Need Help Stopping Low Frequencies. Suggestions Please!

[justinmichael]

Fellow Gearslutz,

I need your help! I just purchased a live/work loft and I plan on having my studio inside the unit. I ran some tests with my monitors (Dynaudio BM6a's) and I found that the high frequencies were NOT passing through the walls into to the other lofts, however the bass could be heard in the nextdoor units.

I contacted the developer and they told me that the lofts were built with a double wall structure.. (drywall --> 4 inch stud --> insulation --> 2 inches of dead air ---> insulation -->4 inch stud --> drywall) . They told me that the walls were about 11 - 12 inches thick and were not touching eachother to stop any vibrations. I guess this is not enough to stop low end frequencies.

how can I prevent the bass from leaking? any recommendations?
Can I build something over the existing dry walls?
Will real traps / bass traps be enough to absorb some low frequencies?
Please give me all your suggestions..

I have looked at websites such as Soundproofing and Acoustic Materials

has anyone used this companies materials?

thanks,
Justin

[avare]

The wall construction you described has around 15 dB isolation at 50 Hz and 20 dB at 63 Hz. What are flanking paths like? Is the sound coming from the floor? The ceiling? Through air ducts?

Low end isolation is expensive. Simple cheap solutions do not exist. The link you provided I did not see any low end isolation on.

Adding extra layers of drywall with will help. Assuming the wall is the weak link.

Bass traps treat sound inside the room, not isolation

Try and determine where sound is coming from as a first step.

Andre

[avare]

I just did some research on that site AND STAY AWAY FROM IT. Their recommendations for improving sound isolation of an existing system creates a triple leaf. This would reduce the isolation at low frequencies!

They push MLV,or an equivalent, which is not cost effective.

There no such thing as Soundprooffoam, which is the name of the website.

Andre

[justinmichael]

Originally Posted by avare

Try and determine where sound is coming from as a first step.

Andre

The sound is definitely coming from the walls..
the floor and ceiling is concrete / cement.. very solid

is there anyway to treat the wall? bass traps in the corners?
will real traps reduce any low freq from escaping?

[justinmichael]

Originally Posted by avare

I just did some research on that site AND STAY AWAY FROM IT. Their recommendations for improving sound isolation of an existing system creates a triple leaf. This would reduce the isolation at low frequencies!

what do you mean triple leaf?

[larrykane]

Originally Posted by justinmichael

Fellow Gearslutz,

I need your help! I just purchased a live/work loft and I plan on having my studio inside the unit. I ran some tests with my monitors (Dynaudio BM6a's) and I found that the high frequencies were NOT passing through the walls into to the other lofts, however the bass could be heard in the nextdoor units.

I contacted the developer and they told me that the lofts were built with a double wall structure.. (drywall --> 4 inch stud --> insulation --> 2 inches of dead air ---> insulation -->4 inch stud --> drywall) . They told me that the walls were about 11 - 12 inches thick and were not touching eachother to stop any vibrations. I guess this is not enough to stop low end frequencies.

how can I prevent the bass from leaking? any recommendations?
Can I build something over the existing dry walls?
Will real traps / bass traps be enough to absorb some low frequencies?
Please give me all your suggestions..

I have looked at websites such as Soundproofing and Acoustic Materials

has anyone used this companies materials?

thanks,
Justin

As you state the floors are concrete you should be able to stack concrete block without mortar and create a room within a room. How high are your ceilings?

[justinmichael]

Originally Posted by larrykane

As you state the floors are concrete you should be able to stack concrete block without mortar and create a room within a room. How high are your ceilings?

Ceilings are about 12 feet. The unit is about 1100 sq. ft. total.
It will also be a living space.. so if possible, I would like to reduce any sq footage loss.

[docbop]

Is there any tenants above your unit? If not maybe hanging your speakers to avoid coupling with the floor.

[justinmichael]

Originally Posted by docbop

Is there any tenants above your unit? If not maybe hanging your speakers to avoid coupling with the floor.

yes, there are tenants upstairs..

but the main problem is the units to the left and right of me.

there is no leakage upstairs or downstairs.. most likely because of the cement/concrete ceilings and floors.

[avare]

Originally Posted by justinmichael

The sound is definitely coming from the walls..
the floor and ceiling is concrete / cement.. very solid

Great! You have identified the source.

is there anyway to treat the wall? bass traps in the corners?
will real traps reduce any low freq from escaping?

Traps are for treating the sound of the room, not the sound isolation of the room.

what do you mean triple leaf?

Walls (and floors/ceilings) have different layers of materials with an air gap between them. The usual inside wall has:

drywall (leaf 1)
air gap with studs
drywall (leaf 2)

The site recommends for upgrading a current wall to put strapping and channel on hte existing wall, and then an additional layer (leaf). This is then:

old drywall (leaf 1)
air gap with studs (airgap)
old drywall (leaf 2)
air gap with strapping and channel (air gap 2)
new drywall (leaf 3)

The effect of triple leafs is not intuitive. It is difficult to find test data on them because it is an inferior design for sound isolation in most instances. To give an idea what an effect triple leafing, have a look at fig 73 on pdf page 72, and the drawings before the fig. in NRC IR 811. You don't have to get into much techy detail. The higher the lines in the graph, the better the isolation. The best system and the second worst use exactly the same material. The only difference being the location of the material, with second worst system being a triple leaf.

Also note how the low frequency isolation remains in the same area. Low frequency isolation requires mass and decoupling. With the construction of wall you have, decoupling is fine. What is left is adding mass to the wall.

Andre