[whistlebug23]

Hi all -

I was running some of my FLAC files through Spek when, for extra kicks and giggles, I put through the quintessential 192/24 Norah Jones. Now, I'm very much out of my league as soon as I open the box of signal processing (Nyquist & Shannon, eat your hearts out), but I thought these two bands at >75kHz (Fig 1) were interesting. I'm assuming this is an artifact of processing? Least of all, it's not like I'm going to have a 77.5kHz tone audibly ringing in my ears.

Some more observations:
The first band is very prominent on Lonestar (Fig 2).

The spectrum on One Flight Down is crazy, lots of blue and for some reason I think it looks like a David Finch film poster (Fig 3)...

The Long Day is Over has four bands, but I could be convinced it's only 3 (Fig 4). I also can't help but notice that the band(s) at ~32kHz increase in intensity between 0:20 and 0:45 (constructive interference? I haven't the foggiest idea!).

Anyway, hope you all think it's interesting too, and maybe I could learn something about signal processing while I'm here (but certainly not required).

Cheers,
Jake

P.S. In the same manner I have excessive 192/24 copies of Norah Jones, I also uploaded the largest possible version of the spectra.

Fig 1. Spectrum of Don't Know Why

Fig 2. Lonestar

Fig 3. One Flight Down

Fig 4. The Long Day is Over

 

[redrol]

This is typical high frequency electronic noise picked up during the recording... IE garbage.

 

[Roseval]

I always inspect files with a sample rate > 96 kHz.
Often you seen funny things, say the refresh rate of a CRT monitor etc.
I always downsample them to 96 kHz

Have a look at MusicScope, I do think it more informative than Spec
https://www.thewelltemperedcomputer.com/SW/AudioTools/Spectrum.htm

 

[whistlebug23]

Agreed, nothing of worth in those higher frequencies. I do think it's neat to see that stuff pop up!

I'm glad you mentioned MusicScope, I was looking into it, but wasn't sure of a trustworthy download source. I see where I'll be spending a lot of time...

 

[redrol]

Yeah but the program isn't going to change the fact that is high frequency noise.

 

[71 dB]

This is typical high frequency electronic noise picked up during the recording... IE garbage.

Settling to 44.1 kHz/16 bit saves from such ultrasonic garbage without loss of sound quality.

 

[redrol]

Settling to 44.1 kHz/16 bit saves from such ultrasonic garbage without loss of sound quality.

Exactly. Really all that needs to be said.