msp patches to be experimented with. For more information about the RC-studio, check this.
Example of the ADSR module drive:
After 4 years of hosting the Ipson webiste with Joomla 3.x, the amount of work for updating the website to a newer version of Joomla would have been too much (in my opinion).
I decided to host the website with another CMS: WordPress – it seems more elegant to work with so I will give it a try. The Ipson website structure will be the same as the old one, but in the background a lot of documents and images have been removed and it is more ‘clean’ at this moment.
Since I finished my master research in June 2017, I also have more new material the share on this website.The CompLex (OSC-driven audio-matrix), a new 16bit DA converters (still in the make) and much more interesting student projects. Also the development of the RC (Remote Controlled) analogue studio continued and will be shared on this website.
I hope you like the new setup.