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Subwoofer

PostPosted: Wed Aug 01, 2018 3:12 pm
by atugores
Good evening, I need some help to correctly install a new subwoofer (Presonus Tenblor T10) I just add to my installation.
I have a motu Ultralite AVB interface and I use 8 of its channels 2 for the Main with 2 speakers, 2 for the swell with another 2 speakers, and 2 for pedal (this with the new subwoofer, and 2 more speakers attached to an amplifier).
When playing the sound of the pedal this is not clear, it is like if it there was a continuos HUM............., and the listener is unable to hear a clear pedal sound, and more this HUM overpass the main and the swell sound converting the whole music in a confusing noise. the low pass filter of the subwoofer is set to 80Hz.
I am sure maybe I have this uncorrectly installed, does any one of you can give me a help on this, thank you.

Re: Subwoofer

PostPosted: Wed Aug 01, 2018 5:07 pm
by tf11972
What you are describing is a problem with room modes. Please look at here for description:

https://en.wikipedia.org/wiki/Room_modes

First of all you have to lower the volume of the subwoofer. The best one is that you recognize when it's turned off. The next step is the correct placement of the sub. Put it down somewhere in your room, let music play with deep bass and crawl across the floor. The place where the bass sounds best, is the optimum place for the subwoofer. You can also position bass traps in the room corners, but the best way to eliminate room modes is the usage of a room correction like ARC, Dirac or MiniDSP. There are many threads in the Forum about it.

Re: Subwoofer

PostPosted: Wed Aug 01, 2018 5:26 pm
by magnaton
Your Hum may be caused by your MOTU interface not being on the same A/C circuit as the subwoofer. On the back of the Presonus Sub, try flipping the Phase and or GND/Lift switches and see if the Hum goes away. Another trick is to eliminate the ground on the Sub (which I think the "GND/Lift" switch is support to do) by using an old fashioned A/C adapter that takes a 3 prong plug down to 2 (no ground).

Not sure I follow how your routing is set up. If you have 2 'standard' speakers dedicated to the Pedal division, then the sub should compliment it by using the Mix Down routing design in the HW Audio setup. Another design would be to have the Great and Pedal division share the same 2 or 4 channels (array) and have the Sub be a Mix Down for just those 2 division or a Mix down for all divisions, YMMV. Review the specs of your other speakers to review what the lowest frequency they can produce then adjust the cut off on the Sub accordingly.

Danny B.

Re: Subwoofer

PostPosted: Thu Aug 09, 2018 1:55 pm
by atugores
Thanks for you help I follow your indications but I still have bumpy sound, I'll keep trying