Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site edison.UUCP Path: utzoo!watmath!clyde!burl!ulysses!gamma!epsilon!zeta!sabre!petrus!bellcore!decvax!ittatc!dcdwest!sdcsvax!sdcc3!sdcc6!ncr-sd!ncrcae!ncsu!uvacs!edison!dca From: dca@edison.UUCP (David C. Albrecht) Newsgroups: net.audio Subject: Re: on crossovers - active vs. passive Message-ID: <574@edison.UUCP> Date: Mon, 21-Oct-85 12:02:42 EDT Article-I.D.: edison.574 Posted: Mon Oct 21 12:02:42 1985 Date-Received: Sat, 26-Oct-85 04:46:17 EDT References: <1259@tekgvs.UUCP> Organization: General Electric Company, Charlottesville, VA Lines: 20 > Put a long-duration pulse to the speaker (long duration being > several times longer than 1 over the resonant frequency). The cone > moves out, then moves back. But when it moved out, it probably > over-shot the "correct" location and oscillated into place, finally > getting to where it was supposed to be. Thes oscillations generate a > "back emf" (remember that from your power engineering classes?) that > tries to drive the amplifier. I'm kind of interested in this also. I did see a circuit in a TI application guide which used a 5534 as driver for a low powered amplifier < 20 watts directly connected to a speaker. The unusual thing about it was the circuit used current feedback from the speaker by puting a 0.5 ohm resistor in series and feeding back the voltage to the 5534. I was curious if anyone had comments on the use of such feedback in multi-amp speaker designs (i.e. general usefulness, should it be used only for the bass drive or is it good across the spectrum, etc.). David Albrecht