Low Shelf vs. High Pass EQing

[JerGoertz]

When would you use one vs. the other? They seem to be for similar purposes.

[fese]

With a low shelf, you have more control over the amount of gain reduction below the frequency, and everywhere the same amount, the hi pass cuts continuously reduces the gain below the frequency by a specific amount per octave.
So you would use a hi pass on tracks where you e.g. want to really remove the low frequency content (because it is non musical noise or rumble), and the low shelf on signals, where you actually want to keep the low frequencies but they are a bit too strong.
Example: on a (badly) recorded acoustic guitar you could use a hi pass (I prefer the term “lo cut”) at say 70Hz to remove non relevant rumble, as the low E on a guitar is at ~80 Hz , nothing really relevant to the sound of the instrument there. Then you could apply a low shelf at maybe 200-300Hz to reduce the general boominess (because someone pointed the mic too close to the sound hole), but you don’t want to completely remove below that as it is musically relevant information.

[fese]

...and once again I clicked”quote” instead of edit...

[JerGoertz]

With a low shelf, you have more control over the amount of gain reduction below the frequency, and everywhere the same amount, the hi pass cuts continuously reduces the gain below the frequency by a specific amount per octave.
So you would use a hi pass on tracks where you e.g. want to really remove the low frequency content (because it is non musical noise or rumble), and the low shelf on signals, where you actually want to keep the low frequencies but they are a bit too strong.
Example: on a (badly) recorded acoustic guitar you could use a hi pass (I prefer the term “lo cut”) at say 70Hz to remove non relevant rumble, as the low E on a guitar is at ~80 Hz , nothing really relevant to the sound of the instrument there. Then you could apply a low shelf at maybe 200-300Hz to reduce the general boominess (because someone pointed the mic too close to the sound hole), but you don’t want to completely remove below that as it is musically relevant information.

Thanks, that makes sense.

[vitocorleone123]

Depends a lot on genre, too.

Cutting out the bass on a lot of things can lead to a very weak and unnatural sounding track. In electronic music, if you then fill that hole with a massive bassline and kick, that's probably OK. In a rock band, that might sound cheap and unprofessional.

A lot of times a low shelf will do the trick just fine, or even a shelf with a cut down further than it otherwise would be to still remove really low bass. Carving out notches (bell) can also help other instruments sit together better. Cymbals probably don't need low frequency information down at 60Hz... but that's not a hard rule, because maybe you have a giant gong/crash sound and everything else is silent - by removing all the low end, it'll might sound harsh and lame.

[MogwaiBoy]

I think your logic sounds totally on-point to me.

High pass filter = cut junk (ie: LF rumble / DC offset)
Low shelf = reduce bass frequencies (general instrument use)

It is upto your discretion, because even low frequency rumble in a piano might seem like junk but it still provides a weight and "air" down there that can help bring realism.

I wouldn't heed the advice from EDM producers about high-passing almost everything, multiple times, every instrument, every bus including the master and then again in mastering. But there is definitely something to be said about free'ing up space for bass and kick, if you're making music with those elements.

[JerGoertz]

Thanks guys, very helpful advice for me! I am really getting into mixing now and am trying to absorb useful info like a sponge.

[meloco_go]

Thanks guys, very helpful advice for me! I am really getting into mixing now and am trying to absorb useful info like a sponge.

Don't try to be too rational about it, experiment more. Low-shelves can also be surprisingly effective for cutting frequencies. Most importantly, the trick is to decide whether you want to attenuate or completely remove the low-end. Use your ears and bypass button!

[TIMT]

I tend to stick with shelves because i don't like the amount of phase rotation and group delay more effective highpass filters introduce.screwing with the phase too much on key elements can initiate the dog chasing its tail scenario,so good to keep it mind from the word go.one effective way of accomplishing that is being conservative with your highpass use and orders and sticking to shelves and 1st order filters for the most part if you can get away with it

[fese]

... Use your ears and bypass button!

I find it incredibly hard to operate the bypass button with my ears! I much prefer my hand.

[meloco_go]

... Use your ears and bypass button!

I find it incredibly hard to operate the bypass button with my ears!

Is this an idea for a new kind of controller?