Basement Drum Room In Townhouse

[Gregwor]

I understand the first part, the baffles too long, but I'm not sure about the cross sectional part. Is that the area where the baffles end? If we cut down the baffles will that address both issues?

You can figure out your cross sectional area by multiplying the width by the height in your silencer box air path. Remember, you're going to lose 1" due to duct liner all around it! So, basically take off 2" from each dimension. Also, you need to make sure that your silencer box cross sectional area is at least twice that of the duct feeding it.

So, around the ends of the baffles, it appears that your cross sectional area is really squished down to nothing. If you cut the baffles ends shorter, that should open up that path. I'm afraid though because if you're asking about the cross sectional area now, how did you design your silencer boxes in the first place?

Regarding the Owens Corning, I'm only seeing a couple of sausage shapes packages on ebay, everyone else wants a quote request. I don't think I need that much. If I cannot get this, is there another product that would come close?

Ebay is probably very expensive. Especially since the product is large. Maybe call some local HVAC companies and ask if they have any duct liner they'd sell you. You could probably buy a roll from a wholesale supplier, but you'll probably end up with a full roll. This might be okay as you can use it in a few spots for treatment, but there are very few areas of your studio that only require 1" thick insulation!

Unfortunately you cannot use any regular insulation for this task. And if you don't have duct liner, your silencer boxes will not work very well. Period.

Greg

[merpmerp]

you need to make sure that your silencer box cross sectional area is at least twice that of the duct feeding it.

So, it the duct feeding it is 6", that area above the baffle needs to be 12"? Is there a ratio, baffle to cross sectional area that I should be trying to achieve?

how did you design your silencer boxes in the first place

We used the diagram in the Gervais book as a guide. I do remember the contractor saying something didn't add up correctly.

Ebay is probably very expensive. Especially since the product is large. Maybe call some local HVAC companies and ask if they have any duct liner they'd sell you.

OK, so it doesn't necessarily need to be Owens Corning, but it should be 1" duct liner that I'm looking for?

Thank you

[Soundman2020]

So, it the duct feeding it is 6", that area above the baffle needs to be 12"? Is there a ratio, baffle to cross sectional area that I should be trying to achieve?

Careful with that! A 6" duct refers to the diameter of the duct: You need to use the cross sectional AREA of the duct, not the diameter, radius, or circumference. The area of a 6" round duct is about 28 in2. So you would need a cross sectional area of AT LEAST 56 in2 inside your silencer, AFTER accounting for the thickness of the duct liner. So the internal measurements of the box would need to be at least 7" x 8", plus the 2" of duct liner, therefore 9" x 10".

Is there a ratio, baffle to cross sectional area that I should be trying to achieve?

Try to keep the baffles large enough to cover at least half the width of the box interior, plus the thickness of the duct liner, and still leave the correct cross sectional area beyond the end of the baffle to the opposite wall.

OK, so it doesn't necessarily need to be Owens Corning, but it should be 1" duct liner that I'm looking for?

Correct. Any good quality interior duct liner will work. But do make sure that it is INTERIOR duct liner, ie, the type meant for use inside the duct! There are also some other types of duct liner meant to be used on the OUTSIDE of the duct: That's not what you want.

- Stuart .

[Gregwor]

I drew this up last night. Hopefully it will help you out:

Gregwor's Silencer Box.png

Greg

[merpmerp]

Cool! Great timing, thanks!

[merpmerp]

Hello, it's been a while but I'm ready to get back to working on the room.

So far the ceiling it done and I need to start on the walls.

There is one cement wall, the wall between my neighbor and myself. The framing on the wall is out about two inches from the cement wall. There was John Manville insulation from the builder that I took down to put up Roxul Safe n Sound (rockwool).

I'm not sure if I should put it just in the framing, or, against the cement wall? If I put it against the cement wall, I have room to add the John Manville insulation back between the studs.

Should there be a space though between the framing and the cement wall if I just put the roxul safe n sound in the framint?

The wall is pretty dry, no sign of moisture. I'm wondering if that would change if I had it packed completely with the roxul safe n sound against the cement and the John Manville in front of it in the framing.

Thanks for your help!

cement wall 3.jpg

cement wall 2.jpg

cement wall 1.jpg

[John Sayers]

Just use the rockwool between the studs off the cement wall and keep the Manville to use later in the design.
cheers
john

[merpmerp]

Just use the rockwool between the studs off the cement wall and keep the Manville to use later in the design.
cheers
john

OK, thank you!

