my sub will work with the front left , right eq settings but not the sub eq settings. is there something i need to know? I tried stereo + sub and direst modes for 2 channel music

Just trying to clarify, are you saying that you don't perceive the eq settings are making a difference to the sub or that the sub is a missing channel? Are your Left/Right set to "small"?

Bass in a small room can often be beyond the ability to manage with EQ due to room modes and nulls.

no i want the eq. the main speakers are set to small and crossover 40 hz. i can get the eq to work with the main channels but not the 10 band eq for the sub when playing music in 2 channel. ( direct or stereo + sub )

Try setting a really high crossover point (200hz) and see if you can EQ a noticeable bump or cut at 100hz.

Post #97890 from Outlaw Ben (March 8, 2018) clarified something that applies here as well: The EQ is applied only to the source channels, then the crossover diverts the low pass to the Sub. For a stereo source the EQ only applies to the L/R channels. Even though the LF will come out of the Sub, the sub channel's EQ only applies to an LFE source channel. I think this sounds like what you observed?

Good news: you get to EQ for each individual source channel and how it's bass management is handled in combination with the sub. Bad news: this eats up bands in the PEQ on each channel instead of just the LFE channel EQ.