RMS Metering Discrepancy in Sonar and Sound Forge

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jsg
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2008/04/17 14:06:54 (permalink)

RMS Metering Discrepancy in Sonar and Sound Forge

When I set my metering in Sonar 7 (bus meters) for RMS, and open that same file in Sound Forge, the RMS metering is wildly off. Whereas I'm getting values around -18 to -12db RMS in Sonar, Sound Forge is showing +2 to +6. I have tried various metering options, but the large difference remains.

Any experts here that can shed light on this?

Thanks in advance,

Jerry Gerber
www.jerrygerber.com
#1

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    Schlep_Math
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/17 17:00:20 (permalink)
    Just mentally add a 1 and substitute the + for - in front of the numbers you see in Sound Forge and you should be in the ballpark.



    But no, seriously.
    I have no clue.
    Someone else?
    post edited by Schlep_Math - 2008/04/17 17:18:54

    #2
    altima_boy_2001
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/17 17:59:51 (permalink)
    Test it using a sine wave or any other wave form that will give a consistent value. Most likely they will give a consistent difference between the two applications. My guess is that Sound Forge is giving RMS values relative to some value (maybe set in the options?). Also, small variances may result from apps using different window sizes (number of samples) to derive the average at any instant, but when taken over the same range they should give the same results.

    Some applications will differ by 3 dB since 0 dB RMS can be defined by the RMS value of a full-scale sine wave vs a full-scale square wave. AES says RMS of a full-scale sine wave will be 0 dB RMS others like Sonar say it is -3 dB RMS (the mathematical result). AES says a square wave will be +3.01 dB RMS and a Sonar says it will be 0 dB RMS. Just remember that anyone using the AES standard will give RMS values that are 3 dB higher, but everyone will agree on peak dB values.
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    jsg
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/17 21:18:37 (permalink)

    ORIGINAL: altima_boy_2001

    Test it using a sine wave or any other wave form that will give a consistent value. Most likely they will give a consistent difference between the two applications. My guess is that Sound Forge is giving RMS values relative to some value (maybe set in the options?). Also, small variances may result from apps using different window sizes (number of samples) to derive the average at any instant, but when taken over the same range they should give the same results.

    Some applications will differ by 3 dB since 0 dB RMS can be defined by the RMS value of a full-scale sine wave vs a full-scale square wave. AES says RMS of a full-scale sine wave will be 0 dB RMS others like Sonar say it is -3 dB RMS (the mathematical result). AES says a square wave will be +3.01 dB RMS and a Sonar says it will be 0 dB RMS. Just remember that anyone using the AES standard will give RMS values that are 3 dB higher, but everyone will agree on peak dB values.



    That is what I did, used a sine wave and compared Sonar with Sound Forge. Adjusting for Sound Forge's options, the closest I could get the RMS values of Sonar and SF was Sonar at around -14dB RMS and SF around 1dB RMS, a difference of 15dB! The peak values are exactly the same. Thanks for your input. The thing is, my values are not different by 3dB, but a lot more, even though both programs express -10dB for the peak values of a steady sine wave at 440cps. Doesn't make a lot of sense. If I try other Sound Forge metering options, the difference gets even greater! I used a 10 second sine wave sample, which should be long enough time to get an accurate RMS value.

    Best,

    Jerry Gerber
    www.jerrygerber.com
    #4
    Silence Dogood
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/18 08:58:15 (permalink)
    Anybody got any ideas? (tht)

    If at first you don't succeed, keep sucking 'till you do succeed! ("Curly" Howard)
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    Desperate Dan
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/18 09:08:31 (permalink)
    Anybody got any ideas? (tht)

    Yeah, the same guy that wrote the CPU Meter code wrote the Audio Meter code, both suck. CPU meter Doesn't even match it's own other cpu meter in the Traansport Bar, both are drastically different on my setup and both are different to the Windows CPU Usage.

    Windows 7 Professional  64 bit - Intel Q-9550 2.83 CPU, 8Gb DDR800, Gigabyte EP35-DS3R, M-Audio Delta 44, Yamaha HS-80M Monitors, UAD-1 Ultra Pack

    I'm reading a book about anti-gravity at the moment and I just can't put it down
    #6
    AJ_0000
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    RE: RMS Metering Discrepancy in Sonar and Sound Forge 2008/04/18 11:54:46 (permalink)
    One thing you can check is pan law settings in Sonar. Changing it to -3 center might make some difference.
    #7
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