Tuesday, October 29, 2013
Loudspeaker operation: The superiority of current drive over voltage drive
www.edn.com: This is an overview of the destructive effects that voltage drive has on the performance of electrodynamic loudspeakers. A more comprehensive treatment of the subject can be found in the book Current-Driving of Loudspeakers: Eliminating Major Distortion and Interference Effects by the Physically Correct Operation Method by Esa Meriläinen.
Today, practically all available audio amplifier and loudspeaker equipment works on the voltage drive principle without significant exceptions. This means that the power amplifier acts as a voltage source exhibiting low output impedance and thus strives to force the voltage across the load terminals to follow the applied signal without any regard to what the current through the load will be.
Subscribe to:
Post Comments (Atom)
1 comment:
This article was a great help on deepening my understanding of impedance, voltage, and wiring for loudspeakers and amplifiers.
I’ve never heard of the “voltage drive principle” that the author talks about in the article. Seems like it just refers to the fact that a power amp provides voltage to the speaker, and the power amp has lower impedance than the speaker. This aligns with my previous understanding of impedance across a signal chain- the speaker must have greater impedance than an amp, because if an amp has greater impedance, it might not have the power capabilities (enough watts) for the speaker. I didn't fully understand the line: “[the power amplifier] strives to force the voltage across the load terminals to follow the applied signal without any regard to what the current through the load will be.” I understand the power equation P = V x C, but don’t understand how voltage is converted to current. I understand that with a constant voltage source, the current varies with the load’s impedance, according to Ohm’s Law.
I’ll keep learning about this topic to fully understand.
Post a Comment