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Trying to figure out how many watts are reaching speakers

 
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Old 02-26-2016, 05:46 PM
ep120794
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Default Trying to figure out how many watts are reaching speakers

So I have a working system that has a 4 channel amp bridged running the front speakers and a second 4 channel amp bridged running the lid speakers. The amps are tucked deep into the space between the fairing and glove box on my Road Glide so I can't get to the speaker outputs easily. I wanted to just do a quick test with the DMM to see what voltage was reaching my speakers. I removed both the pos and neg spades from my front right speaker and removed the neg spade from my front left speaker. I put in the 1000 hz tone and put the pos dmm lead to the pos spade and the neg dmm lead to the neg speaker spade. I got a reading of 40 volts at 75% volume. In order to use the v=sqroot(r*p), do I have to divide the 40 in half because the 4 channel amp is bridged? Again the goal is to try to figure out how many watts are reaching my 4 ohm speakers.
 

Last edited by ep120794; 02-26-2016 at 05:51 PM.
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Old 02-26-2016, 07:07 PM
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What are the 2 amps?
 
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Old 02-26-2016, 07:17 PM
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Both are SS PN41000D
 
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Old 02-26-2016, 07:21 PM
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Gains are just shy of 10:00 o'clock. It sounds great, but I just want to figure out what the speakers are seeing.
 
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Old 02-26-2016, 07:42 PM
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Did you manage to get both of these in the fairing? Also curious what speakers your driving with them. This system should be screaming.
 
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Old 02-26-2016, 07:49 PM
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Are you measuring your voltage as AC or DC? It needs to be measured as AC, also need to know if you are measuring it as Volts RMS, Volts peak, or Volts peak to peak at 1kHz.
After you figure out how you're measuring it, then I can convert it to watts, but I will still need to know your speakers impedance at 1 kHz.
 
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Old 02-26-2016, 07:53 PM
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Measuring at AC at the 200 setting on the Dmm
 
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Old 02-26-2016, 11:43 PM
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40 volts into a 4 ohm impedance at 1 kHz = 400 watts, into 2 ohms it would be 800 watts.
 
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Old 02-27-2016, 01:59 AM
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Still having trouble believing I am really seeing 400 watts at the speaker with the gains just below 10 o'clock.......hmmm
 
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Old 02-27-2016, 08:57 AM
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Originally Posted by ep120794 View Post
Still having trouble believing I am really seeing 400 watts at the speaker with the gains just below 10 o'clock.......hmmm

The gains are a voltage adjustment.
 

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