Thoughts on finishing a basement and leaving every X 16 on center open with acoustic material...

[jinjuku]

I'm putting together a budget for finishing a basement space and was thinking about floor to ceiling 1st reflection wall mount. What if I just fill in the 16" on center wall cavity with Acoustic batting and then trim around with moulding and with a AT transparent fabric making it wall flush?

Just looking for creative thoughts.

 

[Eppie]

I'm putting together a budget for finishing a basement space and was thinking about floor to ceiling 1st reflection wall mount. What if I just fill in the 16" on center wall cavity with Acoustic batting and then trim around with moulding and with a AT transparent fabric making it wall flush?

Just looking for creative thoughts.

I look at the practicality first. Are there any outside walls or are they all interior walls? Building codes here require that a continuous plastic vapour barrier cover the insulation on exterior walls to control moisture. If that is not a requirement, next thing to consider is sound transmission to adjacent rooms. If that is not an concern, then I would ensure that the fabric is strong enough so that if someone leans on the fabric it will not tear. In theory it should work as well as a wall mounted panel but be flush with the wall.

 

[jinjuku]

One wall is 27' and the outside wall. I have 4 mil, 10' wide plastic vapor barrier for that with pressure treated bottom plate. So plastic will wrap under the bottom plate also. Then dimple under layment with osb on top for the sub floor.

 

[Eppie]

One wall is 27' and the outside wall. I have 4 mil, 10' wide plastic vapor barrier for that with pressure treated bottom plate. So plastic will wrap under the bottom plate also. Then dimple under layment with osb on top for the sub floor.

If the floor is concrete you definitely do not want the wood in contact with the floor, even if it is pressure treated. Builders here use a gasket material for separation. If you wrap the vapour barrier under the bottom plate, I recommend not wrapping it up the rear side. If you get any water intrusion, the plastic will form a channel that holds water, so just wrap the front and bottom to allow water run off. A good underlayment is great for both moisture control and to act as a thermal break. I used a tongue and groove 2 foot x 2 foot OSB panel with corrugated plastic channels underneath (DRICORE) for my subfloor and it was a great investment. The floor is much warmer in the winter now. DRICORE can get expensive for a large room so the OSB and underlayment can be much more cost effective. I've seen the dimple barriers but also DuroFoam boards which acts as a thermal break. Depends on local building codes. Not that you asked for construction advice. There is lots of good content on Youtube these days for almost any kind of job but the flush acoustic panel is one I have not seen before.

 

[jinjuku]

On the ground contact I was thinking about foam sill plate. The stuff that comes on a roll.

Why doesn't the vapor barrier go next to the wall. It's wall, insulation, vapor barrier, drywall? What happens to the damp insulation and untreated 2x4?

 

[TLS Guy]

On the ground contact I was thinking about foam sill plate. The stuff that comes on a roll.

Why doesn't the vapor barrier go next to the wall. It's wall, insulation, vapor barrier, drywall? What happens to the damp insulation and untreated 2x4?

If you have a poured or block basement, then you need to prevent water egress. Concrete is porous. It is essential to seal the concrete. Then put up the stud frame. Fiber glass insulation is best, placed between the 2 X 4s. Then you place the polythene sheeting over that stapling it to the 2 X 4s. Then you are ready to place the drywall.

Basement floors are a problem, and a source of moisture egress.

The best options are tiling, but not for an AV room. Unfortunately you can not use wool which is best acoustically.
Do not use a fibrous underlay. I recommend a polyurethane underlay, and a synthetic carpet.

Since this is an AV room, you want to put insulation in the ceiling, not only for noise control, which it does somewhat, but for acoustic reasons. Since this is an AV room you should put insulation behind all interior walls.

Run in wall conduit to all locations. Do not put any cables behind any wall or barrier not in conduit. This is an absolute rule.

Another tip is to run AC mains for TV and any sub, back to the equipment location and ground it at one location. This prevents ground loops. Pay real attention to your grounding plan. This pays huge dividends. The whole design should concentrate on avoiding ANY possibility of a voltage between grounds. This includes paying great attention to cable and ethernet installation, which are a potent source of ground loops.

Make sure there is insulation behind all walls and in the ceiling. Then with an adsorbent carpeting no other acoustic treatment should be necessary. Insulation behind the dry wall is all I have found to be necessary. Since this is existing construction, I doubt you are in a position to design with optimal room dimension ratios, but if you are, then do.

