I built 2 rooms within a cynder-block building but.....

[youngmain]

Ok, I was on a limited budget and found a building(great price) on a very busy street and about 150 yards aways from rail lines. I built two rooms within the building using a dyrwall/auralex type sheetblock/drywall sandwich. Small town, and all the businesses are pretty close to the rail road anyway. Low end Rumble from the train is non existent but I can faintly hear deep rumble from certain traffic that passes on the street. I mean, it could be more phsychological because I can click my nails and it sounds louder than the rumble by far. So, how can I measure low end frequencies? What could I put up on the wall to block some low end frequencies and mid frequencies from the Fhukin honking train?(those sons of bitches are loud and I cant waite to get enough money to move!!!!!) dfegad I HATE TRAINS IF IM NOT RECORDING THEM!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Ethan Winer]

Originally Posted by youngmain

how can I measure low end frequencies?

Use an omni microphone, recorded into an audio editor like Sound Forge with a spectrum analyzer plug-in.

--Ethan

[John Suitcase]

If you're doing rock stuff, I wouldn't stress about it. If you're doing quiet acoustic sources, on the other hand, you might have to move. What is the roof/ceiling made out of? Sometimes a lot of sound comes in that way, especially in commercial spaces.

[youngmain]

The roof is plywood. The ceiling is soundboard/auralex type material/drywall sandwich. I think I am going to cover the roof with real auralex this time and do the analyzation. My only problem is I record vocals in their and might be forced to buy auralex sheet block and cover the in inside of the room as well. Its quiet in their so I might need to analyze first to see if its really a problem.

[Weasel9992]

True isolation is no easy task. What you're describing doesn't sound like nearly enough mass to prevent low end transfer. I also don't see any decoupling going on.

The problem is, the room will only be as quiet as its weakest point of isolation...that means walls, floor, ceiling, doors and windows (if applicable) all have to be addressed in a wholistic treatment plan. Unless the room is purpose built, it will typically require some pretty serious construction to keep all the noise out. I'd like to give you better news, but I think you'd nearly have to go back down to the blocks and start over to get what you're wanting.

The John Sayers forum has some great topics on isolation and how to achieve it from a construction standpoint.

Frank

EDIT: ah...so we're talking about cinder block. That's much better than wood frame, but still wouldn't be enough to provide complete isolation.

[jwl]

Isolation requires mass, airtightness, and specific construction techniques.

Dampeners such as sheetblock and Green Glue can help on top of that.

The first thing you need to do is figure out where the sound is coming in. Next time you hear the traffic patterns, get down onto the floor and put your ear to the ground. Do you hear it in the floor? If so, this is likely flanking noise coming through the slab, so you might be out of luck.

On the other hand, if all is quiet on the floor but you can hear it on the walls, then the sound could be coming in from there. Are your inner walls isolated from the cinderblocks? Is there a flanking path from the cinderblock to the inner wall structure? What about sheetrock? Do you have it up on both sides of your framing, or is the sheetrock/soundblock/sheetrock sandwich mounted on one side of the frame with nothing on the other? Do you have insulation between the cinderblock and the inner wall frame? Perhaps you need more mass on your walls.

If the sound is louder just in the room than when your ear is up against the floor or the walls, then I'd look for an air leak somewhere. How is sound getting in? HVAC? Are your walls airtight (ie, they've been sealed with acoustic caulk?)

Just some ideas.... to get some answers we need more info.