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JRSS Mixing - 5.1 to 4.0 Fantom Center at +3dB

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AGAWA:
Can you look at the following:
I'm using JRSS Mixing;
Have 4 speakers, therefore I downmix with JRSS form 5.1 to 4.0.
Just measured levels (using  internal calibration test). Fantom Center is produced at +3 dB.

Center signal level should be lowered to 0,707 before injection to FL and FR, thus creating 0 dB Fantom Center.

My suspicion is that it is not lowered.

AGAWA:
to be clear, I'm asking for verification of JRSS mixing algorithm;
my suspicion is that Center voltage level is not multiplied by 0.707 before injection to FL and FR.

+3dB is a result of mixing 100% of Center voltage into FL and FR

Matt:
I'm looking, but the code looks right to me:

// mix center into main sides
m_aryMix[0][2] += HALF_POWER_MULTIPLIER;
m_aryMix[1][2] += HALF_POWER_MULTIPLIER;

// factor in the center volume
m_aryMix[0][2] *= CDecibels::GetMultiplierFromDecibels(nCenterLevel);
m_aryMix[1][2] *= CDecibels::GetMultiplierFromDecibels(nCenterLevel);

Could the way you're measuring be at fault?  Or some other explanation?

Thanks.

AGAWA:
Tools -> Advanced -> Audio Calibration
There is 5.1 test

I'm using Radio Shack digital meter, set to 70 dB range;

Close to my head in my regular listening position; and FL and FR are 3 dB below Fantom Center
It should read about the same, +/- 1 dB.

Straightforward measurement

(equations: L'=L+0.707*C,R'=R+0.707*C,LS'=LS,RS'=LS.)

cheers

Matt:
I'm testing the 5.1 volume calibration clips outputting as 4.0.

My volume in DSP Studio > Analyzer is about -35.0 dB when playing the center.  It's about -35.0 dB when I play the left or right as well.

So that seems like it's working.

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