Subwoofer tweaks

@cmach   My two DD -12 Plus rest on birch plywood dolly's with extra-soft casters. The dolly's are topped with four inch layers of dense latex foam and approximately three inch layer of closed cell old Morey Boogie board foam. 

I needed to rerun the Auto EQ and slight manual preset tweaks to maintain desired frequency parameters.

The decoupling greatly reduced the extra low frequency transmission throughout our dwelling while actually providing a more desirable presentation. I'd say elevating the units may have played a roll in the presentation itself. 

Having owned a DD-18, I recall the manual didn't convey the importance of room positioning.  

The manual made mention of walking around room with the mic and noting the greatest frequency spike while viewing the graphic display during the Sweep Tones, (page 23?).

With the DD Plus the subwoofer crawl is step one out of the box. Proper room positioning requires far less use of processing parameters and noticeably better synchronization with the room and the main speakers. Your DD is still a great unit.

@secretguy - you responded to @9rw’s post from 18 years ago, better late than never, I guess

Also try some weight on top of the unit, Tames resonance. 

@mitch2 Hahahahahahaha!!!! Well all part of the Encyclopedia Audiogalactica!!

Rythmik F-25's owner here. While I have tried and heard many a sub throughout my audio journey, here are some observations/thoughts I wouldn't mind sharing with you this afternoon. 

I prefer front firing, sealed subs.

Adjustments to the mains, as well as to the room are critical. 

Raise the height of the subs for optimal impact/ system performance.

Having subs in stereo is much better than just having one sub.

Isolation control is very beneficial. 

Never, ever underestimate the impact of IC's and PC's that go to the sub(s). 

There is no replacement for displacement.

Low excursion drivers seem to offer tighter visceral impact (not Boom).

IMO, direct servo subs are the most accurate for 2 channel listening. YMMV.

For front firing subs, they must be placed with the same precision as the mains. I am referring to toe in on this one. Not just haphazardly placed. Precision is key here. 

These are just my observations. If you want to argue, I will ignore you. That said, if you would like to discuss? I'd be more than happy to engage in a cordial conversation.

Tom