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Author Topic: DSP Analyzer and db level. ISSUE  (Read 1230 times)

luckyaua

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DSP Analyzer and db level. ISSUE
« on: May 08, 2015, 01:33:07 pm »

I think there is an issue with level of DSP analyzer:
if i play a -20db sine wave stereo track the draw level of the curve left and right channel is the same and the total level (orange curve) is +3db so it's ok but the level reported in db on the upper left corner is the same for all curve (-23db) why?
the level of total curve should be -20db!!

So another question...i believe that each horizontal line represent a 3db increment and the scale is 50Db (from 0 to -50db) but it seem referred to a single channel level not for the total level infact if i play a 0db sine wave the yellow and blu lines are at the top instead the orange is over the  range...why?

at the end i think that is useful to have a db label for level on the left axis. ;)
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luckyaua

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Re: DSP Analyzer and db level. ISSUE
« Reply #1 on: May 09, 2015, 11:25:30 am »

nothin 4 me? ?
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mwillems

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Re: DSP Analyzer and db level. ISSUE
« Reply #2 on: May 09, 2015, 12:32:43 pm »

The 3dB issue is a common issue with sine wave test clips. A "-20dB sine wave" could be a -20dB RMS sine wave or a -20dB peak level sine wave.  If it's a -20dB peak sine wave the analyzer would correctly show a -23dB RMS level as the RMS level of a sine wave is 3dB lower than its peak.

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luckyaua

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Re: DSP Analyzer and db level. ISSUE
« Reply #3 on: May 09, 2015, 12:55:55 pm »

ok but if the 3 curves are rappresented with left and right same level and both + 3db i think that alspo the level repsented with number (top left) must show same level for left/right and +3db fot both but the tree value is the same!?!?!?
this is the screenshot for a 100Hz sine wave art -20db.
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blgentry

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Re: DSP Analyzer and db level. ISSUE
« Reply #4 on: May 09, 2015, 08:11:52 pm »

Maybe the overall volume level is an average of left and right?

Brian.
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