Changed behavior of graphic equalization in 2.0.3

[Paul L]

I notice in 2.0.3, if I use the graphic view of equalization, the sliders do not retain their exact positions between uses, as they did in 2.0.2. Some sliders adjacent to those I intentionally moved get moved too, after I apply the effect, then call up the dialog again. What's going on?

[Gale Andrews]

Thanks for the report.

We do have a few reports of unpredictable behaviour in Equalization in 2.0.3, but not specific to the Graphic EQ Mode.

Please give us more details.

• Have you saved extra preset curves?
• Have you imported extra preset curves?
• Do you see numerous "unnamed(n)" curves (where (n) is a number) in the "Select Curve" list?
• What language are you running Audacity in?
• Please also state your exact operating system (see the pink notice above). Are you still on Windows 7 as I found in one of your other posts?

Depending what the problem is, you may be able to stop it happening by renaming EQCurves.xml
and EQBackup.xml in the Audacity folder for application data to other names. See here for that folder's location: http://manual.audacityteam.org/o/man/pr ... tml#stored .

Renaming those files will stop Audacity seeing any custom curves that you have, but while Audacity is quit you could add those custom curves back to EQCurves.xml (making sure you preserve the correct syntax of open and closed tags) and see if that fixes the problem.

If you can provide any exact steps to reproduce the problem in the form 1, 2, 3... please do so.


Gale

[Paul L]

I thought that the bug would be a mathematical thing not specific to operating system, but who knows. Yes, I am using Windows 7. Sorry if I'm not honoring proper procedure.

Now that you mention, the few preset curves I added and was accustomed to using in 2.0.2, do not look the same now. I had a certain simple curve that pushed all sliders in a certain range down and none others at all -- it reloads with sliders in in-between positions.

But I can see this effect even with ad-hoc curves. For instance, choose 8191 for length of filter, B-spline curves. Push 20Hz all the way down and 20kHz all the way up. Apply that to something with OK. Call up the dialog again. What do you see? I see this in 2.0.3, whereas in 2.0.2 I would see exactly what I saw before dismissing the dialog.

Seems like some interpolation is happening that is unlike the green curve I see when setting the sliders?

[steve]

It looks to me like a bug has crept in between Audacity 2.0.2 and 2.0.3.
I'm seeing some peculiar behaviour where the Eq curves are recalculated when switching between "graphic" and "draw curves" modes.

An easy way to reproduce the issue (tested on Linux and Windows XP):

1) Open Equalization in Graphic mode.
2) "Flatten" the settings, then pull down the 1000 Hz slider to minimum (-20 dB).
3) Switch to "Draw Curves" mode, then back to "Graphic" mode.

In Audacity 2.0.2 the Eq settings are as in step 2.
In Audacity 2.0.3 the Eq settings have changed (the 800 Hz and 1.25 kHz sliders have moved down to -2.6 dB and the 1kHz slider has moved up from -20 to -15 dB).

This issue dates back to at least r12100 (Dec 31st 2012).
In r12092 there is a problem with Eq curves, but it is different - the curve in "Draw Curve" is not drawn.

There are a whole bunch of updates between r12093 and r12100 that do not build on my Linux machine so I'm not able to narrow this down much more.

The last version that worked correctly seems to be r12076.

[Gale Andrews]

I thought that the bug would be a mathematical thing not specific to operating system, but who knows. Yes, I am using Windows 7. Sorry if I'm not honoring proper procedure.

You are probably correct this particular issue is not operating-system specific but we still strongly prefer everyone who thinks they have found a "bug" to post to the board for their operating system. We must know the operating system as a fundamental element in any bug report.

We can't really have a "bugs" board here because it would become unmanageable. Most items reported as "bugs" would of course not be any such thing and then we would not even know the operating system the user was on to try and help them.

Alternatively, bug reports can be sent to our feedback address .

Thanks again for the report.


Gale

[Paul L]

An important question would be this: if Audacity changes the curve that I specify, then when I use the sliders the first time and apply the effect, is it really applying my curve or the changed curve? The fortunate answer is, my curve.

Experiment convinces me of this. Just record a noisy breath and look at in linear spectrogram with vertical scale all the way to 22k: it's bright in all frequencies so you can see what is really being changed.

And if I undo, and then reapply the affect with ctrl-R -- then again, it appears to be the correct effect.

Only when you call up the dialog again is the specified curve misremembered, and then that other curve will be applied if you hit OK.

[steve]

An easy way to test the Equalization settings is to apply it to white noise (Generate menu > Noise) and then look at the result of the equalization using "Analyze > Plot Spectrum".

An important question would be this: if Audacity changes the curve that I specify, then when I use the sliders the first time and apply the effect, is it really applying my curve or the changed curve? The fortunate answer is, my curve.

Yes, the problems occur when loading curves or changing between Draw and Graphic modes. If you simply make settings in either the Draw or Graphic mode, then as long as you don't change to the other mode the equalization will be correct.

The bug has been logged, and currently has "P2" priority (the second highest priority), so it should be fixed in the next Audacity release.

[Paul L]

This bug might be bad news for anybody using an equalization curve in a chain.

[steve]

Not good news for blind users either as they won't be able to see the clues of when it has gone wrong.
In fact, not good news for anyone.
Fortunately at least part of the cause is known, so it should be fixable, though probably beyond my very limited abilities in C++ to fix.