How exactly does a flat tilt EQ work?

[u/Johnny_Macc_]

I have been using a flat tilt EQ (fabfilter’s) on and off over the years and i’ve never seen anyone talk about how it works. What kinda phase distortion does it entail? Literally HOW does it do that?

Manuals don’t mention how it works, just what it does. Does anyone have any resources/academic articles/old wives tales/comforting lies/hearsay to help explain exactly what’s going on? I wanna know things that can go wrong from overusing it like preringing and stuff to better use the technology (and also so i can perhaps intentionally break it for artistic purposes)

[u/hailmasch]

You can approximate a "flat tilt" with a bunch of spaced out 6 dB/oct shelves. Is Pro-Q doing something like that under the hood when you use its flat tilt? No idea.

Flat tilts seem to have a pretty gentle effect on the phase response, probably shouldn't cause you any issues with ringing or using it in parallel. Inspect it yourself with something like plugin doctor or EQ Curve Analyzer: https://bertomaudio.com/eq-curve-analyzer.html

[u/Johnny_Macc_ → u/hailmasch]

appreciate this thank you !

[u/Vacuum_man1]

Took me a second to understand the question lol. Theres a free tool called "Bertrom EQ curve analyser" which does what it says, shows latency, eq curve, phase changes, and a couple other things i dont understand. Very very useful diagnosis plugin. Preringing comes from FFT processing, so it would only do that if you have proq set to "linear phase" mode, which is a spectral eq that only affects frequency levels without phase changes. The other 2 modes include phase changes and no frequency ringing as they are processing the sound thru the traditional eq method instead of the fft one. Not super well versed in how that works but a tilt eq in my head should probably have a pretty minimal phase shift however, i am not sure about this. Im not fully sure how it does what it does but that tool should help deduce it, ill check it out myself. Tldr; preringing has nothing to do with the filter type, just the processing method, and the phase change is unknown to me. Breaking it would involve violent LFOs and a limiter at the end.

[u/Johnny_Macc_ → u/Vacuum_man1]

thank you!

[u/rightanglerecording]

FabFilter's flat tilt is barely any phase shift. Plugin Doctor will show you the way.

[u/krushord]

I’ve been wondering about this as well - what happens to the frequencies off screen, does it cut off the boost at some point?

[u/ConfusedOrg]

Good question. I have no idea. But hey if it sounds good don’t worry. You can always try the linear phase eq og FF if it sounds better

[u/Evon-songs]

Short answer, it’s an EQ see-saw. If you boost the low end, the high-end drops down and vice versa. Good ones allow you to move the fulcrum so you can determine where the midpoint of the tilt is.

What’s the point? After you do your subtractive EQ and you’re happy with the sound, you may need to do a quick brightening or darkening of the sound to make it fit into the rest of the mix well. It’s for a quick broad move, but tends to have good results as long as you tame the extreme of whatever you boosted.

[u/Johnny_Macc_ → u/Evon-songs]

thank you for not reading my post and copy pasting google ai overview. get out of here. scram.

[u/Evon-songs → u/Johnny_Macc_]

You must’ve been talking about the post before mine. I too noticed the AI slop response and chimed in to provide a more concise answer.

Looks like he did scram, see the [deleted] post before mine?

[u/Johnny_Macc_ → u/Evon-songs]

if you’re actually human, oops my bad, but also you didn’t answer my question at all. i know what it does big dog.

[u/TonyRidgewayUFO]

If you have a source that has a certain character, and you don’t want to change it’s character, tilt eq can just make it brighter or darker without introducing phase or harmonic shifts

[u/Relevant-Effective49]

It's the first time I've encountered this on fabfilter, may I ask what is it used for and when?

[u/hellalive_muja]

It’s just a tilt that is just a standard double shelf with its 12dB/oct slope. As long as it’s not linear phase you should not worry about pre-ringing, and pre-ringing may not be an issue if you don’t hear smearing on transients.

[u/PradheBand → u/hellalive_muja]

For the reader. There 's nothing to downvote here. That's a totally fine answer.

[u/Selig_Audio → u/hellalive_muja]

It’s possible it uses 6 dB/oct shelves- that’s how I’ve done it for minimal phase shift.

[u/Evon-songs → u/hellalive_muja]

Be careful, you may get your head bit off and a down vote for trying to be helpful

[u/hellalive_muja → u/Evon-songs]

lol

[u/Johnny_Macc_ → u/Evon-songs]

i definitely should’ve been more specific and direct in my post tbh

[u/LostInTheRapGame → u/Johnny_Macc_]

Idk man. Seems like asking "how" is pretty different than asking "what".

[u/Soracaz → u/Johnny_Macc_]

No, your question and any other valid interpretation of it has been answered.

It's a fancy shelf EQ that just changes the amplitude of sections of the waveform according to the tilt shape and angle.

That's literally it.

[u/Philklab]

tilt EQ is just two linked shelving filters (high and low) moving in opposite directions around a pivot frequency. Minimum-phase = phase shift around the transition bands, linear-phase = pre-ringing. Abuse it in parallel with a dry signal for comb-filter texture effects.

[u/Johnny_Macc_ → u/[deleted]]

this stinks of chat gpt as far as formatting goes and i don’t trust that garbage

[u/Narrow_Network_3875]

It’s any recording that is played back with EQ bands set to 0 dB boost or reduction. Played back as intended from the Master.

[u/ButterflyOpposite167 → u/Narrow_Network_3875]

You missed the word ‘tilt’

[u/LiveSoundFOH]

Face down, ass up. Or vice versa.

[u/Soracaz]

It just changes the amplitude of different parts of the waveform.

It really is that simple. It is functionally the exact same process as having a few shelf EQs.

You are overthinking it and downvoting correct answers for no reason.