Re: [LAU] How is the bass mixed? Per-channel frequency analysis? Histogram?

On Wed, 5 Feb 2014 09:36:37 -0600
Matt Garman <matthew.garman@email-addr-hidden> wrote:

>
> I have a collection of FLAC files, all ripped from my CD collection
> What I would like to do is run an analysis across all the music to
> determine how the bass/lower frequencies are generally mixed. For
> example, how much content below (for example) 150 Hz is on the left
> channel versus the right channel?
>
> I'm not sure if "histogram" is the right word, but in my mind what
> I'd like to see, per-channel, is something like this:
>
> 150--125 Hz: x samples
> 125--100 Hz: y samples
> 100--80 Hz: z samples
> ...
>
> Then I can look at the two channels of a song, and if the histograms
> are approximately the same, I can assume the bass was mixed equally
> to both channels.
>
> I am a programmer, and thought it would be easy to quickly hack
> something up that would do this, but I have no experience with
> signal processing, and as I started reading about this, I quickly
> got in over my head! So I was hoping there might already exist a
> tool that has this functionality.

One thing to note: According to my understanding you won't get accurate
sample counts here. To do frequency analysis you'll need to look at a
bunch of samples at a time. Typically you'll use some sort of Fourier
transform. So your granularity will be limited by the window size I
guess. I don't think this is very important in this case though, but
maybe it gets you on the track.

> Note that I don't need any kind of graphical output, as this needs
> to be wrapped up in some kind of batch processing script---I have
> about 11,000 files to analyze!
>
> The motivation for this is: I have a hardware DAC (digital audio
> converter) in one part of my house, and a subwoofer in another.
> There is a single coax run between the DAC and subwoofer, so I can
> only send one channel. If the overwhelming majority of my music has
> the bass mixed equally, sending only one channel isn't a problem.
> But if I choose the "L" channel to send to the sub, and much music
> has the bass mixed only to the "R" channel, then I won't be able to
> hear the low frequencies. I want to find out how often this might
> happen.
>
> Thanks,
> Matt

Can you mix the bass channel to mono? That would be the simplest
solution.

Regards,
Philipp
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Received on Wed Feb 5 20:15:03 2014