Equalization (EQ) is the most used effect / modifier in the audio world. While there are no hard and fast rules to using EQ, there are some guidelines that can help you utilize this tool effectively.
Personally, I like to record as flat as possible, that is I tend not to adjust EQ during the recording process. I would feel quite different about the situation if I was recording a live band in a performance situation. Since I would already be EQing each mixer channel so it sounds good live in the given space, I would tend to record the tracks post EQ if possible, in an attempt to document the particular sound of the mix of that given performance.
Another element to consider during the recording process is mic selection and placement. If you make good choices at this stage, you will have less work to do in the mixing stage. I tend to try to use mics that have as close to flat frequency responses as possible, though I tend to use dynamic microphones (that may boost 5kHz a bit) when recording snare, kick, and guitar amplifiers. I would also use dynamic microphones for tight miking most other percussion instruments (cowbell in particular). However, I typically make this choice as much due to SPL levels as I do for getting that 5kHz presence peak.
Most guidelines for mic placement are designed to give you a decent balance of the given instrument’s tonal characteristics. That being said, there are some instruments where there is no consensus on mic placement, and different options may highlight different portions of the instrument’s frequency range. For instance, pointing a microphone towards an acoustic guitar’s sound hole will result in a deeper, bassier tone that can sometimes sound a bit boomy. Pointing the same mic more towards the finger board will give you a more trebly sound (which could sound thin). Angling the mic somewhere between those two positions may get you the general balance you are seeking. If you have the luxury of time during your sound check process (and you should always strive to have that luxury, as it is really more of a necessity), don’t be afraid to spend some time with mic placement with the performer playing at performance volume with that particular track soloed out so that you can hear the tonal quality.
If you want your mixed audio to sound natural, and you have used decent mics, and placed them well, you should have to do only small adjustments to any given track’s EQ. However, don’t be surprised if you use EQ on nearly every track (pre-existing loops in most recording / sequencing software tend not to need any EQ, as they have typically already been equalized). I tend to put EQ as the first item in any effects chain. The only reason you’d really want to put EQ later in the effects chain is if you are using plugins that can drastically alter the timbral balance (Dessers, Multiband Compression, etc.), and want to readjust after the plugin. However, beware that you aren’t simply undoing the adjustment you made.
One common approach is to use the lowest shelf filter of the EQ to attenuate any frequencies below the lowest frequency that can be produced by a given instrument. Likewise, for any bass instrument that has little to no audio content in the high frequency range (10kHz or so), the highest shelf filter, can be used to attenuate any frequency above the highest overtone that is produced by a given instrument. This technique can be used to reduce room noise and leakage.
Another useful guideline is to use EQ to cut unwanted frequencies, rather than to boost desired frequencies. The logic of this guideline is that if you use EQ to boost, you’ll increasingly run the risk of adding distortion. For a beginning audio professional it is easier to hear the desired frequencies rather than to identify unwanted frequency ranges. When your EQ has a master gain setting you can still boost frequencies, but then use the master gain setting to pull all the frequencies down to compensate.
Now when it comes to adjusting EQ settings, you may try one of three approaches. One of these is to try the plugin’s presets. A second approach is to use recommended settings for a given instrument as noted in a book, article, or trusted website (I will put my personal book recommendations in a separate post). The final approach is to try changing the settings on your own. While the first two approaches are completely legitimate, in the long run you will want to become comfortable changing settings on your own, using only your ears as a guide.
Take a recorded track, solo it, and add EQ to the channel. While you are listening to the track boost a single band somewhat dramatically. Sweep through the frequency spectrum while you are listening. Listen for what parts of the sound are in what ranges, and what ranges sound good, or seem to emphasize the characteristic sound of that instrument.
Once you find a frequency band that sounds good, tweak the range by moving it around in a smaller range while listening to the sound. You can then broaden and narrow that bandwidth by using Q or resonance. Once you find what sounds better, a broad bandwidth or a narrow bandwidth, you can move on to amplitude. Move the bandwidth up and down vertically to boost that frequency more or less until you settle in on your desired sound. If you noticed several effective frequency ranges, do this process using one bandwidth for each of the effective ranges.
Notice how much louder the track is with your EQ boost. You may then pull down the EQ’s master gain level a corresponding amount to compensate. Once you think you have the settings you want, toggle between having the EQ on versus bypassed to make sure you like the resulting sound better than the original.
Tackling Reverb
I think of reverb as being kind of like ketchup, namely the right amount is supremely tasty, a bit too much can over power and ruin the flavor. What constitutes that sweet spot is of course personal taste, but finding the right settings to achieve that goal can be daunting, particularly considering the number of parameters in many reverb plugins.
Perhaps the simplest manner is to start with presets. Find something that kind of suits your tastes, and edit the parameters from there. However, if you want to start from scratch, and forge your own sound, some advice might be useful to get you started.
The two most basic settings for reverb are the mix (or wet / dry balance) and reverb time. If you think of a real reverberant space, reverb time is the amount of time it takes for the sound to dissipate (technically for it to drop 60 decibels in volume). The mix (or wet / dry balance) would be the distance from the original sound source. For instance, having the mix near 0% (or dry be loud with wet turned down) would be close to the original sound source. A mix level nearer to 100% (or dry being quiet, with wet turned up) would be far away from the original sound source.
When I start building reverb from scratch, I like to turn up the mix to 100%, so I am listening only to the sound of the reverb. Once I get the sound where I want it, I can dial the mix back until I like the balance of the dry and reverberated sound.
Once I set the mix to 100%, I next set the reverb time to set the size of the virtual space of the reverb. Do I want a small or a cavernous sound, or somewhere in between. To sound realistic (which is not necessarily important), it is best to stick to times under four seconds.
Then I like to play with any setting that would determine the size of the room. Subsequently I like to modify any setting that changes the tone color of the reverb, such as low frequency levels or high cut levels. If you are looking to emulate a natural reverb sound, you want to cut out some of the high frequency components, as that frequency range tends not to reflect off of surfaces very efficiently. Finally, I like to move on to other settings that control aspects like density and diffusion.
Again, once I am satisfied with the overall sound of the reverb, I mix in enough of the dry tone so the original sound has enough presence, and the reverb fades into the background. During the process, you will probably adapt to the sound a bit, so most people tend to use more reverb than is necessary. For this reason, it is advisable to listen to it again the next day when your ears are fresh and dial it back a bit if so desired.
That being said, reverb can be a great tool for hiding thin or poor tone quality (particularly on vocals). It can also be used to mask small mistakes. Overusing reverb in this manner as a crutch can result in you not addressing more fundamental performance, recording, or editing issues that can be fixed with a little extra experience or practice. However, when you find a reverb sound that you like, save it as a preset (using a name that is meaningful to you, or relates to the specific project so you will be able to recall it). Saving your own presets can allow you to build a catalog of your own sound. But remember that a little reverb can go a long way. Avoid slathering it on too much, unless you want something that sounds very effect-y in nature.