Plantronics Encore H91N Headset

I am really appalled that a headset in this price range would have such poor quality. I used it in combination with Plantronics' M12 Telephone Headset Amplifier. I expected the best possible sound one could get over a phone, but instead got something worse than a normal phone handset, and worse than a cellphone earpiece plugged into a cordless phone.

The caller sounded distorted and fuzzy. I had to ask him to repeat himself many times. To him, I sounded tinny. I tried various volume settings and tried playing with the tone control in the earpiece; no help. In the same call, I switched to the phone's normal handset and the sound returned to acceptable quality.