TOO DENSE?

You know  when you're working on a mix that has a lot of tracks and you start to notice that the lower midrange and Bass are blurry and indistinct?  That the mix feels cluttered, muddy... even claustrophobic? You're suffering from an obvious malady: the mix is TOO DENSE.

So, in the service of the obvious, a few basic facts:

You probably already know that microphones are divided into several basic types:

• Dynamic

• Condenser

• Ribbon

• Pressure Zone (PZM)

In small project studios and in live sound applications, you primarily deal with dynamic microphones and condenser microphones.  (We’ll talk about the others later.)

Dynamic microphones are rugged, moderately priced workhorse mics that are great for live and studio applications. They are good for recording loud instruments like guitar amps, drums and vocals because they have a tight, punchy, compressed character that emphasizes the midrange.

High sound pressure situations require more detail than a Dynamic Microphone can provide, so we use:

Condenser microphones, which have two basic variations:

• Small Diaphragm Condensers

• Large Diaphragm Condensers

Small Diaphragm Condensers are equally as rugged as Dynamic Microphones but generally get treated a lot better because they are more expensive.  Certain types make great vocal microphones and others shine in matched pairs over a drum kit. They also make great room mics.

Large Diaphragm Condensers are great for detailed vocal performances,  acoustic guitar, acoustic piano, string sections and picking up subtle room acoustics.  They tend to be a bit more delicate and lots more expensive than Dynamic Microphones.

Both types of condensers tend to have an open airy character that represents the entire frequency spectrum more evenly than Dynamic Microphones.

Microphones have three specific pickup patterns:

• Omni-directional (360 degree pickup pattern)
• Bi-directional (figure 8 pickup pattern)
  
• Cardioid (uni-directional pickup pattern)

Cardioid Microphones have a heart-shaped directional pickup pattern.

Dynamic microphones are almost always cardioid– that is, they only pick up sound from the front of the mic.  That’s one reason they are so popular in live sound applications – they don’t feed back as easily as an omni directionals and they are good at isolating the instruments.
Condenser microphones often have a switch on the side that allows you to choose between the three different pickup patterns.

Any cardioid microphone will pick up more bass frequencies if it is placed closer to the sound source. This is called the proximity effect.

The proximity effect is a mixed blessing.

Say you have a wimpy-sounding singer... whiny and ineffectual, tinny, annoying... you can use the proximity effect of a Cardioid microphone to make him sound a bit more beefy and important. Put the mic closer to his mouth and watch the magic happen!

If you are so delighted that you use the proximity effect on everything, close mikng the drums, the guitar, the bass, the keyboards... you'll find that your mix is crowded with lower midrange and bass! It sounds like sludge! Crappy sludge!

If you close mic too many elements and try to mix them together, it will sound  like crappy sludge.
And the more tracks you add, the worse it gets.

How to avoid this:
You can use the proximity effect to your advantage. It just takes a bit of planning.

Drums usually stand to benefit the most from close-miking. Position the mics to get the best sound possible. Don't worry about compression, eq and gating yet... that can wait until you're mixing.  A well-tuned and well-miked drum kit is the best place to start.

Guitar Amps - you'll need to think about how many tracks you are plan to stack and how the tracks are going to fit together.  When you play multiple guitar tracks to thicken up a sound, often one track emphasizes a "beefy low end" while a second track has more of a midrange punch... and a third might be added for clarity and differentiation in the mix. 

In this instance, position the mic on the first track to utilize the proximity effect to its full potential. On the other two tracks you'll need to move the microphone toward the center of the speaker. This will reduce the low end coming from the edge of the speaker, especially if you angle the mic toward the center.  You can also move the mic farther away from the amp if you have a suitable room and suitable isolation to do so. Or you can go direct.

Jimmy Page from Led Zeppelin had a recording axiom that I’ve always remembered:
DISTANCE EQUALS DEPTH (swigs Jack Daniel's and makes a "horns up" gesture)

What he meant is that by miking a guitar amp or drums at a distance, the resulting sound is BIGGER.  The only problem with doing this is that sometimes the room that you are recording in sounds like crap* or you need to close-mic the instruments to avoid bleed from other amps.
*See Flutter Echo in the “NOT” section of this blog

Many mics also have a bass roll-off switch.  People often get confused about when to use it.  The proximity effect can be lessened with a bass roll-off switch if you close-mic something with a dynamic or a condenser microphone set to a cardioid pickup pattern. The roll-off cuts the bass frequencies at the mic.

Vocals – because people tend to record vocals with condenser microphones in a (hopefully) dry isolated environment,  proximity effect is not as much of a concern.  Most condenser microphones have a bass roll off switch that you can use if you decide that the low end of the vocal tracks is a little too beefy, but in general (because you want the vocals to be at the forefront of the mix) it’s better to leave the full frequency spectrum intact and then cut key areas of E.Q. on some of your supporting instruments if you find that they interfere with the vocals.

If You Are Mixing and your sounds are getting muddy in the lower frequencies, cut them out with a parametric equalizer centered at around 200 Hz with a medium wide Q.  You can also use a shelving equalizer to cut out all the frequencies below about 80 or 100 Hz.  This will keep the important midrange and upper midrange frequencies intact, but free up the bass and lower midrange frequencies for the kick drum, the bass guitar, and the lower frequencies of the vocals that make the singer sound so much like Eddie Vedder.

SO:

Close miking with directional (cardioid) microphones makes the low end more pronounced due to the proximity effect.

When you stack tracks that utilize the proximity effect, the low end builds up in your mix and makes it sound muddy

To Prevent This This During Recording

• Preplan your tracks.

• Utilize the proximity effect only when tracks need to sound beefier.

• Minimize the proximity effect on other tracks by positioning and aiming the microphones in such a way that they does not pick up as much of the bass signal.

• Use the bass roll-off on the microphone if it has one.

To fix it in the mix:

• Sacrifice the areas of the some of the low end and low midrange frequencies in your supporting instruments using a parametric EQ with a moderately wide Q (usually the frequency range is 100 – 300 Hz.)

• Use a low end shelving EQ to cut all the frequencies below 100 Hz on your supporting instruments.

Example of Cuts Using  a Shelving E.Q. Below 100 Hz and Moderate Q Centered on 250 Hz

These types of frequency cuts will not be noticeable in your final mixdown because the kick drum, bass and vocals will have low frequencies that will fill up these areas.  The end result is a mix that is clear and uncluttered, yet rich and deep.