Originally Posted by jamato8
What people might also want to think about is why is the iphone putting out so much RF and what will be the effect on their brain? That is of greater concern to me as a health professional than interference on the sound but maybe the D3 is telling you something.
Originally Posted by paulybatz
Larry, being a DJ as well...my verizon phone never interfered with my PA system but cingular/ATT is aweful...it also interferes with my sons baby monitor. Anyway, thanks for helping to sustain my disdain a bit. I will likely keep the D3 and use it as a DAC and figure something else out for portable...or just buy a regular ipod.
The reason that GSM phones tend to interfere more than CDMA phones isn't the total RF power, but the fact that GSM is always rapidly switching the transmitter on and off. If you have a non-linear device, some of this RF energy is going to be rectified into DC. If the RF is turning on for ~0.5ms every ~4.5ms, that DC is going to switch on and off very quickly and cause a lot of noise.
I can't comment on the total power used by 3G devices, as I am not too familiar with them. All other things equal, the faster you're transmitting data, the more power it takes to overcome noise. But not all things are equal between 3G devices and older devices, so I hesitate to draw any conclusions here.
Some RF is probably coupling from the iPhones transmitter into the audio output, as will always occur in such a small device with a minimum of shielding(who wants to carry around an 80 pound metal brick in their pocket...I doubt even most audiophiles would go that far
). I wonder if iPhone is worse than any other music-playing phones in this regard. You could try adding some filtering between the phone and the D3 and see if that helped. I mean, filtering out the 800+ MHz range isn't likely to cause too much pain for audio.