Quote:
StephenP wrote:
 If you make a cable with a male rca on one end, going to the pin and ring of a stereo 1/4 inch plug on the other end it will break the ground loop (at least it did for me) |
I thought this was a good idea to try, but it didn't work for me. In fact, the hum got a lot worse. I also tried to use narrow filters on the BFD to kill hum, and that did work in a fashion. The main problem was that I had to use either half the filters just to get rid of the hum (and even then some harmonics got through), or two really wide/deep filters that encroached on the subwoofer's frequency range.
In the end, I engaged the subwoofer's built-in crossover set to its maximum of 120 Hz and that almost entirely eliminated the hum. What little was left is all but inaudible. I had to rerun REW to check the sub's response to the extra low pass filter but it was set high enough that little change was required. Yes, there is double filtering going on, but the end result is worth it, especially when the alternative appears to be buying yet another $100 piece of equipment (the Jensen transformer) to fix issues with the first $100 piece of equipment!
BTW, here are before and after graphs of the primary listening position. I didn't correct for everything, only those things that appeared in the graphs of all three measured positions. For instance, the suckout at 110 Hz disappears entirely only three feet away to either side. So does the hump at 40 - 60 Hz. I'd appreciate feedback. Thanks.
Before:
After:
