Neighbor noise problem

[supafuzz99]

I was doing all right for 4 years until my landlord decided to rent the room next door to another studio!
During the construction process I kept mentioning the building an extra wall between the 2 studios but they didn't.

Now I can hear drums, guitars horns when they record, rendering my room useless at those times.
I measured 50 db at my mix position!

I have a meeting with them tomorrow about actually building the wall on their side [which I am offering to help with.]
the wall is 13'x30' any idea of thickness/ materials etc

thanks

[Soundman2020]

Hi there " supafuzz99", and welcome!

We'd have to know a lot more about the existing wall and the rest of the building to be able to help you with that, particularly about how the walls are built and what they are made of.

The issue is this: depending on how things are built right now, adding a new wall could make matter WORSE by REDUCING isolation in the low frequencies. In other words, you would hear the drums even louder if the new wall is not built correctly.

Even though that sounds counter-intuitive, it is very real. It is sometimes referred to as the "third leaf" problem, and is due to the phenomena of resonance. It is entirely possible that adding a new wall could create a resonant system that actually amplifies some low frequency sounds as they travel through the wall.

Here is the classic diagram that shows the problem, graphically:

2-leaf-3-leaf-classic-walls-diagram-MSM-walls.gif

That shows several different ways that an isolation wall can be built, and approximately the level of isolation it would provide. Normally you read that diagram from left to right, showing what happens as you add and remove layers, but you can also apply it right-to-left, which is your case.

If you currently have something like the situation shown as STC 50, and you added a "leaf" to that wall, the isolation could decrease by a whopping ten points, to STC 40 as shown by the drawing just to the left of that: Subjectively, the drums would be twice as loud if you did that.

Even though you introduce an extra layer of isolation between those two situations, and increase the total mass of the wall by 25%, you also create resonant conditions that completely defeat all of that, and you lose isolation.

So the first point is that the wall needs to be built properly to avoid triple-leaf or quadruple leaf effects. To do that, we need to know how the current wall is built, and the materials.

Next, the problem might not even be the wall. Your existing wall might actually be doing just fine, and sound is getting through via one of many possible "flanking paths". It could be that the ceiling or floor are transmitting the sound under or over the wall. It could be that sound is coming through the ventilation system. It could be that sound is coming through the electrical system. Or it could be that it is coming in through doors or windows, or unnoticed gaps and cracks.

There are many, many possibilities. It is not possible to just say "Add a layer of drywall" or "put 4" of OC-703 inside the wall", or whatever, without first carefully analyzing the problem from all sides, to see what it really is. Otherwise, you will likely end up spending a lot of money and get unsatisfactory results.

Acoustic isolation is a lot more complex than it looks at first glance. Hopefully there will be a simple solution in your case, but it just is not possible to say what that might be without doing the complete analysis, and correctly diagnosing the underlying cause.

- Stuart -

[supafuzz99]

That's great information. it's an old high school that's now artist spaces. So cinderblock wall between us. And yes There are some pipe chases between our spaces
So I would have to pull out the drop ceiling tiles and see what can be done maybe spray foam?

The bottom line is I may just have to move..which is a horrible choice.

This also depends on what my new neighbors are willing to do.

They built a control room so they are not affected so much by sounds coming from my room but I'm totally affected by them.

Maybe I have to build a control room to keep their sound out..

Right not I have a Daniel Lanois style 1 single room combining the live and mix area. And it's been working really well for me.

Hope this helps and thanks for your help!!

[Soundman2020]

And yes There are some pipe chases between our spaces

That sounds like a very likely possibility for flanking, yes. You can probably lift one of the ceiling tiles to get a look at what is going on up there, and then figure out what to do about it. Take a couple of photos of that, and post them here on the forum.

So I would have to pull out the drop ceiling tiles and see what can be done maybe spray foam?

Spray foam does not have a lot of uses in acoustics, since it has very little mass (low density) and is also "closed cell" at the microscopic level. It would be better to seal those gaps with proper acoustic caulk, or even with a good quality non-hardening household caulk. The type that remains soft and rubbery, even after it has fully set.

If the gap around those pipes is very large, then you could probably use some spray foam to seal the bigger part of the gaps a bit, but don't fill it completely leave a 1/4" or so on each side to add a layer of acoustic caulk, as above. You might also be able to use "backer rod" to partially close of the gaps, but in all cases you still need to finish it off with a nice layer of acoustic caulk.

A typical cinder-block wall should get you around 40 to 50 dB of isolation, if it it is very well sealed and there are no flanking paths.

Sealing is perhaps the largest single factor in improving typical isolation issues. Think of it this way: if air can get through, so can sound. Even a very tiny, insignificant-looking crack can transmit an amazing amount of sound. So your first order of business should be to ensure that both rooms are sealed just as well as they possibly can be. Inspect every square inch of both rooms, and seal anything that looks like a gap or crack. Even if it doesn't look like a gap, seal it anyway, just in case!

If the walls are unfinished surfaces, a simple coat of good quality masonry sealer, or even ordinary paint, can actually have a very beneficial effect. Cinder-block is porous (as are brick and concrete), and just sealing the surface can have a useful effect.

Next, I would check doors and windows: it is very likely that sounds gets out of their room through doors and windows, and back in to your room through doors and windows. Seal them. You could use simple weather-strip type rubber around the perimeters of all doors and windows, but even better would be to buy proper acoustic seals, including drop-down seals for the door thresholds, from some place like Zero International or one of their competitors. Not cheap, but effective. If you do that, I would also replace all hollow-core doors with solid-core doors at the same time: that can also make a big difference.

After that, I would look into the ventilation system: If there is an HVAC system in the building that provides air to the rooms, that is very likely another flanking path. That's a bit more complex to fix, but it can be done. You'd need to have silencer boxes and ducting changes specifically designed to fix that.

Finally, there might also be impact noise issues, depending on how they have their live room set up. If the drums are resting directly on the floor, and it is the same floor as yours, then getting them to build a simple isolated drum riser could make a large difference. It would also improve their recordings, which is a pluis for them too!

If you do all that and still have a problem, then the best solution would, indeed, be to build a properly isolated room for you, inside the existing space. You would likely lose 6 inches or more on all sides of the room to do that, and it would not be cheap, but potentially it could improve things by maybe 25 dB or so. That would get the 50 dB drums down to 25 dB at your mix position, which would very probably be acceptable.

So that would be how I would attack the problem: starting with the simple stuff that can actually make surprising differences, then moving up through the more complicated stuff that constitutes most of the typical problems in isolation, and only if you still have an unacceptable situation after doing all of that, then going to eh final, definitive solution of getting a fully isolated room designed and built for you.

Obviously, the costs for this start at a few tens of dollars for basic sealing, and escalate to a few hundreds of dollars for complete sealing, to a few tens of thousands of dollars for the complete "isolated room" solution. Hopefully the low-cost simple ones will do the job! But I have a feeling that won't be enough.

- Stuart -

[supafuzz99]

More great info....... I was going to mention the drum riser for them.

Caulking the pipe chases should help.
So I will take some pictures when I can.

and I'll see how the meeting goes with my neighbors

thanks again