|
Hegglun Ian
 Ian Hegglun was born in New Zealand and has enjoyed designing audio power amps as a hobby since buying a Sinclair Z30 module and modifying it. After an interlude at a university to gain an electrical engineering degree he resumed designing amplifier and speaker systems including motional feedback, negative resistance damping and current drive. A fascination with linear mode CMOS inverters lead to the discovery of their square-law basis and then use in unusual power amp designs. CMOS inverters were used in an Electronics World Class-AB amplifier in 1995. More recent designs use curved type Class-A.
Ian also has an interest in homopolar motors for electric cars and gained his Masters in this area. He has worked as a registered power engineer and taught electronics in New Zealand, and worked in manufacturing in Australia. Ian took 6 years off work recently to set up a private electronic library and to be with his Dad during his last few years. He hopes to set up a website to share his many ideas. He is now living in Austalia. |
|
|
Towards a reconciliation of measurements with listening tests
Ian Hegglun
 Standard THD measurements give a clear indication of amplifier linearity for the signals with which it is measured. Curiously, however, very often THD performance does not seem to correlate with listener preferences. There have been attempts to develop measurement protocols that correlate better with subjective performance, but not with complete success. Ian Hegglun picks up the gauntlet, and argues that much of the problems stems from the fact that human hearing has a sensitivity for harmonics of the signal that varies enormously with the order of the harmonic, making a measurement that lumps all harmonics into a single number a recipe for failure. Ian quotes research that shows that audibility of higher harmonics is many 10’s of dB higher than that for lower harmonics. His novel weighting filter boosts relative levels of higher harmonics based on these findings with a resulting performance number that much better correlates with listener preferences.
Volume 4 |
|
|
|
|
<< Start < Prev 1 2 Next > End >>
|
|
Page 1 of 2 |
Hegglun Ian
