REBUILDING EXISTING LIVE ROOM

[rhaft001]

Hey All,
Im new here and rather in experienced so Ill give a little info and am asking for advice on the project I am tackling. I am a partner in a studio that is in a warehouse complex and we inherited a space that had a studio built out in it. Its not ideal but isolation from live room to control room is solid and things have been good for a few years. Recently a gym (crossfit style) moved in to the unit adjacent to us and its became a nightmare. We can here leakage from music, screaming, and there is audible and physical resonance of them dropping weights on the floor making our live room almost unuseable for clients while they are operating.

My partners and I have been exploring all options including moving to a new space and figured the most cost efficient way to go about it is to demolish the live room and likely float a floor and rebuild the room.

The room is 24x21x14 feet. Thats roughly the dimensions of the warehouse walls as well as it seems the initial build did not leave any air gaps in the walls from the concrete ones of the space shell.

We have all the non parallel build stuff mapped out but I am looking for advice on the best way to accomplish isolation for the gym issue described above. Theres all a new machine shop 2 units down from us where we can audibly here them using some sort of air compressor in the 100-200hz region which we are trying to isolate from as well.

I am making an assumption that a floated floor is a must to get away from the impact of weights hitting the floor. Would we need to fix the walls to this floated floor as well with the ceiling fixed to that? Thanks in advance for any response and pardon any noob questions. Cheers!

RH

[DanDan]

You are welcome. Probably best to include where you are located in your Profile......
A floating floor should address structure borne sound, but Music and Screaming has to be Airborne I reckon. Probably ditto the Machine shop.

[Waka]

Yep I agree with other Dan (or am I other Dan?? ).

The weights dropping on the floor will be helped by a floating floor yes.

But to build an effective floating floor is not easy. The floor needs to float on carefully calculated springs/pads. If the weight in the room changes then the load changes and they could be over/under compressed.

In a live room this will likely happen a lot. There's a big difference between a single vocalist using the room and a 7 piece rock band with 4 x 12 cabs.

The usual way this problem is tackled, is by having your floating floor be a heavy slab of thick concrete to begin with. That way any load changes in the room are small in comparison to the massively heavy slab.
It also usually rules out wooden floating floors for most reasonably sized live rooms.

When floating the floor (thick poured concrete slab), you also need to float your walls, or else you get the structural sound transmission anyway.

You can technically float your walls separately and then float the floor inside the room, but it's generally easier for construction to float a big slab of reinforced concrete and build the whole studio on top of it.

This decouples the whole floating inner "room" from the outer "room".

You need use heavy industrial isolation products for this. Floating a floor is not a job for the faint hearted!

You will need a structural engineer to run the calculations for the floor loads etc.

But don't let that put you off. Whoever your supplier is for your isolation springs/pads should be able to provide calculations for correct deflection/loading.

You may find after reading this that actually a new location would be cheaper after all, (which may be the case), but you need to consider the potential for noisy neighbours again in future locations.

If you float your floor you can achieve significant isolation from your neighbours, it all depends on budget and careful design and construction.

Most important things to consider:
Door isolation,
HVAC needs and maintaining isolation,
Preventing plumbing and electrical penetrations from ruining your isolation.

Best thing to do to start with would be to get a good quality SPL meter (50-100£$€) and measure the actual levels you need to isolate. Measure on C weighting and slow-response to focus on the low frequencies that are most difficult to isolate.

Have you got a budget and timescale?

If you are short on budget, you need lots of time to learn and design this right before you start construction.

If you are short on time you need to spend a part of your budget on getting a studio designer to draw you up some plans.

For a pro studio, if you don't have 6 months to a year of time to learn how to do this properly before you set off you will waste more money than your studio designer will cost. Good studio isolation is not easy to achieve and is expensive. Especially structural sound isolation!

If you choose to use a designer your can PM John Sayers he might be able to take you on/point you in the right direction.

If you go DIY please post your questions, progress and photos here.

All the best with your build!