In my experience if you follow those rules and have good speakers with uniform dispersion, no other acoustic treatments will be required.

Here is a link to my room build, which you may or may not find helpful.

Here are some more pictures.

I have found though, basements to be a problem. I don't think there is a fool proof way of staying out of trouble.

I have owned four houses with basements, two of which I built. One of those four only had a very partial basement, and yet I did have problems with all of them from time to time. I don't think these is a guaranteed way of avoiding every problem with basements. That is why in this our last house, I made darn sure it did NOT have a basement.

 

[highfigh]

I'm putting together a budget for finishing a basement space and was thinking about floor to ceiling 1st reflection wall mount. What if I just fill in the 16" on center wall cavity with Acoustic batting and then trim around with moulding and with a AT transparent fabric making it wall flush?

Just looking for creative thoughts.

If it's inhabited space, the code will usually require some kind of material over it. Make sure the acoustic absorption materials won't shed fibers that could be inhaled, causing respiratory problems.

You shouldn't need floor to ceiling absorption- use the acoustics sites to calculate the amount (percentage) of surface area that needs to be absorptive/reflective/diffusive to get it right, not just using a 'scorched earth' method.

I just searched using 'How do I determine the amount of sound absorption and reflection needed in a home theater?' and the results show many links that aren't trying to sell something.

 

[highfigh]

If you have a poured or block basement, then you need to prevent water egress. Concrete is porous. It is essential to seal the concrete. Then put up the stud frame. Fiber glass insulation is best, placed between the 2 X 4s. Then you place the polythene sheeting over that stapling it to the 2 X 4s. Then you are ready to place the drywall.

Basement floors are a problem, and a source of moisture egress.

The best options are tiling, but not for an AV room. Unfortunately you can not use wool which is best acoustically.
Do not use a fibrous underlay. I recommend a polyurethane underlay, and a synthetic carpet.

Since this is an AV room, you want to put insulation in the ceiling, not only for noise control, which it does somewhat, but for acoustic reasons. Since this is an AV room you should put insulation behind all interior walls.

Run in wall conduit to all locations. Do not put any cables behind any wall or barrier not in conduit. This is an absolute rule.

Another tip is to run AC mains for TV and any sub, back to the equipment location and ground it at one location. This prevents ground loops. Pay real attention to your grounding plan. This pays huge dividends. The whole design should concentrate on avoiding ANY possibility of a voltage between grounds. This includes paying great attention to cable and ethernet installation, which are a potent source of ground loops.

Make sure there is insulation behind all walls and in the ceiling. Then with an adsorbent carpeting no other acoustic treatment should be necessary. Insulation behind the dry wall is all I have found to be necessary. Since this is existing construction, I doubt you are in a position to design with optimal room dimension ratios, but if you are, then do.

In my experience if you follow those rules and have good speakers with uniform dispersion, no other acoustic treatments will be required.

Here is a link to my room build, which you may or may not find helpful.

Here are some more pictures.

I have found though, basements to be a problem. I don't think there is a fool proof way of staying out of trouble.

I have owned four houses with basements, two of which I built. One of those four only had a very partial basement, and yet I did have problems with all of them from time to time. I don't think these is a guaranteed way of avoiding every problem with basements. That is why in this our last house, I made darn sure it did NOT have a basement.

A small point- he doesn't want water ingress. Egress is when someone or something leaves.

 

[jinjuku]

Another tip is to run AC mains for TV and any sub, back to the equipment location and ground it at one location. This prevents ground loops. Pay real attention to your grounding plan. This pays huge dividends. The whole design should concentrate on avoiding ANY possibility of a voltage between grounds. This includes paying great attention to cable and ethernet installation, which are a potent source of ground loops.

I'm running a balanced pre-pro

 

[highfigh]

I'm running a balanced pre-pro

That doesn't mean ground loops are impossible.

NEC Article 800-

https://www.ecmag.com/magazine/articles/article-detail/codes-standards-communications-systems-grounding-rules-article-800-provides-specific

Article 725/800 clarification-

Clarifying NEC Articles 725 and 800 | Consulting - Specifying Engineer

Learning objectives Understand NEC Articles 725 and 800, and how they affect network cabling for electrical engineers. Determine which Article to start | Consulting - Specifying Engineer

www.csemag.com

 

[jinjuku]

That doesn't mean ground loops are impossible.

