Monday, 6 February 2012

High pass filters

I have to start this blog by saying thanks to all those who read the first article. I was delighted that so many wanted to hear my inane nerdy drivel.

I never explained anything about myself in the first edition and I won’t here either. Just head over to and you’ll see for yourself.

High pass filters

Todays blog is all about high pass filtering. It’s quite a simple concept. Again, like phasing, if you just take a few minutes to pay attention to where it’s needed in your mix then it’ll make a difference.

A high pass filter cuts low frequencies. That is it only lets “High” frequencies “Pass”. It’s a very simple thing but you’ll find just applying it to a handful of tracks will make the low end of your mix much tighter.

On the right is a typical EQ plugin. You can see this is set to High-Pass (HPF) and the frequency that the cut starts from is at 100Hz. You can adjust that number to whatever you want.

So if you’re cutting low frequencies obviously you don’t want to touch kick drum and bass. Unless you’re, you know, dim.

On a typical band mix go straight for the hi-hat. Put an HPF on it and set the frequency high enough so you cut unwanted low stuff but low enough so you aren’t making the hat sound like it’s being hit with a chopstick.

Repeat this for the cymbal tracks and any other tracks that doesn’t need low frequencies, even the snare drum, and you’ll quickly find that your kick drum sounds way more defined. Just be careful you aren’t setting them too high. When in doubt back it off.

You can apply this across lots of tracks: Vocals, guitars, keyboards, synths etc.

Once you have them set, play your mix back at a section where all the instruments are playing, like a chorus. Have a listen to it and then, while it’s playing, turn off all the HPFs. Does it make a difference? It may be small but it all counts to making your mix tighter.

I’ll be back in a few days with another article. Please feel free to email me questions. I’ll be doing a blog later answering questions.

Also if you want to do the course then call Maggie at The Sound Training Centre on 01 6709033.

Thanks for reading,

Andy Knightley

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