Attack transients of free reed pipes in comparison to striking reed pipes and diapason pipes

Attack transients of three free reed organ stops were measured throughout t he whole frequency range of the stop and compared to the measurements of a striking reed stop and a flue stop. The purpose of the measurement was to e xamine why free reed pipes are often judged to have a sluggish attack. As t he results show, the attack transients of free reed pipes differ in a numbe r of parameters: rise time, amplitude and initial delays of the partial ton es from striking reed pipes and flue pipes. In addition free reed pipes and striking reed pipes do not start with a chiff which is typical for diapaso n pipes. The analysis showed that the rise time of free reed pipes is short er than that of striking reed pipes, but often in the same order as the ris e time of the diapason pipes. A psychoacoustical test was conducted and rev ealed that parameters other than rise time, namely different initial delays of the partials and the presence of the chiff, in the case of the diapason pipe, might lead to the perception that the attack duration of the free re ed pipe is longer than that of the diapason pipe.