NEC Article 800-

https://www.ecmag.com/magazine/articles/article-detail/codes-standards-communications-systems-grounding-rules-article-800-provides-specific

Article 725/800 clarification-

Clarifying NEC Articles 725 and 800 | Consulting - Specifying Engineer

Learning objectives Understand NEC Articles 725 and 800, and how they affect network cabling for electrical engineers. Determine which Article to start | Consulting - Specifying Engineer

www.csemag.com

I know that. I have a Denon 3308CI and an Onkyo DHC 80.3 with balanced outputs. Every single time I've ever had mains hum with the Denon, I put in the Onkyo and it all goes away.

 

[Eppie]

On the ground contact I was thinking about foam sill plate. The stuff that comes on a roll.

Why doesn't the vapor barrier go next to the wall. It's wall, insulation, vapor barrier, drywall? What happens to the damp insulation and untreated 2x4?

Foam for sill plates should be fine as they typically sit on concrete as well. It just needs to be closed cell foam so that moisture can not penetrate it.

The vapour barrier always goes on the warm side to prevent condensation. If you were to put vapour barrier against the wall, then your acoustic insulation and then fabric, the warm moist air from the room would go through the insulation and condense on the cold vapour barrier. Damp insulation on wood can lead to mold which is a serious health hazard.

Highfigh makes a good point about building codes. Codes will likely require that there be insulation, vapour barrier and drywall on outer walls if it is a finished space, so sound absorption material between the studs covered in fabric will likely not meet code on outer walls. I think you're best to follow standard building practices and follow TLS_Guy's and Highfigh's advice on sound treatment. If the room is carpeted with big furniture you may find that insulation inside the walls and ceiling is enough. If the room is too lively, you can always add treatments per the method mention by Highfigh.

 

[TLS Guy]

Foam for sill plates should be fine as they typically sit on concrete as well. It just needs to be closed cell foam so that moisture can not penetrate it.

The vapour barrier always goes on the warm side to prevent condensation. If you were to put vapour barrier against the wall, then your acoustic insulation and then fabric, the warm moist air from the room would go through the insulation and condense on the cold vapour barrier. Damp insulation on wood can lead to mold which is a serious health hazard.

Highfigh makes a good point about building codes. Codes will likely require that there be insulation, vapour barrier and drywall on outer walls if it is a finished space, so sound absorption material between the studs covered in fabric will likely not meet code on outer walls. I think you're best to follow standard building practices and follow TLS_Guy's and Highfigh's advice on sound treatment. If the room is carpeted with big furniture you may find that insulation inside the walls and ceiling is enough. If the room is too lively, you can always add treatments per the method mention by Highfigh.

You don't want to make a room too dead. If you need to make a room dead then your speakers are just no good.
When speakers are overly fussy about rooms and placement that is a tip off to speaker problems.
Your point about codes is important. The vapor barrier must be done right and you must not breach fire wall codes.

 

[highfigh]

I know that. I have a Denon 3308CI and an Onkyo DHC 80.3 with balanced outputs. Every single time I've ever had mains hum with the Denon, I put in the Onkyo and it all goes away.

Does one of them have a grounded power cord?

 

[highfigh]

If you have a poured or block basement, then you need to prevent water egress. Concrete is porous. It is essential to seal the concrete. Then put up the stud frame. Fiber glass insulation is best, placed between the 2 X 4s. Then you place the polythene sheeting over that stapling it to the 2 X 4s. Then you are ready to place the drywall.

Basement floors are a problem, and a source of moisture egress.

The best options are tiling, but not for an AV room. Unfortunately you can not use wool which is best acoustically.
Do not use a fibrous underlay. I recommend a polyurethane underlay, and a synthetic carpet.

Since this is an AV room, you want to put insulation in the ceiling, not only for noise control, which it does somewhat, but for acoustic reasons. Since this is an AV room you should put insulation behind all interior walls.

Run in wall conduit to all locations. Do not put any cables behind any wall or barrier not in conduit. This is an absolute rule.

Another tip is to run AC mains for TV and any sub, back to the equipment location and ground it at one location. This prevents ground loops. Pay real attention to your grounding plan. This pays huge dividends. The whole design should concentrate on avoiding ANY possibility of a voltage between grounds. This includes paying great attention to cable and ethernet installation, which are a potent source of ground loops.