[merpmerp]

I understand the first part, the baffles too long, but I'm not sure about the cross sectional part. Is that the area where the baffles end? If we cut down the baffles will that address both issues?

You can figure out your cross sectional area by multiplying the width by the height in your silencer box air path. Remember, you're going to lose 1" due to duct liner all around it! So, basically take off 2" from each dimension. Also, you need to make sure that your silencer box cross sectional area is at least twice that of the duct feeding it.
Greg

I'm still a little confused on the area. The length doesn't factor? OK, the width x height minus the baffles, or just width x height?

Also, would this work for the interior if I were to glue two 1/2 inch pieces together:

https://standardandchan.com/product/joh ... gLcSvD_BwE

Thank you for your help.

[merpmerp]

I'm really hoping someone can answer because I am at a standstill right now.

OK, the interior of my box is 16" wide x 10" high. If I add 1" all around, I guess that becomes 14 x 10 = 140.

Before we started working on the ceiling we removed the 6" duct work that was installed between the joists for that room. There was no return in that room.

So, if I use 6" duct work (I'm referring to the hose), that should be fine based on the area of the box, yes?

How do you refer to the name of the holes in the box? What dimensions should they be for incoming and outgoing.

Also, I was planning on adding a 6" hose to the HVAC to replace the one that was removed and using that to feed the room from the storage area adjacent to it. However, for the past couple of weeks with mild temperatures, we haven't had the a/c or the heat on. So, there would be nothing coming into the room in that case.

Would I be better off making what I think is called a dead vent and just bringing in air from the storage room into the drum room?

Also, as there was no return to begin with, I was just going to have another box in the sump pump room on the other side of the drum room (it goes storage room, drum room, sump pump room) which has an open space between the basement and 1st floor for the air to go into.

I'm not sure whether to have two boxes or four boxes but, if I have four boxes, how do I connect them on the inside of the room and outside of the room, and if I have just the two boxes on the outside, what do I just to connect the box on the outside to the register on the inside?

Thank you for all of your help with this. I know it's a lot of questions but it's what's keeping me from moving forward right now.

[merpmerp]

I drew this up last night. Hopefully it will help you out:

Gregwor's Silencer Box.png

Greg

If my "Y" is 16, then X= (16-7)/2= 4.5. On the right side of the box, should that be (2x)+5, not (2x)+3? 2(4.5)+3= 12 but I'm only losing 2" off of the 16 with the duct liner. Wouldn't that be 14?

Thank you

[Gregwor]

Sorry to leave you hanging man. I've been swamped and unable to visit the forum everyday. Without Stuart here helping answer questions, it's pretty tough to get to everyone in a timely manner.

If my "Y" is 16, then X= (16-7)/2= 4.5. On the right side of the box, should that be (2x)+5, not (2x)+3? 2(4.5)+3= 12 but I'm only losing 2" off of the 16 with the duct liner. Wouldn't that be 14?

No, it would be (2*4.5)+3 which would be 9+3 = 12". This would leave 4" from your total width of 16". Those 4" come from 1" of MDF and 1" of duct liner on each side of the silencer box.

OK, the interior of my box is 16" wide x 10" high. If I add 1" all around, I guess that becomes 14 x 10 = 140.

No. It would end up being 14 x 8 because the top and bottom of your silencer needs ducts liner on it as well.

So, if I use 6" duct work (I'm referring to the hose), that should be fine based on the area of the box, yes?

You need the interior cross sectional area of your box to be at LEAST twice that of the duct work feeding the box. So, if you need to, you could make the entrance to your box smaller in order to introduce the impedance change. Just be aware that this will introduce a pressure drop! That's why it's the dream to have nice big silencer boxes (because they offer higher insertion loss and less pressure drop).

How do you refer to the name of the holes in the box? What dimensions should they be for incoming and outgoing.

Inlets/Outlets but these are created using "sleeves".

Would I be better off making what I think is called a dead vent and just bringing in air from the storage room into the drum room?

I've seen this done quite a bit. I don't fully endorse it as fresh air from outside as well as dumping stale air outside is ideal. But if thought through properly, you can have a working system pulling and dumping within your dwelling. There are rules about dumping stale air or pulling stale air from rooms in your home though.

I'm not sure whether to have two boxes or four boxes but, if I have four boxes, how do I connect them on the inside of the room and outside of the room, and if I have just the two boxes on the outside, what do I just to connect the box on the outside to the register on the inside?

