Hello, twinsrx. My guess is that the subwoofer output on your receiver needs to be modified, or that your KEF sub is defective. After reading the owner's manual for your KEF sub, I saw that it has no volume control (with the exception of the two bass boost options). Therefore, the output of the sub is controlled almost exclusively by the line-level input coming from the receiver. My guess is that you have the speaker settings on your receiver set up correctly because the Boston Acoustics sub is working fine (but I suggest that you double check them anyway), but you might need to increase the subwoofer signal output level from the receiver for the KEF model.
