Correct, I thought about it quite hard and me and my architect decided to make the basement an entertainment and storage center. We removed the bedroom and I’m glad that I did.

So long as you DESIGN the insulation INTO the build you will save money and create a quiet space. I like to see a subfloor built with 2 different layers with a minimum thickness of 3/4" (total thickness).

Stuffing the ceiling of the basement (R19 = thermal insulation...not acoustic insulation) is your best option to reduce noise transfer (impact noise and airborne). I would double stuff the joists with Roxul (cause it's cheap and it has both a fire rating AND an acoustic rating). I would then follow that up with isolation channels AND acoustic drywall (triple the cost of regular ceiling drywall but WELL worth the cost). I would then use the Green Glue isolation tape/patch system as well.

The walls in the basement would have the frames off-set (to reduce noise transfer from room to room = sideways) and insulated as well. Isolation channels are also an EXCELLENT WAY to keep noise from bouncing around in a basement.

And I would WRAP the pipes and the ducts with acoustic wrapping. The amount of noise that travels DOWN the air vents (metal funnel) or down the plumbing pipes (smaller metal funnel = bell) is OUTSTANDING.

The floor is just the START of the noise reduction. Isolation, isolation and then some INSULATION (acoustic not thermal...they are not the same thing). Your architect and builder have to have a solid understanding of acoustic isolation to get a quiet basement. The traditional way of building a home is not enough.

If you throw everything at it, something's bound to work!

If your budget were unlimited, you'd engage a sound control consultant from the start.

In the more practical world, if it's airborne sound from basement to the room above that you're trying to dampen, work on reducing STC Class rating. A second layer of sound damping drywall or conventional drywall with Green Glue is likely your best bet. Avoid penetrations, i.e., potlights. Work on flanking sound paths--that is, nearby partitions and wall and ceiling structures and HVAC that will inevitably short-circuit your best efforts.

One upgrade that builders love to push is stuffing fg or mineral wool in ceilings. Can't hurt. But every technical study shows indiscernible improvement in STC/NIC ratings. For instance, compare the ratings on the top structure and the very similar bottom one except for the added fg.

Source: Kinetic Noise Control

Insulation in the floor-ceiling cavity absorbs a little sound but it doesn't matter what kind it is or how thick it is. Mineral wool insulation is used as fire-safing and is not a substitute for type C or X fire resistant gypsum board and its not fire rated.

No construction material has a "fire rating"; a fire rating is assigned by a testing agency to an assembly that separates spaceslike a wall assembly or a floor-ceiling assembly.

If you are concerned about plumbing noise, you should use cast iron stacks instead of wrapping plastic pipes with expensive acoustic materials.

thank you everyone for the thoughts on the sound isolation. I am well aware of these items as I am big in to home theaters and I have discussed with sound engineers and so forth. I know that what I have done is minimal and may or may not help that much. I know that I am not going to get complete sound isolation

Any thoughts on what I was originally looking for about 3/4 underlayment for hardwood? I know that I said if there is anything that can help with sound that would be great but not a must have

What do you mean by 3/4 underlayment and what are you trying to achieve with it? Are you concerned with foot fall noise bothering the basement occupants?

I'd use the silicone paper product. It should meet your floor warranty requirements and is easy to work with. I'm assuming this is a nailed down floor?

So here' the deal. I've investigated sound transfer because I used to sell cork flooring and underlayment products. Here's what I know:

1. 3/4" wood = 5 dB of noise reduction
2. Regular "pink" R19 insulation = 5-10 dB of insulation (IIC and STC)
3. 6mm of cork (1/4") = 11 dB of impact and airborne (Delta IIC rating) noise reduction
4. 12mm of cork (1/2") = 22 dB of noise reduction (Delta IIC rating)

Consider: a human conversation at 3 ft apart = 60 dB.

Your set-up so far = 5 dB + 5 dB + 10 dB = 20 dB of reduction

Your set-up is considered 'normal' for a family home. Nothing more..nothing less.

If you intend to glue down the hardwood, I would recommend 6mm or 12mm cork for underlayment. The cork can be glued directly to the substrated (plywood) and then the wood floor can be glued to the cork. This is called a double stick.

If you are planning on nailing down, you can sandwich the cork between the 2 layers of subfloor. Do NOT pierce the cork with metal. Metal conducts noise (aka...phone lines used to be made of metal) over distance.

If the entertainment room is in the basement, this is easier. You only have to work with 5 of the 6 sides of the cube. If the entertainment room will be sitting ON the hardwood (as in the theatre room is UPSTAIRS) then this just got more difficult. Now you have to mitigate all 6 sides of the cube to reduce noise transfer from one area to another.

And remember: the low-frequency sound emitted by theatre sound systems can be a BEAST to deal with. This is different from regular airborne transmission. Theatre noise usually incorporates HUGE amounts of volume throughout the entire human acoustic range 20Hz - 20,000Hz.

Regular human vocal sounds (airborne sound) sits in the 300 - 800Hz range. This is what most "regular" insulation deals with. Green Glue, Mass Loaded Vinyl, Rubber and cork all deal with the 500 - 2,000Hz range quite nicely.

The problem comes in with the lower stuff (20-300Hz) that you FEEL in your chest but don't recognise as "hearing" it. These deep vibration noises are often used in the movie industry to bring about the unnerving sensation of "tension" or "being watched" or any other form of sensation common with thrillers, suspense or horror movies.

The UPPER range (the extreme range of violins, piccolos, cymbals like high-hats, etc) are also a problem. Not many products on the market can deal with high pitched noises (4,000Hz = most annoying noise to the human ear = finger nails on a chalk board = highest note in the piccolo's range).

