So the biggest question is: Does the DSP really make that much of a difference? Well, once we established a connection, sound quality in the earpiece was very good and loud. Riding down the street with the windows opened we were still able to hear the conversation on the other end with very little problems.
Of course the DSP should only come into play when the user is speaking to ?reduce noise levels? for clear sound and conversations. This wasn?t always the case in our use. Many times, the person on the other end of our conversation would complain about apparent static or other anomalies like ?the transformer effect?. After either resetting the connection between phone and headset or hanging up and calling back, the static would clear up. Of course this doesn?t happen every phone call, but it happened enough that we wanted to make sure we pointed it out.
Another test that we like to do at Legit Reviews to test sound quality is to try and hold a normal conversation in the car with either the windows rolled down, or the radio turned up. For headsets with noise reduction, this serves as a good test to see exactly how well they function. With Plantronics implementation of a digital signal process to the voice transmission of their Discovery 655, we thought we would see a dramatic improvement. Unfortunately, our background noise tests exposed the 655 and brought it to its knees.
With the windows down traveling no more than about 55 miles an hour, there was enough wind picked up through the Discovery?s microphone that we could barely hear the voicemail recording we created. With the radio up fairly loud, we had similar results: The conversation was barely audible over the background noise. During normal conversation, I found myself holding up a hand to sort of cup the earpiece to direct my voice to the 655?s microphone.