measuring 2.83 volts at amplifier? - AVS Forum
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post #1 of 6 Old 01-03-2012, 08:30 AM - Thread Starter
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Hello everyone,

When determining the SPL of a speaker at 1 meter at this voltage, do I measure the voltage at the amp while inputting a test signal before I hook up the speaker to it, or do I measure the voltage once the speaker is connected and the amp is under load?

Thanks,
John


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post #2 of 6 Old 01-03-2012, 08:35 AM
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Measure at the speaker terminals. You can have some voltage drop depending on your wire gauge and how long the cable is. Use a 50 or 60Hz sine wave as that is where volt meters are most accurate.


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post #3 of 6 Old 01-03-2012, 12:00 PM
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^^^ Assuming the speaker looks "nice" at that frequency... Ideally*, you'd use an RMS voltmeter with enough bandwidth to measure a number of points across the audio band. In practice, a spot check at 60 Hz is not unreasonable, although sensitivity is typically measured at 1 kHz. If your speaker's bandwidth does not extend to 60 Hz you may get a misleading result. Of course, you'll also get a misleading result if your DMM does not have 1 kHz AC bandwidth...

Either way, do it under load, as Ricci said. - Don

* Actually, "ideally" you'd use a wideband vector meter system to determine V, I, and power, but those are not cheap.

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post #4 of 6 Old 01-03-2012, 04:03 PM - Thread Starter
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Thanks, guys


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post #5 of 6 Old 01-04-2012, 06:58 AM
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Hey Don...I didn't mean that he should measure the SPL at 60hz. I guess it could've been read that way. I meant that should verify that he actually has the 2.8 volts delivered to the speaker that way. Then proceed to measure the speaker after he knows he has the right drive level.


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post #6 of 6 Old 01-04-2012, 11:18 AM
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Ah, I misunderstood, sorry! Makes sense. - Don

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