Steve Metcalf has been a part of our Gibson’s team since March 2005. With a background in professional audio and a passion for home entertainment, Steve is able to explain the features and benefits of today’s technology in a way that is meaningful to you.
All About Audio:
The science of Music and Film Audio from Performance to Playback.
I was asked to blog a little about audio in order to try and shed some light on the many considerations involved in selecting good quality audio components for your home theatre or two channel audio system. The objective of this is to give readers the tools they will need to make informed decisions about the various audio products that will ultimately comprise the “dream system” that all music and film lovers are seeking.
In order to do this, I feel it is necessary to go through the basic concepts of sound recording and reproduction. Once we understand the way that sound is captured, processed and delivered to your home, you will then be able to assess the performance of your system and seek out specific products to improve that performance.
There is much to talk about, so over the next several posts I will try to explain these things one step at a time. I will take you on a little tour of a music recording, starting with the performer and his/her musical instruments – all the way through to the speakers in your room as you listen to the final product on Vinyl, CD, DVD, SACD or Blu-ray disc.
What is Sound?
The first topic to discuss is the sound itself. In real life, when someone plucks a string on a guitar or claps their hands, what is acutally happening to make this sound? A soundwave is really just a series of changes in air pressure. In the instance of a hand clap, your hand would quickly squeeze the air in between your hands. This would cause air pressure to go up. The pressure would rise both between your hands and around them where the air is displaced. Eventually the air would come back to rest as it was before the hand clap, but a few things happen in the meanwhile.
If you have ever whipped your garden hose to relieve a snag, you would notice that the whip travels along the hose, but the hose comes to rest with one end still in yourhand, effectively the hose hasn’t moved (side to side movement doesn’t count in this example! 🙂 ) The pressure from the handclap travels through the air in much the same way as the whip in the hose. First a rise in pressure, then it falls to where it started. As the wave travels through the air, the air pressure will drop below where it started and then come back again to zero. This can happen several thousand times per second, for several seconds. Positive pressure, zero pressure, negative pressure and back again, travelling away from the source at over 1000 feet per second. When this sound reaches your ears it causes your eardrum to move in and out in direct relation to the pressure of the air. This is of course how we hear sounds.
The microphones we use to capture sounds are effectively an electric eardrum. The sound pressure moves a thin sheet called a diaphragm. This is similar to the eardrum. When air pressure causes the diaphragm to move in and out, it causes the microphone to produce electricity. The amount of electricity goes up and down with the changes in air pressure and then this electrical information is usually recorded to tape or hard disk.
In the end, (after many steps in between) this electrical information is used to move your speakers in and out, which in turn creates the sound that you hear. The next few posts are going to look at this process in greater detail. We will talk about how the captured sound is recorded and mixed in stereo for your LP records, CD’s or other listening source. As we go through this process step by step, we will learn about the challenges that exist when trying to produce a lifelike rendition of your favorite performances in your home.
If you have any questions, please don’t hesitate to stop by the store and chat with me. You can always email me at firstname.lastname@example.org or follow me on Twitter @SteveMGSV . Make sure to follow us on Twitter and Facebook to keep up-to-date with all of our blogs!