IUBio Biosequences .. Software .. Molbio soft .. Network News .. FTP


John Fields starship at freeside.fc.net
Thu Jun 5 08:55:09 EST 1997

Arny Krüger (arnyk at pop3.concentric.net) wrote:

: Luc.vanHoye at ping.be wrote in article <33935466.1CC at ping.be>...
: > I am trying to figger out if the impedance of an audio device has
: > something to do with how loud its signal can go...

: It does not.

: Impedance and sensitivity are separate specifications.
It does.

Consider an amplifier with an 8 ohm output impedance feeding 8 volts into 
a speaker with an 8 ohm impedance.  The speaker will be dissipating 8 
watts of power and will generate a specific sound pressure level.

Next, consider the same amplifier putting 8 volts into a 16 ohm load.
Since P = E^2 / R, the power being pumped into the load is 8^2 / 16, or 4 
watts, which will yield a lower sound pressure level.

The assumption, of course, is that both speakers have the same efficiency 
and are, in fact, identical except for their impedances.

John Fields

More information about the Audiolog mailing list

Send comments to us at biosci-help [At] net.bio.net