Frequency Analysis: Sub 20Hz Frequencies Shown Across All Files

Report · Jan 09, 2017

Hello,

I am running Audition CS6 in Windows 7 Professional 64 bit on an HP dv7-7000 Quad Core Edition laptop. All audio files show a bump below 20Hz in the Frequency Analysis window. This occurs across all files, no matter the source, i.e., personal recordings, ripped Cds, etc.

Here is an image using a CD file:

What could be causing the noise below 20Hz? This occurs on any file type, no matter whether I'm using the laptop's sound card or a USB audio interface.

Any comments and suggestions are greatly appreciated.

Thank you,

Eric

Report · Jan 17, 2017

There was a 5.0.2 bugfix release for Audition CS6... is this the version you are running, or 5.0.1?

Report · Jan 17, 2017

It's Version 5.0.2 - Build 7. Besides the aforementioned being odd, there's this too. The Tascam US2000 interface shows 24 bit/88.2kHz, but the Line-In Properties in Windows 7 only shows a 16 bit setting. There are scant interface controls in Audition Preferences:

Is this a big deal, as my recorded test files are shown by MediaInfo to actually be 24 bit/88.2k? Is Windows down sampling from 24 bit to 16 bit for monitoring? Could any of this have affected my FFT analyses of low frequency signals?

Report · Jan 18, 2017

Eric Holtz wrote:
Is this a big deal, as my recorded test files are shown by MediaInfo to actually be 24 bit/88.2k? Is Windows down sampling from 24 bit to 16 bit for monitoring? Could any of this have affected my FFT analyses of low frequency signals?

If you are using an ASIO driver, then Windows isn't getting to it at all; the whole purpose of ASIO is to bypass any of its potentially unpleasant effects - like re-sampling, and generally slowing everything down. FFT analysis operates independently of anything that Amplitude Statistics does, and my guess is that it's the latter that is operating incorrectly. And I have to say that Amplitude Statistics has got form when it comes to this - it's been hit by bugs before.