Discussion:
[Audacity-users] Plotting spectrum showing a blank screen
RT
2016-06-06 14:30:16 UTC
Permalink
I have a flac file that plays in vlc and audacity but when I go to -Analyze
- Plot Spectrum - the spectrum is a blank screen why is this.

It doesn't happen all the time but I have several files that do this.
Here's a link to one of the files.
https://www.dropbox.com/s/g2yhz2ttgcbmje4/A_000a_bitshift_000.00000_angleshift_deg_.flac?dl=0
Steve the Fiddle
2016-06-06 14:55:03 UTC
Permalink
It's because the left and right channel are exactly out of phase.
When Plot Spectrum analyzes a stereo track, it mixes the left and
right channels, then analyzes the mix. Because the channels are
exactly 180 degrees out of phase, the sum of the tracks (the mix) is
zero (silence).

To plot the spectrum of each channel separately, split the stereo
track into two mono tracks (from the track dropdown menu), then you
can use Plot Spectrum on one channel at a time.

Steve
Post by RT
I have a flac file that plays in vlc and audacity but when I go to -Analyze
- Plot Spectrum - the spectrum is a blank screen why is this.
It doesn't happen all the time but I have several files that do this.
Here's a link to one of the files.
https://www.dropbox.com/s/g2yhz2ttgcbmje4/A_000a_bitshift_000.00000_angleshift_deg_.flac?dl=0
------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
*********** ASKING FOR HELP *************
When asking for help on this list, please include the following information,
so we can
* What operating system you are using (for example, Windows XP or Mac OS X
10.5.1)
* Exactly what three digit version number of Audacity you are using (Help >
About
Audacity, or Audacity > About Audacity on a Mac computer)
* If this is a recording problem, what equipment you are recording with, and
how is it
connected to the computer?
https://lists.sourceforge.net/lists/listinfo/audacity-users
------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
*********** ASKING FOR HELP *************

When asking for help on this list, please include the following information, so we can
help you properly:

* What operating system you are using (for example, Windows XP or Mac OS X 10.5.1)

* Exactly what three digit version number of Audacity you are using (Help > About
Audacity, or Audacity > About Audacity on a Mac computer)

* If this is a recording problem, what equipment you are recording with, and how is it
connected to the computer?

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RT
2016-06-06 15:39:57 UTC
Permalink
thanks :-)
Post by Steve the Fiddle
It's because the left and right channel are exactly out of phase.
When Plot Spectrum analyzes a stereo track, it mixes the left and
right channels, then analyzes the mix. Because the channels are
exactly 180 degrees out of phase, the sum of the tracks (the mix) is
zero (silence).
To plot the spectrum of each channel separately, split the stereo
track into two mono tracks (from the track dropdown menu), then you
can use Plot Spectrum on one channel at a time.
Steve
Post by RT
I have a flac file that plays in vlc and audacity but when I go to
-Analyze
Post by RT
- Plot Spectrum - the spectrum is a blank screen why is this.
It doesn't happen all the time but I have several files that do this.
Here's a link to one of the files.
https://www.dropbox.com/s/g2yhz2ttgcbmje4/A_000a_bitshift_000.00000_angleshift_deg_.flac?dl=0
------------------------------------------------------------------------------
Post by RT
What NetFlow Analyzer can do for you? Monitors network bandwidth and
traffic
Post by RT
patterns at an interface-level. Reveals which users, apps, and protocols
are
Post by RT
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports.
https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
Post by RT
*********** ASKING FOR HELP *************
When asking for help on this list, please include the following
information,
Post by RT
so we can
* What operating system you are using (for example, Windows XP or Mac OS
X
Post by RT
10.5.1)
* Exactly what three digit version number of Audacity you are using
(Help >
Post by RT
About
Audacity, or Audacity > About Audacity on a Mac computer)
* If this is a recording problem, what equipment you are recording with,
and
Post by RT
how is it
connected to the computer?
https://lists.sourceforge.net/lists/listinfo/audacity-users
------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity
planning reports. https://ad.doubleclick.net/ddm/clk/305295220;132659582;e
*********** ASKING FOR HELP *************
When asking for help on this list, please include the following information, so we can
* What operating system you are using (for example, Windows XP or Mac OS X 10.5.1)
* Exactly what three digit version number of Audacity you are using (Help
Post by RT
About
Audacity, or Audacity > About Audacity on a Mac computer)
* If this is a recording problem, what equipment you are recording with, and how is it
connected to the computer?
https://lists.sourceforge.net/lists/listinfo/audacity-users
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