Hi Everyone...I am trying to figure out how to best finish this part. I built my soffit about 3 inches below my main Heat run. I have 2 spots where the vents to feed the basement heat are just punched into the main trunk line. My question is how do I extend these existing vents to the bottom of the soffit so the actual vent will be on the finished drywall side? The first image gives you a good shot of what I'm working with, the second gives you the perspective of how far below the main run the bottom of the soffit is built. Thanks.

You realize that sound will enter the vent and then that duct?

As Ted alludes to, there will be an issue with sound transmission.

Best bet would be to put some sheet metal over those openings and seal it with RTV and then cut new, round openings in the side of the duct and run flex duct from the round openings down to the openings in your soffit. Make sure you snake the flex duct back and forth so that there are a couple of 90deg bends to help minimize the sound transfer. Tha't just one of many ways to do what you need.

Yes. You'll want to have a soffit act as a muffler for both supply and return. You've got to attenuate the sound in this manner before the new flex duct leaves the theater. PM me if you'd like me to email you some articles / diagrams.

You realize that sound will enter the vent and then that duct?


I do realize that, would it really be any different than it is right now (which Isn't a problem). I haven't and I don't plan to do a whole lot with regards to sound proofing anyway. About the most I was planning was insulation in the ceiling joists. I am not doing the double drywall, green glue, etc. The area will be mostly used for entertaining and family activities, so the need to have a sound proof vault isn't really an issue.

I could run a flex duct for the vent in the picture I sent, but I don't have that option with the other vent...there is no space to tap into the side of the heat run (cold air on one side and beam on the other).

Maybe this question should have been asked in the general theater forum, as I realize now that most will assume this was a dedicated theater where sound proofing is at a premium, where with my area it is not.

Your doing just fine, I looked at your pictures and I would recommend as BudK did, covering, cutting a circle, then using insulated flex ducting and going to the HVAC store and getting the appropriate fittings, then use some metal tape, and maybe go over it once more with high quality duct tape, not the cheap stuff, that will last for years. Maybe even check around locally for an out of work HVAC guy that is looking for some side work that would do it reasonably cheap. Good luck, looks good so far.

I believe that not managing the transfer of sound to the rest of the house is a mistake and it's a mistake that is costly to fix after the fact.

However, if you really don't think you care about it, then cover up the current holes with sheetmetal and get round collars and duct as needed to run the vents out the bottom of the ducts and soffit.

I believe that not managing the transfer of sound to the rest of the house is a mistake and it's a mistake that is costly to fix after the fact.

However, if you really don't think you care about it, then cover up the current holes with sheetmetal and get round collars and duct as needed to run the vents out the bottom of the ducts and soffit.

Well as I stated earlier...I can certainly do the flex duct for the vent in the pictures in my first post, but it won't be possible for the second area...so I'll probably take the advice and do flex duct for the first and go with the box idea for the second vent. The second vent is on the same run, but at the other end of the basement, where much less activity will be taking place anyway. Thanks for the advice.

Although I can only see a partial view of your overall ceiling and soffit construction, I just wanted to point out that you may have wasted 1 1/2 inches of headroom by framing under the beam and ducts.

If those inches are important we can help you.

Here's how I did mine:

http://i625.photobucket.com/albums/tt333/feotto/soffits.jpg

This is like a rectangular take-off but I consider it more of an extension. It has bend tabs so you just mount it in your current hole, and bend the tabs over. You can then just cut or bend the bottom opening to the depth needed. Very easy and no patching/cutting of the trunk involved.

I got mine at Carter Jones Lumber in Solon, OH, and they come in various sizes.

Not to keep beating a dead horse But Floyd's framing design is another example of a wasted 1 1/2 inch of headroom.

Not to keep beating a dead horse But Floyd's framing design is another example of a wasted 1 1/2 inch of headroom.

Yep. Got schooled by Biggy on this very point. I'm so glad now that I did this. The 3" that I would have lost with my framing would reallyhave caused my grief because of the riser, projector mounting point, and headroom between the two.

CJ

Although I can only see a partial view of your overall ceiling and soffit construction, I just wanted to point out that you may have wasted 1 1/2 inches of headroom by framing under the beam and ducts.

If those inches are important we can help you.

I have 9 foot walls...so not a problem.

Here's how I did mine:

http://i625.photobucket.com/albums/tt333/feotto/soffits.jpg

This is like a rectangular take-off but I consider it more of an extension. It has bend tabs so you just mount it in your current hole, and bend the tabs over. You can then just cut or bend the bottom opening to the depth needed. Very easy and no patching/cutting of the trunk involved.

I got mine at Carter Jones Lumber in Solon, OH, and they come in various sizes.

That is what I need.

Not to keep beating a dead horse But Floyd's framing design is another example of a wasted 1 1/2 inch of headroom.

Big, what isn't shown clearly here is that the 2x4's going across the trunk lines are touching the trunk in some areas. The trunks range from 10" to 8" height (I followed the contour where possible) and the beam that I built the wall under is 9-9 1/4", so there was minimal savings to be had here, and it's general living area so the 1/2-3/4" or so I might have saved wasn't important to me.

I am using your suggestion in the HT area though around/along the HVAC trunk. Matter of fact, I'm mounting the 5/8" horizontal OSB/Drywall layer ON TOP of the 2x2 attached along the wall as you suggested. Then covering the "exposed" 2x2 with with crown molding.