Changing amplifier impedance loads

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=54079
Printed Date: July 12, 2025 at 7:58 PM

Topic: Changing amplifier impedance loads

Posted By: crimson reign
Subject: Changing amplifier impedance loads
Date Posted: April 17, 2005 at 10:38 AM

Is it possible to change the load on an amplifier by adding resistors? Lets say you have a single 4 ohm woofer wired to an amp that puts out 50 watts into a 4 ohm load and 100 watts in a 2 ohm load. Can you add a 4 ohm resistor to a single 4 ohm woofer in parallel to drop the load at the amp to 2 ohms thus increasing the output of the amplifier to the woofer?

Replies:

Posted By: DYohn
Date Posted: April 17, 2005 at 10:52 AM

Yes, you can add a resister and change the load on the amp, but NO it will not change the power used by the woofer. The woofer impedence will stay the same and it will continue to draw whatever it draws. The extra current being produced out of the amp will dissipate as heat in the resister. The only way to get more output is to add another woofer or use a larger amp (but even then you only gain approx. 3db with a second woofer, and it requires 10X the amplifier power to create twice the db volume.)

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Posted By: jeffchilcott
Date Posted: April 17, 2005 at 10:54 AM

unless you had a very very large resistor, most only handle 5 to 10 watts. you can add a device called an accumatch, but they really are not worth the money. you best bet it to buy an amp to match your sub

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