Hi hat EQ trick

A trick for EQ’ing hi hats

Whether you are using real hi hats or samples, I personally find them the most difficult thing to EQ. Harsh sounding hi hats can make your mixes sound obviously amateur. Here is a trick for making it easier. (This method mostly applies to hi hats recorded on their own, not as part of a drum kit).

This article doesn’t apply to when you have recorded a whole drum kit together – where your overhead mics should pick up a good overall sound, and a gentle high shelf boost would be enough if your drums aren’t bright enough.

But if you are:

  • Using a single hi hat sample
  • Using multisampled hi hat parts from Kontakt, Addictive Drums, Superior Drummer etc
  • Recording live hi hats on their own, separately from the main drum kit
  • Recording a drum kit, but mostly using a close mic on the hi hats, instead of overheads

…then this trick is for you.

The problem

Quite often I find that hi hats aren’t bright enough, but boosting the high (or very high) frequencies with a shelf just makes the hi hats sound too bright, too harsh, or too thin. Taking the opposite approach of simply removing the low frequencies can actually make the hi hats sound less crunchy, and even more thin.

So what’s the solution?

Well, any given hi hat cymbals usually have a particular frequency range which is harsh and needs to be cut out. But because hi hats are very high in pitch, it can take a long time to hear where the harshness is – because high frequency ranges are difficult to discern. But if you can find the “harshness zone” that needs to be cut out, then it becomes much easier to get your hi hats to sit in the mix.

Of course, when mixing, you should always use your ears. And you should always use EQ in the context of a whole mix. But for hi hats, it can be difficult to even know where to start.

Two difficult hi hat examples

Here are two hi hat parts that are a bit problematic. The first is a pair of Zildjian K Constantinople hi hats that were mic’ed up with a Shure SM81 about one foot above, and recorded live:

 

They are lacking in high end, and there’s a little bit of harshness there.

Our second example is a hi hat pattern that I programmed, using a deeply-multisampled hi hat instrument from a well known virtual drum kit plugin:

 

These are very harsh, and lacking in air. This is the kind of annoying hi hat that really needs to be sorted out.

The technique

The first step is to load up a pitch shifting plugin on our hi hats’ channel strip. But don’t panic – we aren’t actually going to pitch shift the hi hats. We are simply inserting a temporary pitch shifting plugin to help us work out where we need to cut, and then we will remove the plugin afterwards.

Now you can use any pitch shifting plugin, as long as it allows you to shift your audio down by 12 semitones, which is the same as half of the pitch or frequency. Good plugins for this include zplane Elastique Pitch, Waves SoundShifter, or Celemony Melodyne in percussion mode. Some DAWs, such as Reaper, have Elastique pitch shifting built in. But whatever plugin you use – it must also meet these two additonal criteria:

  • First, it must be FFT-based, and not based on granular pitch shifting. You can tell if a pitch shifting plugin is FFT based because it will usually have a long latency such as 2048 samples, or double or triple that.
  • Secondly, it must shift the formants by exactly the same amount as the pitch. Usually this is a standard side effect of most FFT based pitch shifters, but some allow you to adjust the pitch and formants separately. They must both be shifted down by 12 semitones, or half of the pitch.

Once you’ve loaded your pitch shifting plugin, you can then load a plugin which has a frequency analyzer. Most standard EQ plugins have an analyzer. If yours doesn’t, the free Voxengo SPAN will help you out. I personally like to use Fabfilter Pro-Q.

Now that we have done our pitch shifting, here is the pitch-shifted spectrum for the live hi hats:

Live_Hihats_shifted_spectrum.png

We can see that a wide cut at around 2.8 kHz would flatten out the pitch-shifted spectrum. But here’s the trick: when we remove the pitch shifting plugin, this will mean that we need to cut at twice that frequency, which is around 5.6 kHz or so.

Here is the pitch-shifted spectrum for the multisampled hi hats:

MS_Hihats_shifted_spectrum.png

First, note that the information at around about 16 kHz must be aliasing from the pitch shifting plugin, because as  I am working with 44.1 kHz recordings, there should be nothing above 11 kHz when shifted down by 12 semitones. So we can ignore that area.

We can see that, to flatten out the pitch-shifted spectrum, we would need to cut at around 3.5 kHz. When remove the pitch shifting plugin, this will mean that we need to cut at around 7 kHz.

The result

Here are the EQ curves I actually applied to the hi hats. However, note that EQ’ing the hi hats on their own, without any other instruments in a mix, is an artificial situation. Also note that I have exaggerated the EQ slightly to make it obvious what has been done. In reality, these would not be the final EQ settings that would be used in a mix – the EQ’ing would have to be done in context.

So here is the EQ for the live hi hats:

Live_Hihats_EQ.jpeg

And this is what they sound like now:

 

And here is the EQ for the multisampled hi hats:

MS_Hihats_EQ.jpeg

And this is what they sound like now:

 

I’ve combined the cuts with a very high frequency shelf. I’ve also cut out some of the low end out of the live hi hats. But for the multisampled hi hats, I felt this was unnecessary. You might be surprised to hear, given the constant “high pass filter everything!!!” advice that often gets carelessly thrown around, that the lower frequencies are actually quite important to the punch and crunchy sound of hi hats.

In conclusion, this isn’t a definitive guide to EQ’ing hi hats – but merely a technique I sometimes use to get started. Remember to always do whatever sounds good!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s