Your "sleeves" on your boxes must penetrate your leaf sheathing. That is what allows the box to maintain it's surface density and ultimately it's isolation. Typically people just screw a register cover onto the end of the sleeve. To connect your inner and outer leaf sleeves you must use something flexible. The cheapest and easiest route is to use flex duct but often there isn't room for that in joists. Check out DuroDyne flexible duct connectors as an example of something to use that isn't flex duct.

Greg

[merpmerp]

Greg,
Thank you, for that information. I had to take a break for a couple months due to some issues, but I want to get back to this.

I don't think I gave you the correct dimensions of my box.

It is 36" x 18" x 12" on the outside. The inside is 34.5" x 16.5 x 10.75.

The baffles are 12" and the space in between the baffles and the side of the box is 4.5".

Based on your formula, I think I should cut the baffles down to 9" or 9.5".

Is that correct?

Also, should the walls be completed first and then the boxes installed or, the boxes installed first?

It seems like it would be easier to put up the sheet rock then to cut the sheet rock around where the boxes are installed.

Thank you,

Mark

[Gregwor]

Based on your formula, I think I should cut the baffles down to 9" or 9.5".

Is that correct?

If that's what the picture says, then it must be right ---- or I completely screwed it up hahaha

Also, should the walls be completed first and then the boxes installed or, the boxes installed first?

Great question. This is something I'm constantly considering when designing. There is no real answer because every build is different. Basically, as long as you can get everything installed, do it whatever way you find possible or easiest. I really question how I'm going to get the HVAC done in my personal build. It's going to be so tight and crazy

Greg

[merpmerp]

Just wanted to give an update here as well as thank Stuart and Greg for all of their help.

The room is done! It might not be 100% (I'll get to that) but it works for what I need it to do.

I last left off with the baffle box question and I think it was the cleats and sheet rock between the joists that were mentioned last.

Well we did the ceiling first.

Ceiling 1.jpg

ceiling 2.jpg

Packed it with plenty of Roxul Safe N Sound, then added two layers of sheet rock with green glue in between and that was installed on the channel with the isolation clips. I helped the contractor here.
I wanted to get lift for the sheet rock, but he didn't think we needed it. Needless to say, after the ceiling was done he texted me a picture of him in an ambulance because of his back. He was finished as a contractor.

After a few months, I found someone that does theater rooms to start work again. His nickname is "The Wallologist" and we were pretty much on the same page as to what needed to be done.

So, we did covered the outlets with putty and did the isolation clips, hat channel, and two layers of sheet rock with green glue in between. On the other side of the three walls (not the cement with the neighbor's townhome on the other side) we did two layers of 5/8 sheet rock with green glue in between.

You can see the spacing in between from the isolation clips in a couple of pics:

Wall 1.jpg

I needed two doors, one for the basement area and one for the sump pump room. I got solid core exterior doors with the weather stripping all around and the metal plate at the bottom (forgot what that is called). The doors are the weakest link. I know that because I went to the side of room in the storage area while I had the amp inside cranking at about 110 db. The sound where I was standing was about 60db and I could tell it wasn't coming from the wall I was right next to, but flanking from the door to the basement from the drum room and then coming into the storage area.

This was several months ago. I was going to add mass loaded vinyl to the doors with 3/4 mdf and then sheet rock with green glue in between. While I was waiting for the mlv to come, the Wallologist took on another job. It kept him active for a while. In the meantime, I played the drums. My wife was almost directly above and didn't need to turn up the television if she was watching while I played. I didn't hear anything from my neighbor.

A couple of months went by and since there were no complaints I decided, OK, just the mlv and mdf, no sheet rock. The Wallologist was still busy. Now, it's been months, my wife has no problem, and I'm not even sure if my neighbor knows I play the drums anymore!

I forgot to mention, I've been playing the acoustics. I haven't touched the electronics in months, even poached a couple of cymbal stands from it.

Another thing, and Greg and Stuart will probably hate this, but I have no ventilation. I still have the one baffle box that needs to be corrected but it is in the sump pump room just holding things on top of it. The room is always in the low 60's F. It's sealed up pretty tight so I got myself a CO2 detector. I have it set to go off at 2000 ppm. That is usually after about an hour, hour and a half and then I just open the door and go get myself a drink. I don't play for much longer than that anyway, so it has been fine. When it comes time to sell, we'll just reinstall the a/c vent that was removed.

I have eight acoustic panels for sound treatment along with about 50 of the foam type wedges. The acoustic panels (not cheap) really do a great job.

Overall, I'm very happy with the room and the fact that I get to play my acoustics again without bothering anyone. Thanks again for all of the valuable information on the site!

( I wanted to space the words and pics and have the finished product at the end, but was not able to do that, but you can tells what's finished and what's not)