Friday, September 17, 2010

EQ for mixing purposes.

Bass and Kick drum.

I started this very blog for two overall reasons. The first reason was to gain as much knowledge as I possibly could about home recording and mixing. I have learned a lot along the way about mic technique, and I have learned a ton about all sorts of “plug in” tools that are out there. This blog has been both a blast and a God send.

The second reason that I started Home Recording Weekly was to simply pass on what I have learned, in order to help others obtain the best possible recordings that they can get. I wish I had a blog just like this one as I started to learn how to record music at home.

Perhaps one of the most important things that I have learned about mixing is that each instrument or sound has its own “frequency space” that it lives in or occupies. You may have seen the charts that detail the frequency ranges on a line and then list the instruments underneath the frequencies that the instruments most often “live in”. Any two sounds, or instruments, that “over lap”, or live in the same frequency, can quickly “add up”. This may cause your speakers to “fart out” each time that these frequencies sound. Perhaps, once again, the most common example is the bass and the kick drum. The bass might sound great by itself, and the kick sounds great all by itself too, but together there is just way too much common frequency level going out to your monitors. A lot of my old recordings suffer from this “farting out” syndrome. But I am learning as I go.

Here is a copy of just one of these charts. Downloading this image will allow you to increase its' size. Look at the over lapping of frequencies, and make a mental note.

A great way to think of an EQ is as simply an amp or an attenuator for frequencies, and not an amp or attenuator for signal levels.

Adding some EQ might seem like an easy way to boost a signals' overall level within a mix, but be warned, it can ruin a good mix too. Adding too much EQ to any one particular Frequency area of an instrument and you might overpower another instrument within the mix. And EQ'ing out too much detail can cause a thin or a weak signal level.

Look out, and listen for any over lapped frequencies in your mix. You can actually hear this happening as one instrument will tend to get lost in the mix, or it will “fall back in the mix”. Plus, things may get muddy sounding in your mix as one instrument enters the song. These over lapping zones require some special attention to detail.

There are two ways to use some EQ while mixing. These two ways are “additive EQ” and “subtractive EQ”. Before I go any further, a spectrum annalizer will show you visually just what is happening within a mix or a soloed signal. Using a spectrum annalizer will help you to see what frequencies are “captured” within a signal, and just how much of a level to that particular frequency area is being heard.

Additive and subtractive EQ......

Additive EQ'ing adds a boost to certain frequency levels within a signal. This type of EQ'ing can bring an instrument more “forward” in a mix. But be careful, too much additive EQ and things can get muddy, or other instruments will “fall back” into the overall mix. A level of discipline is needed in order to not over do it with additive EQ.

Subtractive EQ can help to accomplish two things. First, it can help to remove any unwanted frequencies from within a signal. Secondly, it can lower certain areas of frequency level from within a signal in order to bring another instrument “forward” in the mix. Some most popular “EQ'ing tools” for subtractive EQ'ing are notch filters and hi and low pass filters.

Here is a look at a typical session, as being EQ'd at mixing.

As taken from the Sweetwater “Tech Tips” page

A common trick to getting a full sound between kick and bass while retaining clarity is to boost the lows on the kick (60-80Hz) cut the low mids anywhere from 150Hz to 400Hz (sometimes called the mudrange) and boost the highs at around 3000Hz. This will provide a solid low end, remove some of the mud in the midrange and accentuate the attack of the kick pedal on the drum.

For the bass, we do pretty much the opposite; cut the lows where you boosted them on the kick (60-80Hz) boost the bass at around 120 - 150Hz which will provide a full bass sound (while occupying the frequency space we made by cutting the kick drum in this range), and boost the highs at around 900Hz since bass also provides information in that range as well. In short, we are emphasizing the frequencies that are important to the sound of each, while cutting the frequencies where they can conflict. Try this technique. You'll get a full bottom with a clear thump with a defined attack in the kick and a clear, full bass.

Another important thing to keep in mind is what we said earlier about the most power in the mix coming from the low end; EQ is frequency dependent amplification, which means that we are boosting the power of a particular frequency. Too much boost can result in either distortion or less headroom in the mix for other instruments, so use it sparingly. If you're boosting a frequency in one instrument, you should cut that frequency in another instrument, as our kick and bass technique describes. Overall, EQ is most effective as a subtractive device, not additive.”

Just to shed some light on the importance of the high, mid, and low frequencies within the kick drum, check out this great video......


  1. Thanks for the tips! I'm having a hard time in sound mixing but based from what I read now I can correct my mistakes. I just recently setup my home recording studio in my new apartment.

  2. Glad that I could spark some sonic detail to your work! Thanks for the comment too, nice digs you have!