Headphones This page features information about headphones. Note: I have not received any compensation or motivation to write about the Koss Porta Pro, or Shure E2C models. I am simply sharing my knowledge and experience for the reader's benefit.
The Koss Porta Pros
Here is a picture of the Koss Porta Pro headphones. For under $50, these are my favorite pair. If you visit a major Internet search engine and type in "Koss Porta Pro Review" you'll find many people who are crazy about them. The Porta Pros have a nice frequency response with outstanding bass. Some people say the low frequency response is too strong so it's a matter of opinion. I happen to enjoy bass very much and don't mind. I believe that Koss has not changed a thing about these headphones in over ten years now. The drivers used in the Porta Pros are also used in the Koss Sporta Pro, KSC 35, KSC 50, KS5 55, and the KSC 75 models too. Koss simply puts the same speaker into a different style package. 
More pictures and information about the Koss Porta Pro headphones.
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Using In-Ear Phones
Many of us will be in a situation some time where we would like to 
enjoy listening to music but there is just too much external noise in 
the environment. In cases like these having a pair of in-ear phones can really help. One of the best features for in-ear phones is their ability to block out about 16-20 dB of the external sound. They also  wrap up into a small package making them great for when you are out on the go.
More pictures and information about using in-ear phones.
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Some Information About a Pair of 20dB Isolation Headphones You Can Build
Pictured on the left is the result of a small project you may be interested in. Listening to music through headphones is great when you are in a quiet environment but sometimes external sounds may not only interfere with your listening experience, they may also cause you permanent hearing loss. Using a loud lawn mower, or working in a noisy factory are some examples where isolation headphones would 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.
More information about  the  20dB isolation headphones you can build.
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A Way To Modify the Koss KSC-50 Headphones to Improve Sound Quality and Comfort
Here is a picture of a pair of KOSS KSC- 50 headphones which I purchased on eBay. These headphones were less than U.S. $10. These are great sounding headphones, namely because they use the same speaker from the KOSS Porta Pro line, just put into a more "sporty" housing. However, they are uncomfortable to wear, and because there is a gap between my ear and the headphones, a lot of the bass is lost. To fix this, the KSC 50 drivers were put into a better headband. The result was a much more comfortable set of headphones, and a better low frequency response.
AFTER
BEFORE
More information on how to modify the Koss KSC - 50 headphones.