Mix Preparation

After all goals are set, organization is the key to staying efficient and motivated. The first step is to design your mix environment. Whether you are using a console or a DAW, the procedure is the same.

Order and label all of the tracks in a coherent manner. For example, you may want to start with drums, then bass, guitars, other supporting tracks, and then finally vocals. You will quickly discover that abbreviations are the key to identifying tracks on the fly.

Patch or route any FX processors that you may want to use in the session. It can really put a damper on your creativity to have to patch in an effect every time you want one. Get as much of the technical chores out of the way as possible, so you’ll be able to maintain momentum.

Apply initial EQ and compression for all the tracks. For now, just worry about corrective processing rather than the final sound. In other words, use the EQ to get tracks to sound the way that they were intended to sound, and use compression to gain dynamic consistency and not necessarily as a noticeable effect.

Noise Gate

OK, I use a gate for a lot of different purposes, and I don’t really think much about it… However, I was talking to a student at BADASS (Boston Area Definitive Audio Student Summit) and realized I might need to go over the basic function of the gate before going into any advance uses…

The main function of a gate (also known as a noise gate or an expander) is to disburden of unwanted noise or bleed. It functions similar to a compressor, where it attenuates a signal. Unlike a compressor that starts attenuating when the signal reaches the threshold, a gate starts attenuating when the signal drops below the threshold. You can also think of it like this: a gate will not open until the signal reaches the threshold.

When removing unwanted noise from a signal it is important to understand that the gate will only remove the noise when the signal is not playing, and will not remove the noise when the signal is present. Although, when the signal is present, the noise will be masked and it is less likely to be heard.

Attack: This setting allows the user to set the desired time it takes for the gate to open after the signal exceeds the threshold.

Release: This setting allows the user to set the desired time that it takes the gate to close once the signal drops below the set threshold. This can be set in such a way that the gate closes slowly, which in turn sounds more natural.

Ratio: This setting allows the user to set the desired amount of bleed, even though the gate is closed. This allows for a more natural sound.

Hold: This setting allows the user to set the time between the release threshold being traversed and the gate being closed.

My New Mic Stand

OK, so I bought a new mic stand… You think that would be the end of the story, but no…

I’ve been working with a great young band in the studio, and last weekend the singer thought it would be more intimate to come by the house to sing. Great. While setting-up the studio, I remembered that my mic stand, lets call it Fred, is broken. I decide that this would be a good time to find a permanent replacement for Fred. No more tape, string, or glue. Fred is to be replaced… Sorry Fred.

So, I go to the local music store, knowing that the artist is almost to the house. This doesn’t leave me much time to look around, but I find the mic stands in the corner of what looks like a perfectly good, yet old, store. There are a couple of good looking boom stands to choose from. Now Fred is a tri-pod based stand with a boom, which is what I was looking to replace him with. Still, I let the sales person influence my decision. He thought I should get the fixed base stand with a boom, that we can call Bob. Bob was marked at half the cost, so I thought why not. Now, Bob and I get up to the register, the clerk that didn’t understand the concept of speed, asked for double the amount… not half. So, me being the Bostonian that I am said… I don’t think so… OK, I’m sure that I used more colorful language… I pointed out the price tag that hung from Bob, that clearly stated half. He then proceeded to tell me that that was the price for the base of the stand, not the whole stand. If I wanted all of Bob, I would have to pay for all of his parts. While processing the stupidity of this conversation, I remembered that I was running late… So, I just paid for Bob and left.

Back to setting-up the studio… I break out Bob and place Steve (the mic) on Bob’s, accessory, boom. Two hours later, we start the session. Things are going great… The artist is happy and we are getting some great tracks. At this point, I’ve all but forgotten about my ridiculous experience earlier. This is when Bob decided he no longer had the strength to hold Steve. Bob fell, and through Steve through the wall. Steve suffered a minor concussion, but was able to get through the rest of the session… The artist on the other hand… She finished the session perched on a freshly dropped stack of bricks.

The next day, I had to send my assistant back to the store, in order to keep me from killing slow clerk, to exchange Bob for Chuck the tri-pod stand. Chuck and I have been working together for about a week now and things seem to be going great. Although I still miss Fred, I look forward to working with Chuck.

Equalizing Reverb

I was mixing a song today, when I was asked by the artist… “What reverb plug-in do you use? It sounds so clear.” I was using the Waves Renaissance Reverb at the time. The client then said… “I have that one and it doesn’t sound like that on my system.” So, today I thought I would talk about equalizing reverb…

Even if reverb settings are adjusted correctly, the effect can still make a mix sound muddy. This is because a typical digital reverb processor applies reverberation to all frequencies. In reality, a room with any absorption in it (people, furniture, treatments) or windows and doorways would not reflect certain frequencies as much.

