Building vibration/rumble measurement and threshold

Hi John! EDIT: Oh geez, I didn't follow any of the posting rules...I apologize!! PROJECT: We are building a multi-room recording studio for the purposes of recording bands. We are planning to have 3 independent studios - 2 of which will have live rooms, iso booths, and a control room - the 3rd will be a smaller production room w/ small vocal booth. STATUS: We are in the planning phase. We are looking for an empty warehouse to build within. We are looking in Brooklyn near the L train (but hopefully not SO near that the building rumbles when it passes!). SPL: We probably would only be as loud as few 300 watt amps and a live drum set. We are planning to build rooms with sufficient isolation so that the loudest volumes would barely audible outside of the live rooms, and definitely inaudible in the other live-rooms. EXISTING CONSTRUCTION: N/A, unless you're referring to the potential spaces we are considering. The one in the question below is a 50'x100'x15' single-story garage - cement floor, cinder-block walls, wood-deck roof. BUDGET: Not completely determined yet, but somewhere between $80k - $200k. QUESTIONS: We are considering a building that is near a subway, so we'd like to measure the vibration from the train to determine how much of a problem it will be. Can you please advise on how to properly measure vibration/rumble in a building that is being considered for a recording studio? Also, what would you consider a threshold of vibration measurement to disqualify the building for the purpose of a recording studio? Thanks so much!! -Elias

Anybody?? We're kinda desperate!

Hi Elias. Welcome. Please read the forum rules for posting (click here). You seem to be missing a couple of things! :) That said, very low frequency vibration and rumble are not easy to measure, and personally I don't know how to do that. The type of infra-sound you are talking about is very likely off the bottom end of the frequency scale for the meters typically used in acoustics. As far as I know, you would need some type of accelerometer to measure that, but I wouldn't have a clue where to get one or how to use it. That's outside my area of knowledge. All I can do is point you at some research papers on the subject, if that would help. However, is it really a problem for you? Without knowing what you plan to do in your studio, that's hard to say. For example, if you are only going to be recording voice-overs, and the frequency of the vibration is down in the single digits, then you don't really have a problem: Just roll off the bass response to cut out everything below the normal range of human voice, so the rumble won't even get onto the tape. But if you are planning to record deep bass guitars, drums, and other low frequency sounds, then you don't have that option. And if you are planning a Foley studio, then I would just look elsewhere: That's a whole different thing. But the rumble of the train passing might not be your only problem: if that things blows its horn near your place, those things are damn loud, and designed to be penetrating and annoying... Then there's the other issue: if you have a good enough budget, then it is probably possible to isolate the building well enough that you could use it for pretty much everything. For example, you could float the entire studio, if you happen to have a few hundred grand laying around, or maybe just float the live room if you are on a tighter budget. But floating studios/rooms for isolating vibrations is a big deal, not done easily, and not done cheaply. So it all depends. If you explain more clearly and in greater detail what your plans are, then someone here might have a better shot at helping. I guess if you need to make a decisions fast, I would just try to measure with an ordinary sound level meter, or better still with a spectrum analyzer, and see what that shows. At least that would give a vague notion of whether or not this is feasible, and worth investing money on hiring someone who does know how to take such measurements. - Stuart -

Sorry for not following posting rules. I edited the original post with all of the requisite details (hopefully). Thanks again! -Elias

According to what Stuart said firstly find a few acceptable buildings, then measure noise level and spectrum using calibrated(!) meter at least IEC Class 2. Measurements should be taken in the most unfavorable time of the day/night/week (seek in trains timetable). With such data you will be able to choose one or two best locations. Then ask a company which makes noise and vibration measurements using IEC class 1 meters to make analysis for you. Maybe you will get some valuable tips. -Mathew-