Sound Recording - the WellMixed.com Blog

The blog has not been well-tended recently, but now it will be even less so, as the WellMixedStore.com takes over the NavBar link on the main website.

However, this means the beginning of a new era, where the microphones that you want to listen to are available at WellMixedStore.com

News about all thing related to home recording will be more constantly posted on a little microblogging platform that you may have heard about called Twitter. Be sure to Follow @WellMixed there.

Tinnitus, or ringing in the ears, is one of those medical mysteries whose cause is unknown to medical science. A common thread is loud noise, whether it be a single exposure to a jack hammer or constant traffic noise as one drives with the window down.

However it is caused, the resultant ringing is particularly troubling to musicians as it interferes with the enjoyment of music. Check out this CNN-produced video featuring Dr. Sanjay Gupta and Lars Ulrich.

Have you ever experienced a ringing in your ears? Leave a comment below and tell us about it.

You may have seen 44.1 KHz on CD packaging. This number indicates that the audio on the CD is composed of 44,100 “samples” every second.

What are these samples of?

They are samples of loudness. (Click here to read about loudness and bit-depth.)

So this means ——> There are 44,100 different loudness levels stored on every second of CD audio.

AND (theoretically) —–> The speaker in your car, home stereo, or headphones moves between 44,100 distinct spots every second.

So, in digital recording, we want to have a lot of samples every second; at least as many as are going to be played back for CD quality audio.

During recording, computers take “samples” to determine how a microphone’s diaphragm is being moved by air. (This trading of information is known as transduction.)

When a loud noise pushes air against a microphone’s diaphragm, that diaphragm is moved far from its resting place. If the diaphragm position is sampled when it is far from its neutral resting place, the computer will record a large number.

If the diaphragm position is sampled when it is at rest, the computer will record a zero.

There are, of course, many numbers in between.

Since the introduction of the CD in the early 1980’s, we have been listening to 44,100 unique volume levels every second whenever we play our favorite music. With DVD Audio, SACD, or digital download, we may begin to hear 48,000  or  96,000  samples per second.

41,000 samples per second, however, are more than adequate for reproducing all frequencies that human beings are capable of hearing.

The process of recording is completely reliant the process of transduction. So what is that?

Merriam-Webster [on-line] says that “to Transduce” is:

to convert (as energy or a message) into another form <essentially sense organs transduce physical energy into a nervous signal>

There are many transduction that occur in the recording process. The modern recording signal chain often goes like this:

Mechanical movement (a moving guitar string)

to

Waves (pressure differences) in air

to

Mechanical movement (a moving microphone diaphragm)

to

Electrical signals in a wire (magnet, ribbon, or condenser to mic cable)

to

Numbers on your hard drive (A/D converter)

It’s amazing to think that all of these forms are essentially the same information, yet the media is completely different in each case!

What does it mean when your audio is 16-bit or 24-bit?

It’s all about how descriptive the audio is with regards to loudness.

The diagrams below represent a waveform sampled and recorded by a 16-bit system, and then a 24-bit system.

The X-axis represents time. You’ll notice that the samples are taken at equal point in time on both systems. (Each line vertical line might represent 1/48,000 of a second.)

The Y-axis represents loudness. You’ll notice that the maximum and minimum loudness on both systems is the same. However, you’ll notice that there are more horizontal lines on the 24-bit system. This means that there are more loudness samples to choose from.

A waveform read and recorded in 16- bit

The same waveform read and recorded in 24-bit

Digital audio is composed of tens of thousands of loudness samples each second. Specifically, there are usually either 48,000 or 44,100 loudness samples each second.

More after the break….

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