I got
these Axminster ones last time. They are very good - comfortable, even with glasses and headband magnifier on, and good, fully-documented attenuation. They also pack up small (my other 'official' cheapo set doesn't).
I also occasionally use these:
with the cable removed (it unplugs from the cans). They're a bit expensive for throwing around the workshop, but they do work well.
Don't take risks - permanent hearing damage is done far more quickly than people imagine. This is scary:
Roughly explained, the graph indicates that the "carpenter's" hearing is already
one sixteenth as sensitive (at 6kHz) as it should be, and the 55-year-old craftsman is profoundly deaf! That frequency, 6kHz, is important for consonants in speech - the 25-year old would already be in trouble with speech in noisy surroundings unless he (she) could lip-read...
For really aggressive noise, such as hours of routing or planing or hammer-action tools, wear good soft earplugs (from a chemist) under the defenders. Impulse and loud higher-frequency sound (stuff hitting other stuff, including planer knives, hammer drills and firearms, drum kits and electro-pop) causes hearing damage fastest. Also don't under estimate the damage of heavy hammering - it's not just hitting your thumb!
E.
. . . . . .
Long PS: I forgot to say:
For those who don't know, the decibel scale ("dB") is a logarithmic measure of relative 'bigness' (it's used for a range of things other than sound). To a layman, the 'logarithmic' bit means it goes up as the square of the change (very,
very approximately).
- "dBA" uses a specific loudness reference to give an absolute measurement of sound power.
- "dB" is relative (it has no "A"). It means how much bigger or smaller a difference is.
This is poorly understood, even by manufacturers, who often produce misleading/incorrect data sheets, etc.
Some reference points:
- a 3dB change is a halving or doubling of sound power
- 125 dBA is considered to be the threshold of pain, but it's a bit arbitrary.
- Sound louder than 135 dBA causes instant damage. How badly depends on how long you're exposed to it in one go, and overall (all exposures added up).
- With the possible exception of lightning, there aren't any impulse sounds in the natural world with a large high-frequency content - these are almost entirely man-made. The ear protects itself well against large, low-frequency noises, but is vulnerable to high-frequency ones.
- There is no really safe level of ambient noise. Tests on sub-Saharan tribespeople (where it's really quiet) show that hearing doesn't deteriorate much naturally over a lifetime. Almost all 'old-age' hearing loss is actually environmental damage or disease.
- A 1970s study on Soviet workers at a drop-forge showed that high-level impulse noise causes permanent damage very quickly indeed.
- Digitally recorded music tracks played on personal stereos (with 'earbuds') can be as damaging as power tools. Listening to music under ear defenders in a noisy environment is a really bad idea, for any number of reasons, not least hearing damage.
http://www.cdc.gov/niosh/topics/noise/ is a really good reference site, but, as an indication of how poorly the subject is communicated, in the first PDF I opened from there,
every reference to decibels used the terminology incorrectly -- the author clearly didn't understand what he was writing about! There are better bits though, and it's worth looking through. This is especially useful:
You can blow big holes in the above (technically, it's like comparing the national debt to the size of Wales), but it's a useful rule-of-thumb guide. Note the hammer drill especially.
E.