The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "Simon Byrnand"
Subject: Re: Cancel speaker resistance?
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
Organization: Orcon Internet Ltd
X-Cache: nntpcache 2.3.3 (see http://www.nntpcache.org/)
X-Original-Trace: 16 Sep 2002 23:02:32 +1200, news.orcon.net.nz
Date: Mon, 16 Sep 2002 23:04:08 +1200
NNTP-Posting-Date: Mon, 16 Sep 2002 23:02:33 NZST
"Ban" wrote in message
> "Kevin McMurtrie" schrieb im Newsbeitrag
> > Is there any advantage in using current to voltage positive feedback to
> > cancel the coil resistance of a single speaker driver? Would
> > eliminating the 5-something Ohms improve the sound or is it
> > insignificant compared to other factors?
> I have tried something like this. A normal bass-speaker has a resonance in
> closed box, where there is a lot less current needed to get the same SPL
> then for higher frequencies. If you place a series resistor between
> and gnd you can feedback the current.
> It makes more sense to actually negatively feedback to get a very high
> output impedance, but the resonance has to be compensated. Now the driving
> current is independent of the speaker impedance, which varies a lot with
> temperature. The compression due to temperature variations is eliminated.
And the frequency response of the speaker is entirely changed, since most
(all?) drivers are designed to give their desired frequency response with a
constant voltage source, not a constant current source. Not only would you
get a big peak at the fundamental resonance, (which you suggest
compensating) but a climbing output at higher frequencies.
> This all makes sense only for very high-end sound systems with active
> crossovers and built-in amplifiers.
And I doubt they drive the actual speaker with a constant current
amplifier....(instead of constant voltage)
> ciao Ban
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup