Spectrum Analysis - Scale?

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Babak
Posts: 8
Joined: Fri Jul 11, 2008 6:24 pm

Spectrum Analysis - Scale?

Post by Babak »

Hello

I want to analyze a sound file, but the scaling is a little awkward.

If I choose the spectrum size of 65k points (one extreme), I get a spectrum between 0 Hz and 150.000 Hz (see http://www.abload.de/img/spektrum1szy.tiff)

If choose the size of 512 points, and I zoom in in the settings, I get a spectrum between 0 and 20.000 Hz. (see http://www.abload.de/img/spektrum2ixk.tiff)

Bute I would like to zoom in further, but there is not much room for that (see http://www.abload.de/img/scaleghi.tiff)

If I take the slide to the other side, the spectrum would reach up to 200.000 Hz (see http://www.abload.de/img/spektrum3lrn.tiff) !!!

Who needs those frequencies? ;)

How can I zoom in further?

Cheers

Babak

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Lou Kash
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Post by Lou Kash »

I've noticed this issue today, too. To me it looks like a bug...

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Martin Hairer
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Spectrum Analysis - Scale?

Post by Martin Hairer »

If I choose the spectrum size of 65k points (one extreme), I get a
spectrum between 0 Hz and 150.000 Hz (see http://www.abload.de/img/spektrum1szy.tiff)
There's something wrong there. A spectrum with 65000 points would
never look like this. Can you reproduce this and are you absolutely
sure that you selected 65000??
If choose the size of 512 points, and I zoom in in the settings, I
get a spectrum between 0 and 20.000 Hz. (see http://www.abload.de/img/spektrum2ixk.tiff)

Bute I would like to zoom in further, but there is not much room for
that (see http://www.abload.de/img/scaleghi.tiff)

If I take the slide to the other side, the spectrum would reach up
to 200.000 Hz (see http://www.abload.de/img/spektrum3lrn.tiff) !!!
Well, the spectrum is cut off at about 20'000 Hz. Anything beyond that
is zero. The only reason why you see it is because you choose to do
so.... There is no bug here but maybe some misinterpretation of how a
spectrum analysis works. What exactly are you trying to achieve?
Regards,

Martin

HairerSoft
http://www.hairersoft.com/


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Lou Kash
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Post by Lou Kash »

Perhaps not a bug, but the zoom of the Spectrum window is not very intuitive to use. Once you have zoomed in, it's very hard to zoom out to a view which I - and obviously also Babak - would expect.

Possibly there's a window redraw bug...? The issue has something to do with the horizontal scroll bar and its position as well as with the size of the window. It probably shouldn't zoom out more than the highest available frequency.

Anyway, after some experimenting I guess I figured out the trick how to zoom out while getting rid of the unnecessary frequency scale...

Babak
Posts: 8
Joined: Fri Jul 11, 2008 6:24 pm

Post by Babak »

Hallo

Thanks for the replies.

What I want to achieve is to analyze, whether low frequencies are present in the sound file, especially those below 100 or 50 Hz, respectively.

I am shure, I chose 65000 in the setting.
With that setting the only correlation I see is that the frequency range besomes much large, up to some 100 kHz, as can be seen on the screen shots.

Cheers

Babak

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Martin Hairer
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Spectrum Analysis - Scale?

Post by Martin Hairer »

I am shure, I chose 65000 in the setting.
With that setting the only correlation I see is that the frequency
range besomes much large, up to some 100 kHz, as can be seen on the
screen shots.
That's bizarre. In principle, choosing a larger number of samples does
improve the resolution at low frequencies, so this is what you should
be doing. Now when I use the settings shown in

http://www.hairersoft.com/Downloads/settings.png

I obtain something like what is shown in

http://www.hairersoft.com/Downloads/spec.png

Note that you can clearly see the low frequencies in this picture.
Regards,

Martin

HairerSoft
http://www.hairersoft.com/


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Babak
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Joined: Fri Jul 11, 2008 6:24 pm

Post by Babak »

Hello,

I deinstalled the software, downloaded the most recent version and installed it again.

Same problem.

The spectrum goes up to 250 kHz when 65k data points are selected.

That's really bizarre.

What can I do here?
It worked up to one of the updates (I don't know which one it was).

Cheers

Babak

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Martin Hairer
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Spectrum Analysis - Scale?

Post by Martin Hairer »

What can I do here?
Try maybe to trash the preferences file? It is located in

Library/Preferences/com.HairerSoft.AmadeusPro.plist

Regards,

Martin

HairerSoft
http://www.hairersoft.com/


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Babak
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Post by Babak »

Hello,

thanks for the hint, but there is no file rearding Amadeus or hairer in the preferences folder.

Cheers

Babak

padmavyuha
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Post by padmavyuha »

That should be:

~/Library/Preferences/com.HairerSoft.AmadeusPro.plist

where ~ is your home folder - these prefs are in the user library, not the system/main one.

- padmavyuha

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Martin Hairer
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Spectrum Analysis - Scale?

Post by Martin Hairer »

A follow-up on this one. I think that the problem was caused by a
mistake in the German translation, this is why I couldn't reproduce it
earlier. I just updated the German locale in the archives on my
website, so if you download it again it should work now. Cheers,

Martin

HairerSoft
http://www.hairersoft.com/


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Babak
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Post by Babak »

Hello

sorry for answering so late.

I downloaded the new version and also trashed the preferences.
And it works!

Thanks to everybody!

:D

Cheers

Babak

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