Audio Recorders: A Look At
Sampling Rates and Functionality
By Tony Hebert
Often times
in the field of paranormal investigating, a pressing
“Holy Grail” often sought is superior audio quality.
After all, EVP’s (Electronic Voice Phenomena’s) are not
much good if you cannot hear them. The question one must
consider is this: Is clear audio the absolute best for
in-field research? There are two aspects one must factor
in order to properly answer this question: sampling rate
and functionality.
If digital
is the route you choose, you must consider the sampling
rate and the frequency response of your voice recorder. A
sampling rate is defined as the number of samples per
second that is taken, or sampled, from one continuous
input source. Simply, an increased sample rate can filter
out “un-pure” audio. Examples of sounds that a sample
rate can filter are wind noise, sixty cycle hum, a dog
barking in the distance and EVP! A recorder that offers
noise reduction and clear audio is a recorder that uses a
high sample rate. This feature is great when intended for
school use or for office/professional use, however, high
sample rates are not the friend of the paranormal
investigator. In essence, we as investigators are looking
for that “un-pure” sound, that imbedded sixty cycle hum,
that realm of frequencies that hides our sought after
EVP’s. More and more of the major manufactures are doing
away with recorders that do not have high sample rates.
Observe your local electronics stores’ stock of voice
recorders. Most products now boast high quality settings
that provide “exceptionally clear audio quality.” These
settings are decreasing our ability to capture electronic
voice phenomena. In addition to sample rates, frequency
response, or the frequency range recorded, also plays a
key role in one’s search for an audio recorder. It is
theorized that EVP’s are recorded at hertz lower and
higher than a humans normal range of hearing, 50Hz to
14kHz; thus explaining why EVP’s are not heard live, only
when listened to on your recorders play back. Frequency
response is often noted as a range between two numbers.
For example if the microphone for your voice recorder has
a frequency response of 200Hz to 50kHz, then the
microphone for your recorder is able to reproduce sounds
occurring in the frequencies 200Hz to 50kHz. Anything
outside that noted frequency response would reproduce to
a lesser extent and most likely not reproduce at all.
With this in mind it becomes imperative to match a low,
or non existent, sample rate with a broad, or flat,
frequency response. This match generally can be made with
recorders that are priced fewer than forty
dollars.
Most
recorders on the market today offer a wide array of
“extras” for the consumer. The major brands, Sony,
Olympus, RCA and Panasonic of course, have all of the
same basic functions such as Record, Play, Stop, etc.,
however, there are some that offer direct USB transfer of
your recorded audio. The ability to transfer the audio
from your recorder directly to your computer, without the
use of wires or cables, can save a great deal of time for
the paranormal investigator. Ease of transfer not only
enables an investigator who may have multiple
investigations the ability to “clear” their recorders
before the next, but the USB function also gives the user
the option to use his recorder as a storage device, or
“Jump Drive.” Quickly clearing recorded audio and the
option to store files and images as well makes for
versatile tool in any investigators bag. However, one can
operate just the same with digital recorders that do not
offer USB connectivity or with analog recorders.
Transferring audio from an analog recorder or recorder
with no USB output to a computer is relatively simple,
however, this download must be done real-time. This
process requires one to insert a mono cable to in the
recorders’ earphone jack and the other end into your
computers’ microphone jack. This also requires software
on your computer that will enable you to store the audio
you are transferring; such software is NCH’s WavePad and
Audacity. These two programs cost fewer than fifty
dollars and provide excellent software options for the
paranormal investigator. During investigations, any
investigator can tell you that the possession of a
recording device that will enable him to record for as
long as the investigation takes is invaluable. As
technology grows, we see the trend for recorders to
constantly increase in time allowed for recording.
Recording time is specific, of course, to which media,
either analog or digital, your recorder records to. With
analog, cassettes and micro cassettes will afford one, at
most, ninety minutes of recording time. Digital voice
recorders offer a cornucopia of time allowances with
options ranging from seven hours to 144 hours.
Central
Oklahoma Paranormal Studies has had extensive experience
operating with recorders that have a high sample rate,
like the Olympus WS-300M, and those that do not, as found
with the Sony ICD-B120. After six months of
experimenting, we have found that high sample rates and
acute frequency responses do indeed alter one’s ability
to capture and record EVP. In short, lower priced
recorders tend to capture EVP much more effectively than
higher priced recorders. However, the “extras” that come
abundant on higher priced recorders, such as USB
connectivity and the ability to use the recorder as a
mass storage device generally will not be found on the
lower priced recorders. This has proved to be a worthy
sacrifice, allowing us to continue our efforts to capture
EVP, in hopes of explaining the unexplained.
Tony Hebert
Director
Central Oklahoma Paranormal Studies