Where will the noisy (tv, music) places be?

First floor and basement I’m thinking

If you set the basement up as the main place for loud noises, you can add extra soundproofing to the ceiling. I did NOT do this and was kept up many a night by my teenager and friends doing their best to be quiet while playing video games at 2 AM on weekends. I highly recommend it!!! 😆

We are in a rancher…

Soundproofing comes in different forms. More specific details are useful.

Soundproof: What Works And What Doesn't! - YouTube

The addition of batt insulation is one of the easiest and best bang-for-buck things you can do to help mitigate acoustics. Many builders (except tract) will allow the homeowner to come in and do it themselves.

Soundproofing seems like a great idea, but it isn't easily accomplished by just adding an extra layer of something.

You need to know exactly what product they plan to use and how it will be installed. What are you going to do about sound leaking through outlets and hvac opening and ducts?

If you have specific requirements for acoustics, like a recording studio, a media room, or an unisolated office, then you can get into details of top/bottom of walls, penetrations through walls, ductwork, floor vibrations, window glazing, interior room dampening, etc. But that is typically beyond the scope and need for most homeowners, and would require lots of detailing and money up front prior to construction.

Batt insulation has been shown to provide acoustical reduction, and works well for it's cost and ease of installation.

Batt insulation by itself, whether fibreglass or rockwool, is pretty much irrelevant. But it's cheap and easy to install with huge markups, so is touted by builders.

Constrained-layer drywall, such as Quietrock, or Green Glue between multiple drywall layers is more effective. But it has to be carefully detailed. And since most sound, whether impact or air-borne, comes through flanking pathways, effective soundproofing shouldn't just be an add-on option during the building process.

Here's how adding a layer of OSB and carpet reduces impact sound transmission.

Source

"Batt insulation by itself, whether fibreglass or rockwool, is pretty much irrelevant."

@worthy Not sure where you get that information. Apparently I better go back to all those commercial buildings I spec'd and tell them to remove the duct wrap and mineral wool batts from office partitions, it does nothing. Batt insulation can increase the STC around 5 points.

You provided a link addressing flanking sound transmission. If you notice, all section details already contain thermal or acoustical batt insulation, because it is a starting point standard for mitigating generic through-wall or through-floor sound transmission. If you want to go down a wormhole for a theoretical exercise in applying putty wraps, acoustical sealant, rerouting HVAC returns, and everything else, have at it. You know very well a typical builder will not package any of that for an entire house as an option. They may offer batt insulation between bedrooms and drywall an unfinished basement ceililng.

For a homeowner evaluating costs with no specific needs, batt insulation is perfectly fine, and an efficient use of money with respect to the outcome gained, that does not require any altering of design, further detailing, or coordination of any systems or installation of those. Simply, right after the builder has finished thermal insulating prior to drywall, a homeowner can install batt insulation (even DIY) and receive a benefit that requires little effort and little money that can't be done later.

Thanks everyone for your feedback! Very helpful!

My BF literally wrote the book on acoustics. We chose not to add any extra "acoustic" insulation between walls in our new build.