Hi Everyone
So I just bought a new microphone – an Audix f10 – to be used on Electric Guitar cabs when I’m doing sound. The microphone is small and light, yet well built and solid. It comes with a handy carry case, which is very well padded for protection of the microphone.
I will post a review of it once I use it in a live gig on Sunday evening
Thanks
Audix f10 with protection case
Working backline (Drums, guitar amps and bass amps) at one of South Africa’s biggest festivals.
In the last post, I mentioned these guys “Fletcher” and “Munson” and something called “Equal Loudness Contours”. You may have been wondering what exactly this is, what does it mean and who does it work?
In 1933, two scientists – Harvey Fletcher and Wilden Munson – discovered that the human ear hears different frequencies at different volume levels. With extensive experimentation on many different people, they began to develop a graph showing the threshold of hearing at different frequencies. The “threshold of hearing” is generally considered to be 20 micro pascals of air pressure on the ear-drum. With these tests the graph came out looking something like this:
where the Y-axis is the sound pressure in dB (decibels) and the X-axis is the frequency in Hz (Hertz).
As we can see, the human ear requires much more pressure in the lower frequencies to be heard at the same level as some of the higher frequencies.
You may also notice a word called a “Phon” – this is a measurement of the decibel rating at 1000 Hz or 1 kHz. These are the numbers which define the contours, similar to the contours on a map in a hilly area. We can also see that the contours get flatter as the sound pressure level gets higher.
The way our ears hear certain frequencies is no accident. This has happened over millions of years of human evolution. You will notice that the lowest point in around where humans speak at about 2.5 – 3.5 kHz (surprisingly high hey!).
In the next post, I will talk about Psychoacoustics, which is they way our brain can decipher information coming from our ears and what it can do with it.
Hi guys
Today we’ll be looking into how we as humans hear sound as well as how sound travels, the speed of sound and also touch on the Fletcher Munson Equal Loudness Contours (which I will go more into more depth tomorrow).
So, here is a question: “What is the most important gear that a sound engineer has?”
Take some time to think about it, as there are many possibilities…
Right, most of you would have jumped to things such as “the mixer”, “the microphone”, “the speakers”, “the amp” etc etc etc
Well, you’d all be wrong. THE most important piece of gear that a sound engineer has is his/her ears. Yes, your ears. The little piece of flesh on the side of your head. Without these, your brain would not be able to interpret sound, or give you spacial awareness. The ear may look simple from the outside (“a little piece of flesh on the side of your head” as I said earlier), but inside, it is one of the most complex parts of the body.
Below are two pictures. The first one is of the outside of the ear, while below is a picture of the inside of the ear. See how complex it actually is.
Don’t worry, we will be discussing the inside in detail later on. First though, we must understand how sound travels in order to get to our ear.
Sound travels in waves through any medium that it can vibrate. Mediums such as air, water, concrete etc spring to mind. Any medium that is a solid, a liquid or a gas has the ability to be vibrated. The less of the medium that exists, the less vibrations are going to take place. Also the medium affects the speed at which sound can travel. Solids have particles that are more dense that liquids and gasses so can therefore handle more vibrations. Normally, sound travels through air for us to hear where at 18°C it travels at 342.376 meters per second. This is calculated with a fairly simple calculations:
c = 331.45 + (0.607 x Dc) Where: c = the speed of sound & Dc = the temperature in 18°C.
So the calculation would come out as:
c = 331.45 + (0.607 * 18)
c = 331.45 + 10.926
c = 342.376
Sound is usually measured at 18°C.
Now that we understand how sound moves, we can start to understand how our ears receive the vibrations in the air.
If we go back to the picture of the ear:
We can see here that vibrations come into the auditory canal in the form of vibrations. These vibrations vibrate the ear drum which is a skin membrane stretched across the end of the auditory canal. This in turn moves 3 bones (the smallest in the human body) the Hammer, the Anvil and finally the Stirrup. The stirrup will vibrate another membrane, behind which is the cochlea. The cochlea is filled with a liquid which will cause waves, similar to dropping a stone in a pond. Lining the cochlea are over 30,000 microscopic hairs, whose ends connect to nerves which go to the brain. These hairs each pick up a different frequencies, and amongst them, they make up the frequency range which we hear. So our ears are fairly similar to a microphone – The air vibrates a membrane which sends an electronic signal.
I was going to touch on the Fletcher Munson Equal Loudness Contours today, but I think I will leave that for tomorrow.
Hey there.
So as I said on the about page, this blog is really for anybody who is interested, involved in or just wants to learn more about sound and mixing it. To start of with, let me tell you a bit about myself.
I am currently 19 years old, living in Cape Town, South Africa where I study at Cape Audio College. I’ve been doing sound since I was 12 years old at school and took to it and now have made a career out of it. I currently work freelance for various companies in Cape Town and do mostly live sound work.
If you have any questions don’t hesitate to contact me through themixengineer
Tomorrow I’ll start off with some fundamentals of how sound works.
See you then
