Another sub build. rs390ho's

[aprilia88]

I bought two rs 390's while they were on sale last week. I like the idea of opposing woofers in the same cabinet. would that help out room modes?
It looks like seald box 60l per woofer is what most people have been using for these.
How much room gain can i expect on the low end?
And one final question, Are there any plate amps that are 2 ohm stable?

[ThomasW]

would that help out room modes?

Nope they would function as one sub

How much room gain can i expect on the low end?

Depends totally on the geometry of the room and the construction materials used in the room.

The room mode, RT/60 spreadsheet on the link below will give you some idea.

http://home.comcast.net/~thomasw-2/SubwooferSetupandEQpage12.html

And one final question, Are there any plate amps that are 2 ohm stable?

Some have used various 240/250 watt PE amps to run 2 ohms (not the BASH amps) . That load certainly isn't recommended.

[joecarrow]

What the two subs firing in opposition will do is cancel out the newtonian reaction force that would shake your cabinet back and forth. Most sub cabinets are fairly heavy in relation to the cone, so this doesn't generally offer a huge improvement to the sound. If you mount them so that one magnet is in the cabinet and one magnet is out, then some of the even order distortion is reduced. Just make sure that they are wired in opposite polarity such that they both move into and out of the cabinet in unison.

A lot of folks around here use pro amps to power subs. They offer two channels, and are often capable of working into really low impedances. In your case, I'd say to get a pro amp (Behringer EP1500 is popular) and run one channel to each driver.

It's also a good idea to get some equalization to take care of the in-room response and give a boost at the lowest frequencies- assuming you have the Xmax to handle that and the box and room don't give you enough to start out with. The Behringer Feedback Destroyer Pro is a popular choice for this task:

http://www.partsexpress.com/pe/pshowdetl.cfm?PartNumber=248-656&raid=43&rak=248-656