Equipment:
Paradigm Prestige 75F (front right and left)
Paradigm Model Center 1 v7 (center)
Paradigm Model Surround 1 v7 (surrounds)
Paradigm Model Sub 8
Anthem MRX 520 receiver
Oppo 103D bluray/SACD player
Oppo PM 2 headphones
Panamax MR 4300
Blue Jean cables and wires
All firmware is up to date
I have run Anthem's ARC 4 times without being able to effect my issue. I have swapped cables, plugged components directly into different wall outlets to eliminate grounding issues or problems with the Panamax component.
Here is what is happening:
On most CD's this system kicks butt and sounds great. However, I am having issues with the sub when I play music that should not contain any low frequencies for the sub to play. Example: I listen to an Anonymous 4 CD (4 women vocalists) and I hear a very low frequency rumble coming from the sub. If I remove the grill, I can confirm that the driver is vibrating. It almost sounds like the noise a ventilating fan mounted on the roof of a building makes when you are in the building and can faintly hear it coming out of an air vent in the room your in. This low level noise on the floor of the recording can be confirmed listening with headphones. However, when I listen to a clavichord CD or a few harpsichord CD's the problem gets really weird. A clavichord does not really produce any low frequency sounds. However, when I play the disc I hear what I can only describe as a ghost image of the low frequencies of the recording being replicated at a much lower frequency level. It's as if the sub is receiving a signal of the lower frequencies of the recording that have been transcribed into a lower octave. The sub produces a lot of noise that is in syn with the recording but is not actually on the recording (confirmed with headphones). It sounds like the clavichord was placed on a large, hollow steel drum and your hearing the reverb effect it would have had had it been recorded like this. I know this sounds weird, but this has really got me stressed. I've heard this disc on other systems with a sub and this does not happen. I have configured the receiver with another speaker profile (front left and right only) that eliminates the issue completely, but I don't understand why I have the issue in the first place. This "noise" does not occur on any discs that have low end frequency material for the sub to play (rock, jazz, symphonies, etc.). It only happens on discs that do not have low end material in the recording. The sub's EQ is set to bypass, gain is at 12 o'clock, and I took a lot of time to ensure the phase was set correctly. After running ARC, the level calibration in the receiver for the sub is -2 db, so the 12 o'clock position on the gain is not that far off.
Any thoughts or insights would be appreciated.
Joe B