These "bothersome" sounds are rarely found in the day to day running of a household. Talking on the phone, cooking a meal, typing on a keyboard, walking down the stairs are all noises that are either intermittent (foot steps) or of such low volume (not very loud) that normal insulation practices are considered adequate.

The problems are magnified when these problem noises are PROLONGED or of such VOLUME that they overwhelm the acoustic system....as would be the norm for a home theatre or home entertainment system.

In otherwords it is SOOOO much cheaper to assume your theatre room is GOING TO BE A NUISANCE and mitigate it to the point of financial hardship. Do everything you can think of to keep the room as isolated as possible.

How much irritation are you and your family willing to put up with? If your love of a theatre system out-weighs your irritation, then you are just fine. If you WANT more insulation and you EXPECT more noise control, your set-up won't do a thing towards what you want or expect.

Thanks for the feedback. I apologize on my typo of 3/4 underpayment. I meant that I am going to have 3/4 hardwood and looking for the underlayment for the hardwood. I am not expecting major sound isolation from what would be a very basic and non dedicated theatre space in the basement.

I’m debating do I get the typical thin black moisture barrier that goes between the sub floor and the hardwood or is there something that is still cost affective and provides a little help with foot traffic?

I know it is not going to be perfect as to get it there it cost a lot of money between the multiple layers, space and other things such as green glue.

Hopefully this helps a little

There are underlayments (underpads) such as Quietwalk that allow hardwoods to be nailed down over top. The Quietwalk is one of the few rigid-flooring upderpads that can be PIERCED. It maintains most of it's noise abatement qualities even after being punched through with thousands of nails.

It is more per square foot than the kraft paper...but certainly WELL WORTH the extra money. It is something that will go A LONG WAY with a little bit more investment.

Thanks SJ McCarthy. This is what I was looking for. Does this product really help with dampening sounds?

Quietwalk, as its own website claims, is aimed at reducing floor-to-ceiling noise, not the reverse, which is what the OP says is the issue.

Furthermore, the manufacturer says it is designed for floating laminate or engineered floors, not the "3/4" natural hardwood" the OP says he is intending to install.

"Quietwalk plus" is design for all three types of installation: nail, float or glued. Design for solid and engineered.

I am also searching for an option for 3/4 inch thick 2.25 inch wide solid hardwood nail down installation with plywood subfloor over a conditioned basement (there is a small area that is over an unconditioned crawl space). We are managing the sound transmission UP from the basement with insulation in the ceiling and double drywall with green glue.

Now I need to figure out an underlayment for the flooring upstairs to do the following: reduce impact sound DOWN to basement, provide some cushion under flooring especially in the kitchen, prevent squeaking floors. Our builder was just going to use felt paper but he admits that will only help with squeaking so I have to source a product. It has been a rabbit hole!

I do not want to glue down the floors, I want to nail down. I am not looking for a perfect sound proofing, just dampening so I am not worried about penetrating with nails. Some of the options say you can use for nail down, but not on boards less than 3/4 inch thick or less than 3 inch wide so that won't work for ours. With a google search it just keeps leading me back to the same products.

So Chad Bertke, what did you decide? Does anyone else have any other options??

Quietwalk has an underlayment designed for nail-down hardwood floors. That means it can be pierced with nails without any issue. Quietwalk is one of the only underlayments that I believe is worth the price. The other is 6mm cork underlay (or 12mm if you can find it) for the price you pay.

You do not want a glue down hardwood so cork is out (it is not allowed to be pierced by nails). Go to the Quietwalk website and find the one designed for nail-down-hardwood.

Thanks SJ, I see you are very helpful with many folks asking similar questions, that is very generous of you. It seems unusual to me that there is no other option for nail down hardwood underlayment with some sound dampening besides quiet walk...i tend to be a little nervous when I don't see any competition. But that is just me.

@ S F...You are very welcome. I'm a helper, not a salesperson (I love selling things...but I don't like to be called a 'salesperson'). I'm glad I could help.

I understand the 'lack of competition'. I know. The building industry is expensive for companies to get involved in. If they make a claim (like noise reduction or fire rating) they have to back it up with numbers.

When my company wanted new acoustic ratings for their 12mm cork underlay, they had to pay $10,000 for a SINGLE test. It was a very very very basic test (Delta ratings test = 6" concrete slab + 12mm cork underlay + 11m cork floating floor on top). If we wanted to BEEF UP the numbers (which most of these companies want to do...ahem) we would have had to pay another $15-$20K (more than double the basic costs). If we had wanted to add a 'burn test' to our acoustic test, we would have had to spend another $15K to find out how our floors burned (ignition point, flame spread, off-gassing, etc).

These 'testing' costs drive the industry to create bigger and better items. It is also a limiting factor for the smaller innovators. If one or two companies go a head and spend money on these items (and create a great product that does NOT have to be 'beefed up' in the laboratory) then that's about all the industry needs.

Many companies try to buy 'good' numbers...but ultimately they fail because the end user does NOT get the results they had been 'sold on'. That's where word of mouth begins to bite back. Those companies eventually end up folding OR they drop the product and acknowledge the products they make is NOT 'all that'.

I've looked at the numbers for QuietWalk Plus and have been impressed (I know what they used in their testing procedures = they did NOT try to 'buy' good numbers). As a cork flooring professional (with a strong understanding of acoustics and how bad products can carry 'good numbers') I would not hesitate to use QuietWalk Plus under a nail-down hardwood. It is as good as 6mm cork underlay (but not quite as good as 12mm cork underlay).

There are VERY FEW products that can compete with 6mm cork underlay. QuietWalk Plus is one of them.