Motional feedback in speakers
On Thursday, November 7, 2019 at 4:32:20 PM UTC-5, Trevor Wilson wrote:
> > Regarding feedback, I remember there was an hobby project long ago to
> > have a very small R between speaker and GND (GND also being the amp's
> > ground), and using the speaker's back EMF as feedback to correct
> > excursions. There are some later publications from W.Kippel about it.
> **The first system I saw with that arrangement was the Infinity RS1. It
> introduced as many problems as it solved. Amplifiers with 'floating'
> output stages encountered some problems. Bridged amplifiers too. That
> said, the bass extension available from a rather modestly sized, sealed
> enclosure was impressive.
May well be the case, but it wasn't because of feedback. If there
was anything done electronically, it was EQ which, itself, is a
completely legitimate way of getting bandwidth, if done properly*.
* Which, of course, is subject to Dick Pierce's First Law
of Acoustics: Anny idiot can design a loudspeaker and,
unfortunately, many do.