20dB Hearing Protection / Headphones - A Fun And Useful Project
The following pictures outline a small project you may be interested in. Listening to music through
headphones is great when you are in a quiet environment. As often the case in life though, external sounds
may not only interfere with your listening experience but may also cause you permanent hearing loss. Using
a loud lawn mower, or working in a noisy factory are just two examples where isolation headphones work
great. Not only do these headphones block out 20 dB of the external sound, they also double as a nice way
to allow you to enjoy music at the same time.
Some sponge and velvet was used to make the
headset more comfortable. With the outer
velvet removed, you can see another red ring of
velvet. I had to glue that red ring on because
without it, I found the outer black velvet was
slipping off the smooth learther like skin of the
original hearing protection. The black velvet
was cut from a shildrens shirt purchased at a
used clothing store for $2. They were actually
the sleeves of the shirt, which just so happened
to be a perfect fit for the headphones.
The inner pink sponge is removed to expose
the speaker which is protected by a metal
shield. The sponge provides a soft feel on the
ears for extended listening. The shield protects
the speaker from being pressed against by the
sponge.
Here the speaker is removed and can be seen.
This is a 40mm driver which someone at school
was nice enough to give to me. Originally I put
in a pair of 30mm drivers and they lasted for a
few months until one day the left driver
suddenly stopped. The extra green sponge was
put inside to eliminate the hollow, sea-shell  
sound effect that would be produced without it.
This photo shows the hearing protection which
was converted into a pair of headphones. I built
these because while listening to music in a noisy
environment I found myself competing with the
noise by turning up the volume of the music.
This was not good for my ears. This set of
hearing protection was purchased at a hardware
store in Toronto for $18. The speakers which
were put inside originally came from apair of
regular headphones. Overall, the isolation
headphones sound alright but have some
difficulty playing back the low frequencies.