Frequency of THX intro

[burdette]

There is a THX speaker test on some DVDs... it plays a tone through each of the speakers in turn (Toy Story has it). Does anyone know the frequency of the subwoofer tone used in this test??

I can hear and feel the tone through my Monitor 7Cs, and was just wondering what frequency I was getting.

Thanks.

[HBombToo]

Are you referring to the Pink Noise measurement?

[HBombToo]

I found this on the Net. should help clear things up a bit.
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The characteristics of pink noise
For the purposes of this discussion, "power" means the average power or energy contained in a signal over a long period of time.
White noise has the same distribution of power for all frequencies, so there is the same amount of power between 0 and 500 Hz, 500 and 1,000 Hz or 20,000 and 20,500 Hz.

Pink noise has the same distribution of power for each octave, so the power between 0.5 Hz and 1 Hz is the same as between 5,000 Hz and 10,000 Hz.

Since power is proportional to amplitude squared, the energy per Hz will decline at higher frequencies at the rate of about -3dB per octave. To be absolutely precise, the rolloff should be -10dB/decade, which is about 3.0102999 dB/octave.
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HBomb

[Dr. Spec]

The THX test tone generator subwoofer tone is centered at about 40 Hz, but contains some harmonics above and low that.


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