All these posts are excellent. I am about to purchase my second set of H/A's, and will go with the Cobalts 12. As it regards to the fidelity expected from a H/A design to amplify specific frequencies to the point of a High End pair of headphones, I think it is too much to ask.
The normal use of H/A is to increase high frequencies, which are the first ones we lose (at least for 80% of us with hearing loss issues). Thus, the H/A receiver is not designed to handle (or boost) low frequencies. So, using it as headphones, you would expect to hear the music, with emphasis on the high frequencies (more than 1,000 Hz, or the singer's voices and higher pitches). The bass and low tones will be heard, but not as strong (or loud) as the mid and higher tones.
These Cobalt (which we now know are the Siemens Pure copies) are designed for the hearing impaired, to help us hear sounds others can, and they do their work excellently. We look for H/A that are as insconspicous as possible. In order to make them sound as good as a GREAT headphone set, they will need to be as BIG as those headphones are, which is in contradiction with the low profile design of the H/A.
Another point of clarification: The connection between the Blu RCU (TEK connect in Siemens) remote and the H/A is not via Bluetooth (BT). Siemens developed their own communication protocol to avoid interferences with other audio devices. The BT connection is between the Blu RCU and the other devices (phone, iPod, TV). And the only reason to have it hanging from your neck (or your shirt's pocket) is if you want the microphone close to your mouth (that is how you use the phone connection), otherwise, you can have it in your purse or your pocket, and the music will still be heard, WIRELESSLY, in your ears. That is the true convenience of it.
Bottom line: There are no device designed to allow you to connect wirelessly to your existing H/A. You will need to purchase new technology H/A that can connect your iPod wirelessly to your ears.
Best regards,
Ahmed