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<blockquote data-quote="AStovall" data-source="post: 7687671" data-attributes="member: 639368">Sort answer ..NoLong answerThe waveform dose not suddenly go square wave, Even when well into clipping you can still get AC content.This image is when i clamping my MB ref1.800&nbsp; note the RMS reading on the top of the meter, its AC coupled. Note the 5volt difference.<img src="http://img.photobucket.com/albums/v640/redzx2/20120228_120131.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /><img src="http://img.photobucket.com/albums/v640/redzx2/20120228_115942.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" />A DMM will only show you part of the picture. Im not a fan of DMM tuning ,becasue if you don&#039;t fully grasp whats going on you can do more harm than good.if you are going to use a DMM you need a precision high power resistor, or a clamp on current meter,when using the sub as a load. The sub will not be stable impedance when playing,its impedance will shift due to frequency,box rise,and heat making that silly formula every one like to throw around useless for this task.So you need a clamp on meter to read current ,so that you can calculate the impedance of the driver at your test frequency then you can calcualt weather or not you are at the amps rated output...but even then you can still be clipping but you will at lest be in the ballpark of you maxamum gain setting...at that frequency .&nbsp; &nbsp; You can use the formula only if you are using a known load such as a precision resistor...And even then you have to be very careful becasue as the resistor gets hotter&nbsp; resistance will drop or become a short if you cook the resistor which is a great way to explode fets and capacitors inside the amp.</blockquote>

[QUOTE="AStovall, post: 7687671, member: 639368"] Sort answer ..No Long answer The waveform dose not suddenly go square wave, Even when well into clipping you can still get AC content. This image is when i clamping my MB ref1.800 note the RMS reading on the top of the meter, its AC coupled. Note the 5volt difference. [IMG]http://img.photobucket.com/albums/v640/redzx2/20120228_120131.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v640/redzx2/20120228_115942.jpg[/IMG] A DMM will only show you part of the picture. Im not a fan of DMM tuning ,becasue if you don't fully grasp whats going on you can do more harm than good. if you are going to use a DMM you need a precision high power resistor, or a clamp on current meter,when using the sub as a load. The sub will not be stable impedance when playing,its impedance will shift due to frequency,box rise,and heat making that silly formula every one like to throw around useless for this task.So you need a clamp on meter to read current ,so that you can calculate the impedance of the driver at your test frequency then you can calcualt weather or not you are at the amps rated output...but even then you can still be clipping but you will at lest be in the ballpark of you maxamum gain setting...at that frequency . You can use the formula only if you are using a known load such as a precision resistor...And even then you have to be very careful becasue as the resistor gets hotter resistance will drop or become a short if you cook the resistor which is a great way to explode fets and capacitors inside the amp. [/QUOTE]

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