Help Building ADR/Foley Room

[stashmanguitar]

I'm looking to build a room to record ADR & Foley but need a little bit of advice on getting there. I would need the room to be as dead as possible as I will be using very sensitive mics and pres at very high levels to be able to record the smallest of sounds. This room would be in my basement so I would also need help in figuring out how to isolate sounds from the house being audible in the room and vice versa (if possible).

The usable area's dimensions are 38' x 12' x 7'. I plan on dividing the space in half into a recording area and control room. The ceiling and walls are drywalled and the floor is currently linoleum tile on concrete.

I've already found a bunch of useful information on building mixing rooms searching on the forum, but I can't seem to find anything on rooms for recording sound effects. All advice, if any, would be extremely helpful.

 

[RICK FITZPATRICK]

This room would be in my basement so I would also need help in figuring out how to isolate sounds from the house being audible in the room and vice versa (if possible).

First you need to define your required isolation...ie...what is the LOUDEST sound that the room must be isolated from and at what frequency.

For instance, if LOUDEST sound of the existing environmental noise floor is 55db at 40hz(perhaps road rumble)..and you do NOT want this to transmit into your space, then you must build assemblys that have a TRANSMISSION LOSS equal to or above this sound level at that frequency. Not an easy nor cheap task. Especially if you are mic'ing VERY LOW intensity sounds. This infers your mics pres will be turned up and will pic up even very low intensity sounds that transmit into the room.


For professionals who must undertake this sort of task, the very first thing they do is measure the existing transmission loss of the building envelope. They do this by measuring, with an SPL meter, the existing noise floor, outside the building, on all sides(usually about a meter away or so), inside the building in various rooms adjacent to the target room, and in the target room, at various times of the day/night, to get an idea of how well the existing building assemblies perform in terms of TL.

They do this by comparing the measured external noise floor compared to the internal
noise floor in db, and frequency. In some instances, these measurments are critical to the success of the target TL that the new construction must meet. However, interpreting this data is best left to a Professional.

So my best advice is...if your recording space is a Commercial TOOL, and must perform consistently, I suggest you hire an Acoustical consultant. It will probably be the most important budget consideration you could do at this time.

That's not to say we can't help you if your budget constraints require a DIY approach.

However, if that's the case, we need TONS more information. Let us know, as there are members here who ARE professional studio designers with an abundance of experience and knowledge. But they require information in order to help you.

 

[jhbrandt]

Foley and Isolation

+1 to what Rick wrote...

Foley work invariably requires a minimum NC20 - NC15 rating and this usually means STC70+ partitions. I have recently designed one such facilities in Greece & the basement slabs are isolated - both for the control room AND the foley room.

You will have ventilation/heating-cooling to deal with as well.

Cheers,
John

 

[Bobbsy]

Another +1, with an added note that a 7 foot ceiling height is very unlikely to allow for the degree of isolation you want--you don't have much room to add isolation above your head on what (assuming standard building construction) is likely to be the worst side of the box in terms of noise penetration.

Bob

 

[RICK FITZPATRICK]

The pessimist sees the glass as half empty. The optimist sees it as half full. The realist just drains the darn thing and gets a refill!

And the Beer lover just drinks it, and THEN gets a refill!

+1 to what Rick wrote...

Thanks guys. I'm certainly no expert, but I think I have an overview of what it takes to do some of this stuff, but when it comes to actual spec's, I have to leave it to the REAL experts.

STC70+ partitions.

Holy moly...doesn't it take something like Two Leaf Masonry to achieve that John? And if so, what about the ceiling/roof or floor above? What's that take? 5 or so layers of drywall or such?

I have recently designed one such facilities in Greece & the basement slabs are isolated - both for the control room AND the foley room.

Did I mention...EXPENSIVE? Btw John, were the rooms built on TOP of the floating floors or did the floors float BETWEEN the partitions? And if they floated between, assuming TWO LEAF partitions, did the partitions have their own footings? Just curious. Always open to learning the ways pro's do these things.