I recently received a set of BONE CONDUCTION HEAPHONES from FRED w3njz, to evaluate for listening to qrq cw. This set was one of the cheapest found on the internet and one of the few that were actually for sale in the USA.
You can buy this headphone on AMAZON
Here is another site that describes this headphones and its features:
On first impression I was quite pleased with the quality of the cw copy while using this headphone. The cw was very crisp and clean and without the usual background hiss that you hear while using air conduction headphones. It takes significant more energy to activate the bone conduction wavefront than it does to
hear the same volume level while using air conduction. Therefore, any background noises that are present will not be strong enough to discern while using the bone conduction pathways verses the very sensitive air conduction pathway, where the slightest hiss, hum and noise will be perceived by the brain. This actually is quite a plus when copying cw, since the requirement for more energy to be present while using bone conduction, will filter out any extraneous and unwanted sounds that are below the volume level of the actual cw tones.
To get this headphone to seat properly, you have to press the bone conduction transducer to your skull with your fingers. The current design does not seem to work well without applying additional pressure with your hand to seal the vibration mechanism for good bone conduction to take place.
There is another bone conduction headphone that might be the answer :
TEAC’s skull vibrating headphones now featuring hi-fidelity audio
Audio | Gadgets | Gear & Wear | Wednesday, April 25th 2007
Bone conducting headphones (yeah, that’s your skull vibrating) has been around for a while but TEAC HP-F100 Filltune is the first pair to reproduce hi-fi audio. One of the benefits from having the audio conducted through your bone is that you can listen to extremely loud music without worrying about deteriorating hearing.
Besides being foldable and light the headphones ships with a portable amplifier sporting a 10-hour battery life and .76-watts to each channel.
AudioCubes.com: TEAC HP-F100 Filltune ($499.00)
Since the price is almost the cost of an HF rig, I will have to wait to review this one.
I think the concept is solid and has many advantages for listening to qrq cw.
The bone conduction spatial effect of having the cw audio centered was a nice feature. The sound just "appeared" inside your head, right in the center.
No pressure pushing on your ears...
No "heating build up" since there are no "cans" around your ears ...
No single tone, ear drum burnout, from 750hertz pitch notes slamming it around...
No damage to the eardrum components from a loud burst, bone conduction
bypasses that sensitive air conduction circuit
Natural noise filtering inherent with the bone conduction pathway
Crisper, sharper cw notes without clicks or other irritating noises like hiss, hum, and
fuzziness from artifacts from audio processing