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Mar 01

MP3 audio and how settings affect your audio recordings

mp3Do you have a digital audio recorder? Are you looking to capture electronic voice phenomena? Before you do you, let’s sit down and discuss how a digital audio recorder works and some basics about the MP3 format and generic recorder settings:

Bit Rate:
How many kilobits the file uses per second. With low bit rates, there are compression artifacts such as ringing or pre-echo are usually heard. This is particularly noticeable when a recording has lots of random changes. 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160 (Supurovic) being the most common. I often describe lower bit-rates as being more “tinny”. For a good example, listen to white, pink and brown noise uncompressed and then compressed to 8-bit sound here: http://noisey.vice.com/…/yntht-there-are-ghosts-in-your-mp3s

Sampling Frequencies:
Due to the Nyquist/Shannon Theorem, a rate of 2x your hearing range is ideal. (44khz for most humans). This bitrate is the most common as it is tied to CD Audio conversions. Think of sampling frequency as having more “slices” of sound allowing it have a more rounded sound. For those math people, digital audio is a square wave but we hear in analog, the more squares waves you have (shorter slices) the closer you can approximate the analog wave.

Why use MP3:
MP3 compresses sound information to store in a more space efficient method than raw audio information. This compression does come at the price of “quality” as some information is lost in order to fit into a smaller space. The question becomes what is “lost” in your recording. Many people view modern encoders as being similar (Amorim). I leave this to your own personal preference and storage space constraints. I personally prefer the FLAC and OGG formats; however, many digital records do not natively record in this format.

Works Cited
Amorim, R. (n.d.). Results of 128kbit/s Extension Listening Test. Retrieved April 28, 2015, from http://listening-tests.freetzi.com/…/128kbps_Extension_publ…

Sony IC Recorder Operating Instructions ICD-PX312. (n.d.). Sony.

Supurovic., P. (1999, December 22). MPEG Audio Compression Basics. Retrieved April 28, 2015, from http://www.mpgedit.org/mpgedit/mpeg_format/mpeghdr.htm

Wilkinson, D. (2015, March 18). Meet the Musical Clairvoyant Who Finds Ghosts In Your MP3s. Retrieved April 28, 2015, from http://noisey.vice.com/…/yntht-there-are-ghosts-in-your-mp3s

 

Samuel Sanfratello

Samuel Sanfratello

My name is Samuel Sanfratello (Sam). I am a NY state dual-certified Mathematics and Special Education teacher and a nationally certified Consulting Hypnotist. I am also the proud owner and operator of two companies: Monroe Hypnosis and Rochester Analytics. I am a 2nd generation Spiritualist (American Spiritualism) and a certified Medium with the Plymouth Spiritualist Church (the mother church of modern spiritualism). I am an organizer of the Rochester Paranormal Researchers, founded in 2007 and a lead investigator for the Paranormal Science Institute’s F.R.I.N.G.E team. In my spare time, I give back to my community by doing volunteer work for my church and for my local chamber of commerce. I became interested in the paranormal when I spoke with a spirit in my grandmother’s house in the early 1980s. I enjoy reading publications and scientific articles about the fringe sciences and I enjoy sharing these understandings with others.
Samuel Sanfratello

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