Need Advice - DYI HT Sub


Novice Member
I’d appreciate some advice for where to find a HT sub design that would fit my goals.

I have a family room that is approximately 16’ x 22’ with 9’ foot ceilings (3,200 cu ft), and next to it is a game room that is 12’ x 15’ (1,600 cu ft). The rooms are largely open to each other. In the family room there was at one time a fully built-in large projection TV enclosed with drywall and cabinetry on either side, so I have a space that is 48”W x 30”D x 52”H which is largely open for a sub, just a flatscreen in the front of it with 15” below the TV for a sub to project although behind the flat screen much of the volume is empty. This location is also in a corner of the room and projects back to the opposite corner and also into the game room.

The area that’s exposed under the TV (will be covered with audio cloth) is approximately 15”H x 40”W if leaving room for trim, the actual sub box sitting behind the trim could be higher.

I’m looking for a solution that is weighted towards sound quality (movie sound tracks, online concerts) but want enough bass to make action movies exciting, but don’t need to blow out windows. For this reason I’m leaning towards an sealed sub (also simpler to build).

I’m thinking a 12 – 13” driver (or larger?) and am willing to spend up towards $800 all in (driver, box, power amp). The rest of the system has small bookshelf mains (Paradigm reference 20s), center, surrounds etc.

My questions are:

  • Is there a ready-made design that would work
  • What are driver recommendations
  • What are amp recommendations
  • Is there a concern having the sub somewhat enclosed on the sides and top will affect the sound quality (there is a fair amount of air movement through the wide cloth grill and around the TV)
  • If the driver is 12 or 13” and the opening between horizontal wood trim is 15”, is this sufficient for the driver to properly project without interference.
  • Your thoughts on the cost/benefit of building two units (each cheaper than $800) and having a second sub behind the listening sweet spot.
Really appreciate insights from better minds than mine.


Well-known Member
Dont know if you would entertain importing a driver but the CSS sdx12 xbl2 is available from partsexpress in the US.fantasticly reviewed driver with a low distortion motor.amp wise, maybe a crown xls1502.and ask Gordy on ebay to make the box to your design.


Well-known Member
Looking at your profile you are in the US, which is a bonus because you will save a load on shipping (compared to shipping large heavy stuff to the UK, where this forum has the majority of its members, I believe).

Stereo Integrity are restarting their HT18 line again soon, with a 'v3' version for something like $199 shipped:

Stereo Integrity HT V3 coming soon

Couple of those for $400, add an amp for about $400:

Amazon product (this one includes DSP for response shaping)

and then add a dual-opposed box (to cancel box movement) ($200 for MDF??) and cabling / connectors / paint etc ($100?).

That would take you to, er, over a grand... lol

Would be decent, though :) I've very happy with the SI HT18s I'm running!


Well-known Member
Oh, I forgot to say - having the driver close up against a wall should not be an issue.

IIRC it lowers the Fs (resonant frequency) of the driver/box, which means it plays lower more easily - or something like that... lol

I've got my 18s in a slot-loaded setup and they are currently facing the wall, so only have about an inch gap between the slot exit and the wall. Zero issues with sound transmission ;) as the sound waves are so long as to 'wrap around the box' with no issues.


Well-known Member
  • Is there a ready-made design that would work
  • What are driver recommendations
  • What are amp recommendations

Have a look here at GSG Audio Design, you should find all the answers you are looking for:

And the AVSForum thread if you want more info:

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