checking outdoor noise level with Radio Shack SLM

i was checking outdoor noise level with Radio Shack SLM at outdoor sites. because i might construct new studio from the ground. but when wind blows, the SLM indicates more than 80 db. i think i might need a windscreen for the SLM. but i have no idea about how to do. could i just use normal(regular) dynamic mic windscreen for Radio Shack SPL?

I'd avoid measuring at all when it's windy, if only because the wind noise itself will skew the readings. --Ethan

Just an addition. Windscreens for SLM's seem me thicker than the ones used inside. That Beringer MC 8000 e.g. has a very thin windscreen, which certainly doesn't match standard measurement mic windscreens for outside use. Standard it looks like this: http://www.dixellasia.com/customer_imag ... 1_5342.jpg To have an idea about shape and size. You're looking at a 1/2" microphone. If assuming correct Is the RS not a 1" mic? With the right windscreen the standards I know allow outside measurements upto 5 m/sec. But I've no idea in how far the RS larger diafragm should influence this, nor where to get such a windscreen for that size of mic. Maybe you can use one of a 1/2" mic? I just measured one I have here of B&K = type UA 0237 It's a sphere with a diameter of +/- 9 cm and a small hole fore the 1/2" mic. But I know other brands can be somewhat smaller still fulfilling requirements.

Ethan Winer wrote:

I'd avoid measuring at all when it's windy, if only because the wind noise itself will skew the readings.

I second that. Only take measurements when it's near silence. Preferably early in the morning when there's minimum background noise like cars, people, birds etc. And do it on a clear day, no rain wind etc. Also take note of passing airplanes etc.

Eric, > If assuming correct Is the RS not a 1" mic? < I never took my RS meter apart, but the capsule looks to be about half an inch in diameter, or maybe a bit less. --Ethan

Thanks Ethan, I never saw them than on pictures. Of course measuring without any wind is best and possible when one can measure whenever. But even a little wind can be disturbing if exciting the membrane. With about 1/2" I think it must be not too difficult to find suitable windscreens (doesn't cost too much). If measuring outside shouldn't be possible with some wind, then environmental acousticians couldn't make appointments anymore with their customers. One can't plan the wind very well. Long-term measurements should become (in many regions) practically impossible. Best regards Eric Edited: For the interested ones: Types of B&K windscreens: http://www.bksv.com/default.asp?ID=3576 The effect of different types of windscreens and other 'outside use' microphone accessories: http://www.bksv.com/pdf/Bp1650.pdf .

I use a foam clown nose as a windscreen for my earthworks mics. This isn't for measurement though, its for screaming vocals.

The RS meter has a 1" mic. (Ethan: Measure the o.d. to get "standard" mic diam.) Finding a windscreen for it won't be easy. I would agree with others here - measure on a calm day if all you have is the RS meter.

Eric_Desart wrote:

Thanks Ethan, Long-term measurements should become (in many regions) practically impossible. Best regards Eric .

Good to know that I will need to bring my wind breaker when I came to Antwerp in October! :D

lovecow wrote:

The RS meter has a 1" mic. (Ethan: Measure the o.d. to get "standard" mic diam.)

I just measured the inside of my RS meter and it's 5/8 inch. Why the inside? Because microphone diameters refer to the diaphragm size, not the housing diameter! :) --Ethan

myfipie wrote:

Good to know that I will need to bring my wind breaker when I came to Antwerp in October! :D

:mrgreen: There's still a wide range between needing a wind breaker ( :) whatever that is) and no wind at all. When crossing the ocean, you'll notice that we have relative normal civilisations (notice the "relative") here with relative normal weather conditions, and a bit less than normal people. :)

Eric_Desart wrote:

myfipie wrote:

When crossing the ocean, you'll notice that we have relative normal civilisations (notice the "relative") here with relative normal weather conditions, and a bit less than normal people. :)

Actually I have found that most European countries are much more civilized then the USA. May it be social or modern building reasons. A wind breaker is a jacket that helps keep the wind from hitting your skin. Glenn

Ethan Winer wrote:

I just measured the inside of my RS meter and it's 5/8 inch. Why the inside? Because microphone diameters refer to the diaphragm size, not the housing diameter! :)

You're not wrong. But we're kind of talking about different things. When discussing the size of an SLM microphone for fitting things like windscreens and calibrators, it is the outside diameter that is referenced. Hence my "standard" in quotes. I am referring to microphone sizing for SLMs, as opposed to something that would be more broadly applied to any microphone. The terminology to which you refer would be applicable to, e.g., a large diaphragm condenser mic for recording, which might have a 1" diameter mic contained within the (much larger and sometimes oddly shaped :) ) protective screen. On a more "professional" (e.g., ANSI Type 1 or 2) SLM, the actual microphone element would be sized such that the o.d. of the protective screen (not to be confused with the windscreen) is a "standard" 1/2" or 1". (Actually, the "standard" designation is more typically metric - 13 or 25 mm, respectively.) The diaphragm size itself would be a little smaller than the protective screen into which it is fit. The reason this is done is to accommodate "standardized" fittings on things like calibrators. The RS meter is unique. It has a rather bulky protective screen relative to more "professional" SLMs. (A "professional" SLM with a 1" mic would have an element that was much closer to 1" diam. than the RS' 5/8" diam.) However, the RS SLM can be calibrated with a standard 1" (25 mm) fitting on, e.g., an ACO calibrator. For the topic at hand, a windscreen for the RS SLM would be difficult to find since, not only is it a 1" diameter, but it is also rather "stubby". :D

Jeff, > When discussing the size of an SLM microphone for fitting things like windscreens and calibrators, it is the outside diameter that is referenced. < Gotcha, and good point. When I think of microphone diameters, it's always the diaphragm size because that's what affects accuracy at high frequencies. BTW, I'm loving my tiny-diaphragm DPA 4090. I bought it for measuring, but it's awesome for recording. I'm up to 68 tracks on my current project, and I've used the DPA for every one of them! > For the topic at hand, a windscreen for the RS SLM would be difficult to find since, not only is it a 1" diameter, but it is also rather "stubby". :D < I just measured mine again - the OD is 7/8" and the "stubby" part sticks out only 7/16". Fitting an RS meter with a high quality wind screen seems like drinking a glass of fine sherry after a meal at Burger King. :? --Ethan