[crwilli]

Here are my thoughts IMHO.

- 130Hz is too high a crossover point.
… Your Venere 3.0s go down to 38 Hz.

…At 130 Hz, your Fathom is operating at its limits.

…You don’t want to ‘hear’ your sub. Ideally you should not be able to locate it.

I would optimize the Veneres position to give you the best bass performance possible before ever hooking up the sub.

If you must stick with your sub in between the Veneres, at least have it flush with their fronts. Set its level to be about the same as your mains. Then start setting the crossover. I would start low and work it up slowly. Say 40Hz.

Most importantly, each time you set the crossover, you must readjust the phase to your mains. This ‘times’ the wave front from your sub to be the same as your mains. (Not absolutely but the best you can)

Do this by unplugging one speaker. Then reverse the connections on the remaining speaker. With a Friend, have them slowly turn the PHASE control on your Fathom while you are in your listening position, to a test tone just below or at your crossover point. (I find just below works best). You are listening for the bass tone volume to fall off to a minimum. At its lowest level, you will have adjusted the wave fronts for the sub and your mains. IF you have to turn the PhASE control past 180degrees, put it back to zero, set your other phase switch from 0 to 180 and repeat. Use whichever setting allows the PHASE control to be less than 180. Using a sound pressure meter makes this easy.

Now correct your speaker connections, reconnect the other speaker. RUN the DARO and listen.

You want to hear bass notes but not necessarily be able to locate the sub. If you can, it’s volume is probably too high.

Experiment