To compensate for this, apply an EQ processor to the reverb return. Some plug-ins already feature an EQ built in, as do higher-end rack processors. If you find that your mix sounds muddy with the reverb in place, you can eliminate some of the lows to clean it up. Likewise, if your reverb is getting lost without being exceptionally high in level, you can add higher frequencies to allow it to punch through.

Equal Loudness Contours

After thinking about the last post, I have decided to go into a little more detail. Today I will talk about the Equal Loudness Contours, other wise know as the Fletcher Munson Curves.

In 1933, two British scientists by the names of Harvey Fletcher and W. A. Munson researched the frequency response of the human ear with regard to loudness.  As it turns out, the curve is far from flat, and changes in response to SPL.  They found that human beings are quite adept at hearing between 2 kHz and 6 kHz at very low volumes (0-20 dB), but are much less sensitive to low frequencies at that level.  As the source gets louder however, the frequency response generally gets flatter and bass more easily detected.

What does this mean to mix engineers?  It means that if you are to make spectral decisions at too low a volume, you could be compensating for the deficiencies of the ear at low SPLs. When good bass response at low levels is achieved, it is likely to sound too heavy in the low end at higher SPLs.  This is due to your ear’s sensitivity to low frequencies.

This is not to say that you should mix at blistering SPLs, but when making important decisions about the low end of a mix, just know that it is not just your monitors and your room coloring the sound, but your very own ears as well.  You also have to juggle between having a flat frequency response and not subjecting yourself to ear fatigue.

The recommended critical listening level for mixing is 90 dB SPL.  At this level, a relatively flat frequency response can be used with the least amount of risk for hearing fatigue/damage. It has been found that listening at this level is feasible for up to 8 hours without hearing fatigue/damage.  However, for every 3 dB past 90, that time is halved.  If you listen at 93 dB SPL for longer than 4 hours, you are risking permanent hearing loss.  Listening for longer than 2 hours at 96 dB, and you have the identical problem.

An application of the findings of Fletcher and Munson is only as far as a consumer stereo.  You may have seen a control on said stereo called loudness.  What this attempts to do is atone for the deficiencies of the ear at low volumes by placing an EQ on the signal for compensation.  If one were to have the stereo turned up to a high level with the loudness feature engaged, it would be prone to sound bass heavy from over compensation.

Another application can be established on a sound pressure meter.  These devices have a setting that determines how it compensates for the equal loudness curves, called weighting. A-weighting and C-weighting are common, and both roll off frequencies to better estimate what an SPL is relative to the ear.  The difference is in the cutoff frequencies and rate of the roll offs (both require a low pass filter at 20 kHz so ultrasonic sounds do not affect the test results).  One could easily argue that this approach is only accurate at low SPLs because human ears do not roll off lows as much at higher SPLs.  Nonetheless, it remains the convention for loudness measurement to weight the signal.

Fletcher Munson Curves

Monitoring Levels

Today, I was asked why I mix at lower levels.  I guess that’s just what feels comfortable to me.  I do crank things up at times, but overall I do tend to mix at lower levels.

Although 90 dB SPL is considered the best level for monitoring with regard to frequency response, sometimes it is useful to listen at lower levels and occasionally higher ones as well.  At lower levels it becomes easier to hear some of the subtleties of a mix, and this becomes useful for tasks like automating.  A mix may sound fine at 90 dB SPL, but at 70 dB, an element may stick out above the others and become distracting.  You may try listening at 96 dB SPL for a few moments to hear if the low frequencies become overwhelming, and find the medium.

A constructive method for finding the prominent elements of a mix is to lower the monitoring level to a barely audible point. In a pop mix for example, the vocal and perhaps the snare should be the only things heard.  If you were to try this with a mix and the high hat was the first thing heard, you may reconsider the level of said high hat and/or the vocal.

Note: For every 3 dB increase in level, you cut your safe listening time in half. For example; if you monitor at 90 dB you can safely listen for 8 hrs. However, if you monitor at 93 dB you can safely listen for 4 hrs.

• 90 dB = 8 hrs. of safe listening time
• 93 dB = 4 hrs. of safe listening time
• 96 dB = 2 hrs. of safe listening time
• 99 dB = 1 hrs. of safe listening time

Trust me 3 dB is not that big of a difference, so be careful.  If you really want to put things in check, get your hands on an SPL Meter and check the normal level of your car stereo.

Pro Tools – Window Configuration

I’m sure by now that most Pro Tools users are aware of the Window Configuration feature that was released in version 7.3, however some of you may not be aware that you can add a new configuration with the quick key (. + number 1-99 + “+”).  Once you have created a new configuration, you can then access it with the quick key (. + number + *).

I use this feature in every session and these quick keys have really made things easier, as well as quicker.