Archive for October, 2009

Seno DS *ADSR volume envelope* (NDS, 2009)

October 25, 2009

“An ADSR (attack-decay-sustain-release) envelope is a component of many synthesizers, samplers, and other electronic musical instruments. Its function is to modulate some aspect of the instrument’s sound — often its loudness — over time.” (Wiki)

This is how the ADSR envelope is done.

The four characters stand for Attack time, Decay time, Sustain level and Release time.The above figure should give you a glue what this is all about. The envelope gets triggered as soon a key is pressed. After that, it raises to the maximum level (AR), and falls down in the decay time (DR) until it reaches the sustain level (SL). This level falls down with the sustain rate (SR).

After releasing the key (this is by default every new step in Seno DS), the envelope falls down to zero with a release rate (RR).

Here you see how you can edit the curve in Seno DS.



Fixed Point Math (NDS)

October 23, 2009

I use this fix point C++ class while  developing for the NDS. The class uses NDS native fixed point format – which is used i.e. for the 3d matrix.

There are occasions where I need floats (not for Seno DS I guess)