Audio Filter "highgain" mislabeled?

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cymansap
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Audio Filter "highgain" mislabeled?

Post by cymansap » Mon Jun 17, 2019 3:46 pm

Hi, so I was fumbling about with the the audio filters in Love and thought it was a little strange that there was no "cutoff" setting. So I messed with the settings a bit, and noticed that I am almost completely sure that the "highgain" setting actually controls the cutoff of the filter, however I assumed it referred to resonance. I even looked at the audio output in a frequency analyzer and was able to recreate the sound of changing """highgain""" of the love filter by changing cutoff of a filter in my DAW.

It seems misleading to call this "highgain", especially when calling it "Volume of high frequency audio"https://love2d.org/wiki/Source:setFilter

If it were up to me I would call these settings "lowcut" and "highcut" as they are referred to in the equalization effect. see:https://love2d.org/wiki/EffectType

Furthermore, using "bandpass" doesn't really get a bandpass effect unless you set both the "lowgain" and "highgain" to the same value. Only setting "highgain" gets a lowpass sound, and only setting "lowgain" gets a highpass sound. So why even have the filter type option? Couldn't you just use "bandpass" for everything? Just seems like another layer of complexity.

Sorry this is kind of rambley, I just thought that this part of love seemed counter-intuitive. It could at least be clarified in the wiki.

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zorg
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Re: Audio Filter "highgain" mislabeled?

Post by zorg » Mon Jun 17, 2019 6:10 pm

Löve gives you a relatively 1:1 mapping of what OpenAl(Soft) gives you in terms of audio effects.

That said, here's the developer/maintainer talking about this issue: https://github.com/kcat/openal-soft/issues/164

They do admit the filters are more akin to ~shelf filters instead of ~pass filters; That means, that modifying the high gain for a "lowpass" or the low for a "highpass" will modify the apparent cutoff frequency. (And both will vary the bandpass band centerpoint, even if it's not that noticeable)... i think, for the most part, i only skimmed it; that's why it works similarly to what you'd define an actual cutoff frequency (which is hardcoded)

Note that there's also no resonance/Q setting for them either.

In short, filters are limited if you want to use the OALS ones, but the terminology as given is fine.

I agree that the wiki on these things is a bit limited, but it can be openly edited... for the most part; graphical illustrations specifically to hard to get stuff like audio effects might be beneficial.

That said, you can create your own filters as i did in lua, Löve's performant enough for that kind of thing thankfully! :3

(And believe it or not, a few of us actually brainstormed a lot about the terminology that should be used for löve)
Me and my stuff :3True Neutral Aspirant. Why, yes, i do indeed enjoy sarcastically correcting others when they make the most blatant of spelling mistakes. No bullying or trolling the innocent tho.

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cymansap
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Re: Audio Filter "highgain" mislabeled?

Post by cymansap » Mon Jun 17, 2019 8:05 pm

Alright, apologies for my ignorance. It sounded like a pass filter, so i assumed it was a pass filter.

Thanks for the clarification, zorg!

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