My main speakers are a satellite/sub system (NHT XDs). The sub is a legitimate powered sub, but does not provide for a separate LFE input. Therefore, when I configure my speakers - the mains are set to large, the center and surrounds to small with no subwoofer. Is there any disadvantage to this type of setup versus the more standard 5.1 configuration? For example, in my setup I cannot set the level separately for the LFE/subwoofer channel. Is that an inherent limitation?