hi, im watching a groove 3 video mixing in cubase 13.
in it the guy is eqing synth sounds
sometimes he uses low cut sometime shelf.
in one instance he says "im just gonna use a simple high shelf to cut out any of the low end" (studio eq)
why not just use the low cut?
thanks.

 

To prevent a drastic phase rotation. Highpassing can often increase crest factor, causing you to lose more headroom than you would by cutting those low frequencies.

I also suppose you were referring to a low shelf, not a high one

 

thanks for reply,i thought he should have said low shelf,but he actually said high shelf.

 

so how are u meant to know whether to low cut or low shelf?

 

Maybe you can elaborate some more on the phase issue. Say you want to remove all the information below a certain frequency. 25hz, 30hz, whatever that number may be.

 

I want to preserve the overall character of the low end, but there's too much of it -> shelf
I don't want to affect my low frequencies' phase -> shelf
I don't hear anything in the low end I care about and I don't care about phase at this point -> cut

But:
- You'd need to flip phase 10+ times before you start hearing a tonal difference.
- It's almost impossible to predict whether a change in phase will net you a tiny bit more headroom or not on the master.

Use whatever sounds best to you during mixing. Give more thought to phase on your master, where you should consider linear phase, for reasons of predictability.

 

Last edited: Jul 5, 2024

Having not seen the video, it is difficult to say what the presenter was referring to exactly. I have witnessed many top mixers say low-pass when they meant high-pass. Often correcting themselves. Video courses can give you info that helps you improve or, lead to to more confusion.

Be careful of those saying that "this is on only way" to do something. Saturation as an example, can be used in place of EQ to tame high end or emphasize low end. Sometimes it can make it worse. All depends on what's happening in the source. This is where tools like Soothe 2 can help.

A Pulteq style may be all that is needed in some situations. Simple low/high boost while giving you cut at adjacent frequencies.

Just use your ears when trying to tame or adjust sounds to make them fit/work with other sounds in a mix.

 

Last edited: Jul 5, 2024

Er, typo?

Nope, if there's a phase interference between two kicks or kick and overheads/room, you'll recognize this pretty quickly. If it's getting worse, the low end becomes less defined, if you improve the phase by adding a low cut (which is very well possible) it gets tighter, more defined and louder.
BTW, allpass filters are very usefull for this, they alter the phase but not the gain.

Which comes with pre-ringing and is very unwanted for the lowend.

 

Funnily, you can achieve very similar results with both, be it high or low. Shelves come with lesser phase rotation even if you pull them up or down by more than 12dB, but they still affect the phase. Normally this isn't as big a problem as it can be with lowcuts.
Keep in mind every EQ is caused by phase rotation (for linear EQs the phase is corrected afterwards, hence their delay).

Rule of thumb, if you don't hear any degradation in the low end, a cut's ok, if you do, it's not.

 

Last edited: Jul 6, 2024

Yes, sorry!

I meant for a single track.

Can you tell by looking at your EQ? Did you improve your low end or did the phase change also make your limiter's life a tiny bit harder without you knowing or even noticing?

That's why I say: '(impact caused by phase change) is almost impossible to predict, use whatever sounds best and consider FIR on the master'.

Depends on how many filter taps you have. I don't think anyone's going to notice ringing from a single 19 tap FIR on the master.

 

Single track? Phase only matters soundwise in interaction with another phase, not on its own.

Let me guess, no one can? ;-)

Yes, like you can with an allpass filter. Why shouldn't this work with a cut?

No limiter applied when mixing.

Absolutely.

Isn't a parameter I've ever seen in an EQ.

 

Loop a kick, put an allpass on 250 hz, copy paste your EQ/allpass 25 times. Your kick now sounds like a rubber band.

Here's a (low cut IIR) filter from Tokyo Dawn Records (written in Reaper JSFX) that exploits this property for 'bigger / longer low end' purposes: https://vk.com/wall-216579052_253 (Tokyo Dawn Records / Labs)

(jsfx is attached at the end of the post)

Because taps are calculated behind-the-scenes, the same way you don't get to input the maximum phase shift for IIR filters in your EQ. (That'd be a very cool idea though.)

 

The basic difference is that a high shelf affects all "high" frequencies equally, or nearly so, whereas a high cut (low pass) filter reduces the level more and more as the frequency increases. So a shelf is more of a high/low balancer, while a filter does what it says: it filters out unwanted frequencies. It's more drastic than a shelf.

In both cases, unwanted resonances can be heard if the internal Q-factors are too high. As always, the best judge is your ears.

 

The problem is not about only phase in the low end. The problem is that phase rotation increases peak factor (and the transient is in an higher part of the spectrum). If you use a linear phase hipass you'll notice the crest factor will remain about the same. A good rule of thumb is to always clip after lowcut and not before, otherwise you'll "waste" the clipping. Panorama Mixing demonstrated it well in a video, but I couldn't find it