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figuring RMS

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=32377
Printed Date: May 01, 2024 at 5:16 PM


Topic: figuring RMS

Posted By: doc t
Subject: figuring RMS
Date Posted: May 19, 2004 at 6:26 AM

  I know I've seen a thread about this in the past...but can't find it now...What is the best and most sure fire way to figure out how many WRMS a low end amp puts out, if it only gives you max wats, peak output?




Replies:

Posted By: stevdart
Date Posted: May 19, 2004 at 9:01 AM
Similar to the thread you referred to, you can use your multimeter to read output voltage.  Power in watts = voltage squared / ohms resistance.  Refer to Ohm's Law calculations to find power.  Read with test tones for a steady volt reading.  But the sure-fire way is this, if you have an oscilloscope and all this stuff to work with.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.




Posted By: haemphyst
Date Posted: May 19, 2004 at 9:07 AM
multiply the input fuse value by 14.4, divide by 4. this assumes a 50 percent efficiency. example: 20amp fuse x 14.4 = 288 / 2 = 72 watts RMS per channel (engine runing. multiply by 12 for engine off ratings). this'll get you close to a real output value. double that number, will give you close to a peak, low distortion (>10 percent distortion) output.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."




Posted By: doc t
Date Posted: May 19, 2004 at 9:25 AM
and to find bridged rms values just multiply rms output for two ch. by 2. ex: 72x2=144 bridged rms?





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