Hi, about a year ago I purchased an Onkyo HT SR800 HTIB.
I have been very happy with the system and have since upgraded the receiver for the HDMI repeater and HD codec support. The only piece I have become unhappy with is the sub.

I notice particularly when viewing scenes in movies like Cloverfield, there will be sections that seem to go very low and it will distort the bass.

I am not savvy at all about audio and subs and would like some recommendations on what specs to check for.

I have a relatively small room: 8ft high, 10ft wide, 20 ft long. I also have some glass display cases in the room and don't want to be shaking the hell out of them.

Aesthetics don't matter much to me.

The purpose of the sub is for movie viewing almost exclusivly, video games as well.

I want something better than my current set up that will handle all the bass I will encounter in Blu-Rays cleanly without distortion and give the appropriat amount of oomph!

Current specs on my sub:
10" (25 cm) cone
25 Hz-150Hz
230 W
140 mV/20 k-ohms

What do I want to be looking for for the appropriate step up?

Thanks in advance for any response.

Budget?

Would like to stick under 400 but know that may be unrealistic if I want real improvement. Definately want to stay under 500.

SVS PB10-NSD www.svsound.com
eD A3-300 w/ Upgraded Driver www.edesignaudio.com
Hsu VTF-1 www.hsuresearch.com

Thanks, I had the A3-300 as my choice for a while but then it seems to have disappeared from their site. Any idea where it went?

I just checked out the specs on the VTF-1 and have a few questions:
It seems like the continuous amp power wattage and Frequency response are worse than what I currently have with no change to the size of the woofer.

My friend told me that to get rid of the distortion I should get a larger woofer (12 instead of 10) that has a lower Frequency Reponse (18 instead of the 25) or to up the wattage (250-300 instead of 230).

Which of these is really the thing that I should be looking at to fix my distortion problems?

I have the 20-39PCI and it is a little more ..at least for us Canucks...but it works quite well has the larger woofer and more power...check the specs..and the water heater look is a great conversation piece...and mamma has learned to love it...once I fired it up...

SVS PB10-NSD www.svsound.com
eD A3-300 w/ Upgraded Driver www.edesignaudio.com
Hsu VTF-1 www.hsuresearch.com

Agree with those, and let me add:

Outlaw (designed by HSU)

I would also recommend the entry Epik but who knows when they'll be in stock again...

Wait! I remembered something! Outlaw LFM-1 EX for $519 shipped! Best sub you can get for just a bit over $500. It's pretty much the same as a Hsu VTF3-MK3.

The VTF-1 will crush your current subwoofer. The 230 watt rating on your current sub looks like its max power rating. The 200 watt rating on the VTF-1 is RMS which means that its max power rating is probably in the vicinity of 600 watts (someone correct me if I'm wrong). As for frequency response, the HSU is flat +/-2db to 25hz. I don't see any additional details for the Onkyo sub, which questions its ability actually to hit that low.

On another note, the VTF-2 MK3 is on-sale for under $500 (before shipping).

I concur that the Outlaw LFM-1 EX is your best option. Although, they are back-ordered at the moment, so you would have to wait 45 days or so. It really is an incredible deal.

Thanks for all the responses! I appreciate all the recommendations. So as for the cause of the distortion is it due to all of the specs on my current sub being insufficient or just a particular part? Maybe without more info it would be hard to say but I would like to learn as well as just get a buying guide :)

For the area that I most notice it, if you play the Blu-ray of Cloverfield, right during the production company logo there is some heavy bass that gets deeper with each beat. About the last two or 3 beats distort terribly. Also when the beast first walks through when they run into the convenience store and crouch in the dark. It is walking past and everything shakes, I get bad distortion there as well as a few other places.

Thanks!

Wait! I remembered something! Outlaw LFM-1 EX for $519 shipped! Best sub you can get for just a bit over $500. It's pretty much the same as a Hsu VTF3-MK3.
There is one big difference, and that is the port diameters. The Outlaw uses 3" ports, the Hsu uses 4" ports. The Hsu will move more air at port tuning.