A while ago we asked you readers about what kinds of tutorials you
would like to see next. While I went over the very informative list I
stopped at a reader's suggestion. This reader kindly told us that we
haven't been focusing on the most natural thing we audio enthusiasts
use. Namely, our ears. Our ears are the most important aspect of our
music production, without them there wouldn't be much music would
there? Music to our ears would be a mute point, no pun intended...
Now there are a few aspects we should keep in mind when we're
listening to, recording or mixing music. You should be aware of
acceptable monitor levels and the amount of time you should dedicate
to mix work. Our spectrum of hearing also changes over time and there
are certain things you need to be aware of when trying for that ultra
high end sheen. The sad truth is that some people suffer from hearing
related illnesses that can ruin your career unless you take good care
of your ears.
Acceptable Monitor Levels
You should be aware of the volume of the music you are mixing. The
louder you listen to your mixes, the easier your ears get tired.
After mixing for a few hours at an ultra high level your ears don't
respond as well to frequency nuances and you won't be able to make
the correct judgement calls your mixes need.
Volume is measured in dBSPL which stands for Decibel Sound
Pressure Level, or rather the level of sound pressure measured in
decibels. Our threshold of hearing starts at 0 dBSPL and goes up to
140 dBSPL which is a level so loud that it destroys your hearing. The
threshold of pain is at the 120dBSPL level.
This graph can give you a pretty good idea of the typical sound
pressure levels in decibels. We can see how everything below 40 dBSPL is
considered to be very quiet. Anything below 20dBSPL is considered
studio acceptable, meaning that a control room that has a so called
Noise Rating of 20 means that the decibel level of the control room
with everything turned on is below 20 decibels. Decibel calculations
are not lineal. By that I mean that the jump between 20dB and 40dB is
not double the volume. Instead it is almost 4 times louder!
Now, in order to get a good bearing on how loud you listen to your
mixes you will have to buy a decibel meter and physically measure the
noise level yourself. But you can get away with the graph above and
others like it to get a pretty good idea of the volume of your mixes.
In context of correct and acceptable monitoring levels it's a good
starting point to start at 90dB. This is quite loud but it is
generally accepted that you can work up to 8 hours at that volume. 90
dBSPL is also where your ears hear all frequencies in the most
balanced manner, according to the Fletcher Munson Curve.
and Munson curve
As you you can see by the Fletcher and Munson curve your ears need
more level in order to perceive the lower frequencies at the same
level as the others. Our ears are designed in such a way that we are
most sensitive to the frequency area where speech is located. So the
area around 1 Khz, where we most easily hear human speech is most
sensitive and less susceptible to volume changes, as we can still
hear that frequency area at a very low level.
So, if we say that we can monitor best frequency wise, and for a
solid 8 hours at 90dBSPL, how long can we monitor at 93dBSPL?
4 hours? Half the time, but only 3 dBs more?
Yes, because 3 dBs more are twice the power, we can only
comfortably monitor for half the amount of time. And so, step by
step, with every 3 dB we cut our time in half. We
love graphs, so here's a graph:
Amount of time mixing
approx. 4 minutes
Only 30 seconds!
You see how sensitive our hears become
as the sound around us becomes louder? They can't handle that much
noise for such a long period of time, that's why we get ringing in
our ears after loud concert nights, really busy bars and very long
mixing sessions. Your ears get tired and are trying to tell you to
take a break. There's no use in trying to mix after such a long
exposure to loudness anyway. Your frequency judgement gets screwed up
Spectrum of Hearing
It is usually said that the human hearing ranges from 20 Hz to 20
Khz. The sad truth is that as we get older that high end we got when
we were children and teenagers is lost on us as grownups. We tend to
lose around 2 Khz every ten years. Here's another graph to explain:
20 Hz – 18 Khz
20 Hz – 16 Khz
20 Hz – 14 Khz
20 Hz – 12 Khz
20 Hz – 10 Khz
20 Hz – 8 Khz
20 Hz – 6 Khz
I took a frequency test a while ago and
I could only hear frequencies up to around 17.7 Khz. Which, as a 24
year old is pretty good I think. Of course, the graph is not a
definite indicator of the frequencies you can and cannot hear at a
certain age. Obviously it varies from person to person. I know
individuals that are in their early twenties and they can't even hear
up to 15 Khz, and there are probably engineers in their thirties that
can still hear that ultra high end. But this tells us one thing; our
hearing will get worse as we age, but we should try to do everything
in our power, as musicians, producers and engineers to try to slow
down that degeneration as much as possible.
Like I said before, listen to your
music at moderate levels, and not only when you are working on it,
but also when you are listening to your enjoyment. Use earplugs in
high noise situations, such as concerts and any type of situation
where you think your hearing might be compromised. When working as a
live sound engineer I used to take ear plugs with me to concerts.
After I had set the correct levels of the band and had everybody
sounding good I put on my earplugs in order to protect my hearing. I
would occasionally take them out to see if everything was running
smoothly, but working with headphones didn't tire my ears as much. I
mixed better because my ears were always at full alert, not exhausted
after long noise exposure.
Wrapping things up, I think I made my point very clear. Our ears
are our most valuable asset. It doesn't matter if we have the
greatest sounding pre-amps in the world, the warmest microphones or
the clearest monitors. If we don't hear the quality, it won't matter
at all. Take care of your ears, monitor correctly, take breaks from
mixing and use ear protection when necessary. It will result in a
longer and more successful career if you have ears you can trust.
One last note: If you have any special stories, good or bad,
regarding the topics I touched upon please feel free to let us know
in the comments. As audio enthusiasts, we'd like to hear how you plan
on protecting your ears.