Understanding EQ: Looking at Bass Frequencies

 A common problem faced by new home studio producers is that they don’t realize that unless you have a high quality set of monitors with a capable subwoofer, your speakers probably aren’t showing you all of the bass that is in the mix. And just because you can’t hear a certain frequency, it’s still very much there, waiting to peak out in all of its raw unbalanced glory on a different system capable of producing it, but by getting to know exactly how your monitors sound with pro mixes, you will give yourself the best shot at compensating for all the variables that your system might not be showing you. Alright, so let’s say you have your monitors reasonably figured out and have already recorded that bass track through your preferred method of recording – now you are ready for some EQing! …But you don’t know where to begin... or what to EQ for that matter! Well, there are a few things you should know that can make the task a lot easier.


The High Pass Filter

For those of you who aren’t exactly sure what a high pass filter is or how to use one, it is essentially an electronic filter that is used to reduce the amplitude of frequencies lower than the cutoff frequency point. A lot of speakers and subwoofers have them built in to their system as a way to prevent very low end bass frequencies from causing damage or interfering with the overall performance of the speaker and many DAW programs offer plug-in high pass filters as well. Some of you out there might have heard about this filter by its other names such as a low-cut filter or a bass-cut filter, so you might be asking yourself, if we’re going to use a high pass filter for a bass track, wouldn’t cutting the bass defeat the purpose? Well, not exactly.  

When it comes down to it, creating a good mix essentially requires great balance and great overall tone. While a balanced track is a bit more concrete as far as what it should sound like, great tone is far more ambiguous as it depends on what the producer is going for. Regardless of what tone you’re aiming at, just from my own personal experience I can tell you that most of the time, even if a bass track sounds perfect on its own, it will still need a fair amount of manipulation for it to fit well with the entire mix. This is where the high pass filter comes in. When it comes to low-end frequencies, everything below 100 Hz is mostly heard as a rumble, that is to say it’s the part that we can usually feel instead of hear, and while you most certainly want this rumble in your final mix, using a high pass filter to remove it temporarily will make crafting that bass line and its subtleties much easier, especially when you’re trying to mix it in with the rest of the track.  I suggest using the high pass filter to remove everything below 100 Hz. From there, it will be much easier to use EQ to fine the bass tone you are looking for and once you are satisfied with what you have, you can start bringing back that rumble. Also keep in mind that while sometimes you can go ahead and completely remove the filter, sometimes leaving it in at a certain amount such as 50 or 60 Hz will give you a better overall mix depending on how much bass is present in the genre you’re going after. Alright, so what exactly should you EQ?


What to EQ

In general, most bass guitars will always tend to have a lot of energy between 100 and 500 Hz which is pretty much the low-mid area. To make matters worse, after mixing in vocals, guitars, keyboards, drums, etc., you’re going to have a ton of low-mid boom. All this extra muddle in the low-mids translates to one thing – unpleasant and offensive to our ears! While it might not sound band in a musical sort of sense, too much low-mids tend to create a sort of pressure affect that just doesn’t feel right and if left untouched, it will keep your mix from sounding balanced – hence – professional. Which frequencies you will need to cut down will vary from bass to bass as well as from performance to performance, but you should still be able to find those problem areas by focusing between the 100 and 500 Hz area. You can make things much easier by giving this area a huge decibel boost with the EQ and sweep through the frequencies until you find the areas that sound unpleasant. It’s easier than you might think, but just in case it seems a bit too much too soon, take a look at the two different bass frequencies above.

You should notice that while they are pretty much similar in general shape, they are still slightly different. Even then, both EQ curves show that similar techniques were implemented, especially towards that problem area of the low-mids that we talked about. Take a look at the various different boosts and cuts (shown as dB) applied to both curves. The first big cut you should notice is the -13dB applied at the 240 Hz mark for the curve to the left and -9dB at the 200 Hz mark for the curve to the right. The reason for this was that these two marks had way too much presence and needed to be toned down or else they simply would have over taken the track. If it sounds like it might be a shot in the dark trying to find these areas, it’s really not, just listen and they will be fairly obvious, but again, look for it around the low mids. Next, take a look at the range between 500 Hz and 3 kHz. They are slightly boosted on both – at the 540 Hz mark for the left curve and at the 1 kHz for the right. Both have been boosted about 6dB. This is a common technique applied to bass guitar mixes as boosting this anywhere between the 500 Hz to 3 kHz range will help bring out the finger plucking/picking noise of the bass strings, which in turn helps the bass sound a bit more pronounced during the final mix.


One Last Thing...

While there are certainly several more little tips and techniques that can be applied, the general ideas spoken above is essentially what you are aiming for when it come to EQing anything – applying cuts where things are too muddy and giving it a little boost where needed, kind of like smoothing out a lump of clay into something that actually looks great, or in the case of music, sounds great. One more thing, when it comes to EQ, you should always cut before you boost. Just like blowing up a picture above its native resolution (which makes them fuzzy in case you’ve never done it), removing frequencies will always sound much more natural than boosting them, so just keep that in mind. Remember, every instrument and their frequency ranges have their own set of typical problem areas as well as certain applicable techniques. While this is simply a brief intro into the deeper art that is EQ, it’s not going to get any easier until you try it out for yourself.

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