Weird Ableton EQ Problem

T

Tone1304

Member
Joined
Jul 25, 2012
Location
Southend-on-sea
So i have my bass right and i wanted to cut the low end out so i grab my eq as usual and put a low cut on it, i noticed that the eq actually makes it clip after ive put the cut on it, whats this all about is the eq adding some kind of frequency information or something? In the first pic i have the low cut disabled and there is no volume clipping at all and in the second pic i turned it back on and it starts clipping, not really that important as i can just use gain staging to turn it down but i would like to know what causes this, i've noticed the auto filter does the same thing.

weird clip1.jpg
weird clip.jpg
 
Not entirely sure as the two spectra you posted are completely different in many ways (i'm guessing you didn't screenshot at exactly the same moment.

I've found very steep lowpass/highpass filters can have a similar effect to resonant ones in that they boost frequencies around the cutoff, something to do with phase relationships but not sure what. Try using a more gradually sloping filter
 
It's because the phase gets messed up around the cutoff point. It's like the number 2# reason people fuck up their sine-wave subs, since they add HP down there for no reason and the phase gets partially flipped on the way. Use a linear-phase eq = problem solved (at least the 95% of it).
 
Yeah I couldn't get the screenshot in the same place but the sound doesn't clip at all when its not applied and then clips when it is, I left the eq on in both pics so it proves it does nothing when the cut is by passed, I did also try using a more gradual slope but the same thing still happens
 
-agu- said:
It's because the phase gets messed up around the cutoff point. It's like the number 2# reason people fuck up their sine-wave subs, since they add HP down there for no reason and the phase gets partially flipped on the way. Use a linear-phase eq = problem solved (at least the 95% of it).
Click to expand...
So it's literally just a phasing issue then any linear eq plugins to recommend?
 
Ok I'll just have a little look around, I had a quick google search about what linear eq is and it explained that a normal eq actually delays the signal being effected a little bit this is why it phases, thanks for your help ☺️
 
I'm not a fan of linear phase EQs. I think they are designed to compensate for a problem that could be avoided much more easily just by not filtering so steeply.

Here's a couple of articles from people who understand more than me.

http://www.theproducerschoice.com/blogs/articles/5892301-linear-phase-eq-explained

http://www.rane.com/note115.html

I've always found a bog-standard 12db per octave to be the most transparent highpass or lowpass and I've never been bothered by those tiny bits of residual frequencies that don't completely get removed- but I have been bothered by random weird boosts when using steep filters
 
Last edited:
It indeed has to do with both the phase and the resonance around the cutoff point created by the steepness of the curve. See it like this, your EQ is nothing more than multiple filters in a serial setup. A standard lowpass filter will usually introduce a peak right at the cutoff frequency, the height of this peak is determined by the resonance or the 'Q' value. This in combination with the steepness of the lowpass filter itself might introduce a volume increase even when you are removing frequencies (and you would expect it to get quieter right?). So that is one reason why this happens, the other reason being that filters change the phase of sound to achieve the desired result, changing the phase of a sound could also introduce some volume increase.
 
Back
Top Bottom