Scent, sight, and sound… 

Two of these — scent and sight — are topics that have been covered quite a bit over the years when it comes to ground blinds and their effectiveness in limiting an animal’s ability to pick you off. On the flipside, I have found very few articles about ground blinds and sound, and I’m not sure if I’ve ever seen an article explaining just how much quieter you can be when you use a ground blind.

So how much does a ground blind actually dampen a hunter’s sound?

As developers and manufacturers of ground blinds, we were very interested in this topic. And since we couldn’t find any data on the subject, we decided to run our own tests. Through my experiences in a blind, my gut told me the blind would definitely cut down on the sounds of a hunter’s movement – reaching for your bow, adjusting position in your chair, or grabbing a pair of gloves out of your backpack – but was it as significant of a sound reduction as I assumed? Perhaps some sound tests would shed some light on it.

These being the first sound tests we had ever performed, we performed the tests in XENEK’s warehouse using an iPhone and a decibel measuring app. We felt this was an adequate way to capture out initial results, knowing we could always utilize more sophisticated equipment if we thought it could give us better information and allow us to make more accurate conclusions.

The Experiment

We first set up a Bose speaker in the warehouse that played a 60-second recording (found on YouTube) of someone whispering. We then placed our sound level meter 8 feet from the speaker.  We had initially performed some preliminary tests outdoors but soon realized the variability in the ambient (background) noise made it difficult to accurately measure the sound level of the whispering, so the test was moved indoors into a better-controlled sound environment.

Once set up inside, our goal was to take three 60-second readings. The first reading would measure the sound level of the whispering without the use of a ground blind. The second reading would measure the sound level of the whispering while inside XENEK’s Apex ground blind. The third reading was simply to record the ambient noise within the warehouse, so we could then subtract this sound from the other readings, giving us a true comparison of the two sound levels, which would then show us how much the noise level is reduced by the shell of a ground blind.

The Results

Here’s what we learned:

• The average sound level over the 60 seconds of whispering without a ground blind was 36.1 decibels.
• The average sound level over the 60 seconds of whispering inside the Apex blind was 31.3 decibels.
• The sound level for the ambient noise in the warehouse was measured at 30.7 decibels.

At first glance of the results, you might say that they’re all relatively close to each other and all fall within 30 to 36 decibels. However, remember that the decibel scale is not linear but logarithmic.  This means for each 10 additional decibels, the sound is 10 times louder. For example, 40 decibels is 10 times louder than 30 decibels. Therefore a jump from 30 to 36 decibels is more than twice the sound intensity.

However, before we can compare the sound of the whisper within the blind to the sound of the whisper outside of the blind, we have to subtract the ambient noise level from each. Again, because the scale is logarithmic, the values must first be converted to a linear scale before they are subtracted, and then converted back to a logarithmic scale.

For example, subtracting 30.7 dB (ambient noise) from 36.1 dB (whispering without a blind):

L = 10 log₁₀ (10^3.61– 10^3.07) = 34.7 dB

And subtracting 30.7 (ambient noise) from 31.3 dB (whispering inside the Apex blind):

L = 10 log₁₀ (10^3.13– 10^3.07) = 22.3 dB

Subtracting the ambient sound from the two whisper tests gives us the following results:

• The sound level produced while whispering outside of a ground blind was 34.7 decibels.
• The sound level produced while whispering within a ground blind was 22.3 decibels.

With the sounds level within the ground blind registering at more than 10 decibels less, this means that by the time the sound gets to the decibel reader, the sound generated inside the blind has one-tenth of the intensity of the sound generated outside the blind.

Can a ground blind really reduce your sound level by 90%? 

While that sounds a little too good to be true, you have to remember the human (and deer/elk/antelope) ear is extremely sensitive and able to hear an incredible range of sound.  Keep in mind that the sound of a jet engine is 1,000,000,000,000 times louder than the smallest of sounds that the human ear can hear. Understanding the amazing range our ears can hear, a 90% reduction in sound makes a little more sense and is a reasonable result from our test. 

Noise level, hunting, and you. 

I would consider this a fairly crude test, and to get more precise results, I believe tests would need to be performed in a more controlled environment, such as a recording studio. However, what our crude test results are able to show is a significant reduction in sound when hunting from a blind versus hunting without a blind or hunting from a tree stand. If you believe in the power of eliminating as many variables as possible that could wreck a hunt, you may consider a ground blind over a tree stand to reduce the sound approaching animals may pick up on as they work their way into a shooting lane.

Noise level, hunting, and XENEK. 

Better understanding how fabrics can help dampen noise from inside a ground blind will help us source fabrics that have better sound dampening characteristics as we develop new products and improve products we currently provide.