What does the exclemation mark left of the dB indicate?

[codingchipmunk]

Hello everyone,
I have always had issues with equalizers and PulseAudio, where increasing the loudness of frequencies led to distortion / scratching. The same happened when using the EQ from easy effects, only that - thanks to the status bar - I now know that this only happens when dB get positive. Also, easy effects shows an exclamation mark besides the dB when this happens.

So, independent of my audio issue, I would like to ask if the exclamation mark pops up if there is an actual issue with PulseAudio and / or its configuration or just shows up when dB are greater than 0 (unfortunately there isn't any tooltip on mouseover).

[wwmm]

or just shows up when dB are greater than 0

That is it. Before sending the signal to the sound card EasyEffects measures its level. This is what is shown in its bottom bar. If the level is above 0 dB the warning in the image is shown so the user can know the signal level is in a dangerous zone. It is in general fine to have the level above 0 dB in the other plugins level meters. But you do not want the output level in the bottom bar to get this high because this what your soundcard is going to get.

[wwmm]

And if all you want is too boost the bass a little it may be easier to just use the bass enhancer plugin instead of the equalizer that is harder to set properly.

[Fxzzi]

partially related, is there any way to see an estimated peak gain like is possible in EqualizerAPO on the bottom left? I'd like to prevent peaking with a few filters active, and want to get peak gain at 0dB

[wwmm]

is there any way to see an estimated peak gain

Peak gain of what exactly? We show at the bottom left the peak at the end of the pipeline. For individual plugins output level it is necessary to look at each plugin window.

[Fxzzi]

As equalizerAPO shows, it makes a calculation / estimate of the maximum gain your setup can reach, allowing you to set your preamp lower to account for it.

[wwmm]

As equalizerAPO shows, it makes a calculation / estimate of the maximum gain your setup can reach, allowing you to set your preamp lower to account for it.

Oh... I see. That can be a little complicated to do accurately. First because we handle many different plugins and the user is free to put more than one instance of each of them in the pipeline. Second because most of the plugins we use are third party plugins whose code and algorithm I am not familiar with. In APO the equalizer code is part of APO and not an external plugin. So they know the algorithm and can estimate things like these based on how the controls are set. Here I will have to find a mathematical model entirely through trial and error hoping its results would be good.

As this is not going to be done I suggest an alternative approach. Put the limiter plugin at the end of the pipeline and a level meter plugin right before it. Then use EasyEffects for some minutes with your usual workflow. The Level meter plugin will record the highest peak that went through it in the time window it was running. It is not the same as what APO is doing but it will give you an idea of how high the peak is getting. And with the limiter at the end the will be some protection in case something unexpected happens.