Category Archives: Equalization Techniques

High Frequency Management



I recently received numerous questions regarding high frequency management of a mix. Among them, two stood out:

Nicola from Australia asked:

” How do I take out the shrillness of the high voices and flutes without muffling them?”

Fred from France Asked:

“How to know if the mix has too much low frequencies or too high frequencies (and vice versa)?”

High frequency seem to be an issue for a lot of people and I can imagine multiple reasons for that:

  • Overtones from lower frequency harmonic distortion will appear at the top of the spectrum and will make a mix seem brighter than it really is.
  • Affordable speakers are usually not linear in the top end region and have terrible harmonic distortion profile in that region as well.
  • Compressor detectors are more easily triggered by the low end content, so the dynamic of the top end remained uncontrolled.
  • Acoustics has a huge effect on both ends of the spectrum.

Answer to Fred’s question

 “How to know if the mix has too much low frequencies or too high frequencies (and vice versa)?”

The obvious answer to Fred’s question would be “Well, you listen to it…”. The fact that the question remains means his problem is more closely related to his listening environment as he does not seem to trust what he’s hearing. Technically, if you have a perfect speaker in a perfect room, and you listen to the best reference available long enough to print that balance in your mind, every mixes that you will produce will have the right balance and translate well everywhere. Now, we know that there is no such listening environment, but with a decent budget and a lot of work we can approximate it.

In fact, having a dedicated room for mastering is an on-going work. It requires constant work, and the addition of slight improvements will make a huge difference at the end.

Having the right monitors is the first step. That one is relatively easy to take care of;You learn a lot on the subject, consult many people and you can buy something very decent with the money you got. Usually, the hard part is to integrate in the right room. Without writing an article about acoustics, here are some guidelines you can follow to maximize your chances of success:

  • Size your speakers accordingly with your room. If you convert your  small bedroom into a Sound Studio, don’t go with huge speakers with 2x 10″ woofers, the low end will react badly, pretty much like a over sized sub woofer in a car. Bookshelves are good for small rooms, Slim towers for medium room size, and big monkey coffins for big rooms.
  • You should place your speakers away from the walls, especially if they are back ported.
  • You and the speakers should form an equilateral triangle.  The more driver you speaker has, the more distance you will need between you and the speaker for them to sum up. (You will have to be further away from a 3.5 way speaker than from a 2 way.)
  • The closer you are from the speaker, the quieter you’re monitoring to your mixes, less you will hear the room and the more you will hear the details.
  • Compensate for your speakers weaknesses; Wood floors will sound bright, carpet sounds dull, brick sound mid rangy, etc.
  • Some active speakers have tweeter level adjustment. By listening to reference recordings you can tweak it so the speaker blends into your room.

These are the first top recommendation I have on the top of my mind. Please do not hesitate to ask any other questions here if something isn’t clear. Don’t forget, the more critical is your listening environment, more you will be able to trust your ears and go with the flow!

Answer to Nicola’s question

” How do I take out the shrillness of the high voices and flutes without muffling them?”

If well recorded, high voices and flutes shouldn’t sound harsh at all; They are soft and smooth instruments. Adding high frequency to such instrument is usually desired, as it brings out “air” and detail. The first thing we have to figure out whether this shrillness really is in the recording in the first place, or simply if it’s the monitoring that is harsh sounding.

Having heard the original recording in question, I would be tempted to think that its the tweeters of your monitors that are harsh sounding, as the recording sounded very smooth and define. The best way to know is by listening to reference recordings. Are they feeling the same way? If the answer is yes, then it’s coming from the tweeter. Lowering it down might help the problem.

If not, “shrillness” or “harshness” is usually associated with high distortion levels. Make sure you have no distortion/saturators/exciters in the chain.


Still, cheaps audio interface have the nasty tendency to add harshness to a recording.  In that case, the only solution is to spot the worst harsh sounding frequencies in the recording and to notch them out. Sometimes a little 0.5 db notch does all the difference. If that frequency is really hurting, you might need more than a db. Personally, I combine many of such notches on every fatiguing frequency during mastering, so a loud master won’t sound harsh and aggressive.

Or could it be dynamics ?

As mentioned earlier, a compressor will be triggered by lower frequency content. Therefore, it often happens that the low end is pretty tight, but the high frequency content remains uncontrolled. In that case, a DEESSER might be the right solution. A deesser is in fact a high frequency limiter and it definitely is a very powerful tool. This tool was originally invented to take care of agressive “sss” sounds that are often present when recording speech, but it can be used for anything dynamic in the high frequencies. I personally use deessers on about everything that has dynamic high frequency content. It’s mainly useful for cymbals, high hats, vocals, shakers, guitars, and of course, overall mixes.