Make sure there is insulation behind all walls and in the ceiling. Then with an adsorbent carpeting no other acoustic treatment should be necessary. Insulation behind the dry wall is all I have found to be necessary. Since this is existing construction, I doubt you are in a position to design with optimal room dimension ratios, but if you are, then do.

In my experience if you follow those rules and have good speakers with uniform dispersion, no other acoustic treatments will be required.

Here is a link to my room build, which you may or may not find helpful.

Here are some more pictures.

I have found though, basements to be a problem. I don't think there is a fool proof way of staying out of trouble.

I have owned four houses with basements, two of which I built. One of those four only had a very partial basement, and yet I did have problems with all of them from time to time. I don't think these is a guaranteed way of avoiding every problem with basements. That is why in this our last house, I made darn sure it did NOT have a basement.

Sounds like the drainage around the basement wasn't able to divert water well enough. Did the basement have a drain tile along the highest sides, sloped in a way that allows the water to leave the area and flow to low ground? Did the foundation contractor parge the concrete walls? Did they add some other material that allowed the water to reach the drain tile around the perimiter? Was the drain tile outside of the footing, or inside, under the floor and leading to a sump pump?

Many methods can prevent water problems but they need to be able to work in unison. As long as there's no way to have positive water pressure outside of the foundation, water won't enter and with a membrane that won't let water pass through, capillary action won't be a problem, either. At that point, only interior condensation will make the concrete wet and that's easy enough to address.

 

[TLS Guy]

Sounds like the drainage around the basement wasn't able to divert water well enough. Did the basement have a drain tile along the highest sides, sloped in a way that allows the water to leave the area and flow to low ground? Did the foundation contractor parge the concrete walls? Did they add some other material that allowed the water to reach the drain tile around the perimiter? Was the drain tile outside of the footing, or inside, under the floor and leading to a sump pump?

Many methods can prevent water problems but they need to be able to work in unison. As long as there's no way to have positive water pressure outside of the foundation, water won't enter and with a membrane that won't let water pass through, capillary action won't be a problem, either. At that point, only interior condensation will make the concrete wet and that's easy enough to address.

Everything was done properly, with drain tile and sumps. The problem is that this whole region has huge Geotech issues. Ground water is high in many areas, including our current location, which is why I nixed a basement.
The Red River Valley is particularly bad, and basement issues are the rule, especially in Spring. At the Lake there were springs all over the place, including a few feet from the house. The reason being that we were right over the junction of the Wadena and Superior plates. I only had a few feet of basement on that house at the back, and still had to take corrective action.

So I got to to know the staff from Geological Survey on a first name basis.

 

[highfigh]

Returning to the original post, one place to start is by finding the room modes and using that to correct some of the problems-

amroc - THE Room Mode Calculator

HTML5 room mode calculator. Read and hear the tune of axial, tangential and oblique modes. Scientific sources included.

amcoustics.com

 

[jinjuku]

Does one of them have a grounded power cord?

Both will be deprecated as I'm moving onto a 7.2.4 Atmos setup. Just need to figure out if I'm going to attempt the Emotiva MR1 and reduce my amplifier stack or Marantz 7706 used/refurbished.

Either way my sub's are using a Behringer DSP amp with XLR.

It seems like Emotiva is questionable now days(?) I noticed on the MR1 that they custom heat shrink wrap the capacitors. Like maybe they don't want people knowing the thermal ratings.

 

[highfigh]

Both will be deprecated as I'm moving onto a 7.2.4 Atmos setup. Just need to figure out if I'm going to attempt the Emotiva MR1 and reduce my amplifier stack or Marantz 7706 used/refurbished.

Either way my sub's are using a Behringer DSP amp with XLR.

It seems like Emotiva is questionable now days(?) I noticed on the MR1 that they custom heat shrink wrap the capacitors. Like maybe they don't want people knowing the thermal ratings.

That's something I would call them on, because it presents a safety risk (depending on the materials inside, which can smoke during failure and cause health problems).

If the heat shrink is over the original, it may be for preventing overheat and in that case, I would say they should have laid out the power supply differently- are the caps near the heat sinks?

 

[jinjuku]

Found a Marantz AV7706 for $1600 so that is completed line item.