Dan

[DanDan]

Just a FYI, as a Noise Consultant I have owned and used a few different SLMs.
Now I am increasingly using iPhone apps. For pennies they offer Leq which is way better than visually trying to average changing levels.
From new they are rarely more than a dB or 2 off, and they can be calibrated to a reference level.
This one is very good quality and free..... https://www.cdc.gov/niosh/topics/noise/app.html
Note many traditional SLM's didn't include Z rating, which is even flatter than C.
Faberacoustical and Studiosixdigital also have great products.

[rhaft001]

Thank you guys for this input, it is REALLY appreciated. Unfortunately we are kind of pressed for time and budget. I think we have around 10-15k to try to make it happen as this was a rather unexpected situation as we have had no problem for 5 years almost. We are consulting with a studio designer locally in Miami where we are and tossing around the ideas. The concept of doing the floor as a slab of concrete floating seems the most ideal thing to do as there a variety of different setups happening in the room (Rock bands, Chamber ensembles, and just hip hop). That load on the floor varies alot. With that budget is assumed this is impossible to pull off half DIY and half professionally? We have all the HVAC and electrical totally sorted and just the physical buildout is our goal for the isolation and obviously safety.

[DanDan]

Some pondering material for you and your local Aoustician.
I wonder how much of the sound transmission is structure borne and how much air borne?
I noticed you used the word physical regarding your perception of the weights being dropped. Could there be just a small amount of tactile information coming from your feet, convoluted with the air borne banging?
If you do have slab transmission, perhaps you could cut it. You would presumably then both have slabs on grade, which may not communicate with each other much or at all. Cutting concrete, a tough job, but I presume you would have to do that to replace your current slab anyway.
In addition to whatever you end up doing, are there possibilities at source? Maybe these muscle types like the big noise, but it strikes me that it might be at a danger level.
In which case the owner might be amenable to softening it at source. Sandpit?

[Waka]

I wonder how much of the sound transmission is structure borne and how much air borne?

I had a similar thought. Can you describe your current wall/floor construction? Can you post a floor plan?

Is your studio designer able to visit the site and measure the source of the problem noise?
If they are acting remotely, you can do this yourself. To find airbourne noise sources, download a program called REW and walk around the room with your microphone searching for the source of noise in real time. Focus around doors, HVAC vents and any electrical penetrations.

DanDan may have suggestions of how to measure structure bourne noise.

I think we have around 10-15k to try to make it happen as this was a rather unexpected situation as we have had no problem for 5 years almost.

I think you might be a bit short here for a rebuild, unless you can save all of your flooring and current acoustic treatments. You may find you want to bulk up the outer leaf of your isolation in the process. I would want $25000 on hand just in case. My own full build in the UK, building a free standing multipurpose control/tracking room about half the size of yours has costed £12-£15000 ($15 - $20000) almost entirely DIY. You can save on not having to buy hvac/doors/or electrical or pay for building and planning permits though. So you might squeeze by, but I would have a back up on hand ready.

Dan

[DanDan]

I wonder how much of the sound transmission is structure borne and how much air borne?

Oddly a current issue for me. Just recently Bob Katz did some extensive measurement of vibration travelling from speaker to floor and onwards.
I was a sort of devil's advocate, kept him honest....
He hired an Accelerometer rig. Interesting results but no answer to the big one.... can you hear the floor borne sound, or the damage it does to the direct.

In this case I was just encouraging an assessment of some kind. Place a hand on the floor, bare feet. Use a drum stick lightly squeezed between floor and outer ear.
There are Mechanics stethoscopes for listening to gears and engines
A Piezo pickup fed into REW......

Note, the floor borne sound will be significant earlier than the air borne. Sound travels about ten times faster in concrete.

Perhaps you could persuade REW to show information before the big airborne spike. Using a mic in a normal position this should show the levels of the way earlier faster path vs the regular air one.

I became an Acoustician towards the end of a life long Sound Eng career. Very little build experience. Perhaps someone experienced will join in. i.e. Would cutting the existing slab all the way through diminish enough the banging in one from travelling to the other.