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SPL (dB) Meter Market Knowledge Needed, Please Help

post #1 of 12
6/9/05 at 8:44pm
Thread Starter 
I want to get an SPL meter. I have wanted to get one for a really long time, but I have no clue what to look for. I want one that goes from 0-180 dB and has a good amount of feattres, only problem is is that even the most expensive SPL meters on ebay only have ranges of ~30-140 dB. So obviously these things are much less accurate then I desire, but I don't even know how accurate a dB meter I want.

Basicly I am a SPL meter noob and have no freakin' clue what the heck I want. I want something that can handle the loudest enviroment I will send at it and handle my rural nothingness neaiborhood at night, is that doable without spending hundreds of thousands of dollars? How accurate of a meter do I need for just random measureing/stereo measure? What features do I look for, what model meter is the best deal?

All kinds of questions, basicly like I said I have no clue what makes one better than the other and one $500 and the other one $60. Cause right now it doesn't seem like much is seperating them.

Any asistance would be most appreciated, them maybe I can take the dive into ownership of one of these nifty as heck meters.
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post #2 of 12
6/9/05 at 9:49pm
Why do you need a meter that measures up to 180 dB? What environment will it ever need to measure that's even anywhere near that loud? You'd be deaf in seconds!
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post #3 of 12
6/9/05 at 10:03pm
The official DB Drag meter....

http://www.termpro.com/term-lab/index.asp


Surf the termpro forum, theres lots of discussions there.

Garrett
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post #4 of 12
6/10/05 at 9:05am
Quote:
Originally Posted by PTheD
I want one that goes from 0-180 dB and has a good amount of feattres, only problem is is that even the most expensive SPL meters on ebay only have ranges of ~30-140 dB.
180 dB??? That would be roughly 10000 times the noise of a jet airplane taking off (heard from a couple of meters distance)! I can't imagine what would be able to make that kind of a noise - except 10000 jet airplanes taking off at the same time at the same airport .

On the other hand, 0dB is rather hard to find either. If the noise level at my appartment was below 20 dB, I would have been in "7-th heaven". Typical noise level in a _quiet_ appartment is around 30 dB (as far as I know)... When the appliances are working, it goes up to 40 dB. etc.

I think the range 30...140 dB is more than adequate for most practical purposes.
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post #5 of 12
6/10/05 at 10:54am
Yeah, there basically is no such thing as 180dB for all realistic purposes. The Radioshack SPL meters are common and well regarded. You need one that at least does "A weighting" and has a couple different averaging modes.
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post #6 of 12
6/10/05 at 6:49pm
Thread Starter 
BTW, I do realise the scientific dificultys with generating enough ossolation in any given medium for a dB level of 180 to be reached, and the practical imposibilty of reaching absolute zero and 0 dB, I'm not two years old you know, I do know more than just the sun is brite and owww cat!

What I don't know is the accuracy and precisison that I would require for my lose use of my intended to get meter.
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post #7 of 12
6/10/05 at 7:32pm
The wider the range of SPLs the meter is designed to handle, the less accurate it will tend to be. A meter designed to handle 180dB (a rocket launch) will tend to be inaccurate for more realistic measurements (80-110dB), because to handle 180dB the meter needs to handle 100 million times as much power as it needs for a more reasonable signal (100dB). Most reasonably priced measurement equipment is accurate to fewer than about 5 significant digits. You do the math -- the 100dB signal is basically just noise to measurement gear that can handle 180dB.
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post #8 of 12
6/10/05 at 7:38pm
Thread Starter 
Quote:
Originally Posted by AlanY
The wider the range of SPLs the meter is designed to handle, the less accurate it will tend to be. A meter designed to handle 180dB (a rocket launch) will tend to be inaccurate for more realistic measurements (80-110dB), because to handle 180dB the meter needs to handle 100 million times as much power as it needs for a more reasonable signal (100dB). Most reasonably priced measurement equipment is accurate to fewer than about 5 significant digits. You do the math -- the 100dB signal is basically just noise to measurement gear that can handle 180dB.
Like very quite ambiant noise that is.
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post #9 of 12
6/10/05 at 8:01pm
Quote:
Originally Posted by PTheD
Like very quite ambiant noise that is.
You could think of it that way. I actually meant measurement noise. For instance, if you have a piece of lab gear that can measure pH of a solution with an accuracy of five significant digits, and you measured a liquid with a pH of exactly 7, the equipment readout might read 7.000000, but it probably won't; it could just as likely read 7.000022 or 6.999983. Regardless of what the actual readout says, a person in the lab needs to realize that only the first 5 digits can be depended on -- anything after that is just noise.

Like I said, even for lab-quality gear, it's hard to get more than about 5 significant digits of accuracy in any kind of measurement gear, because of real-world physical limitations. 5 significant digits corresponds to a 50dB difference in power or a 100dB difference in voltage. So it's not surprising that most commercial meters have a range of about 30dB to 140dB. That's roughly 110dB of range, which is pushing the limit of any reasonable piece of measurement equipment. You won't find better in a single meter, except extremely expensive special purpose research gear.
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post #10 of 12
6/10/05 at 8:41pm
Thread Starter 
Quote:
Originally Posted by AlanY
You could think of it that way. I actually meant measurement noise. For instance, if you have a piece of lab gear that can measure pH of a solution with an accuracy of five significant digits, and you measured a liquid with a pH of exactly 7, the equipment readout might read 7.000000, but it probably won't; it could just as likely read 7.000022 or 6.999983. Regardless of what the actual readout says, a person in the lab needs to realize that only the first 5 digits can be depended on -- anything after that is just noise.

Like I said, even for lab-quality gear, it's hard to get more than about 5 significant digits of accuracy in any kind of measurement gear, because of real-world physical limitations. 5 significant digits corresponds to a 50dB difference in power or a 100dB difference in voltage. So it's not surprising that most commercial meters have a range of about 30dB to 140dB. That's roughly 110dB of range, which is pushing the limit of any reasonable piece of measurement equipment. You won't find better in a single meter, except extremely expensive special purpose research gear.

There we go, thanks, that is something that I would be looking for. Good info.
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post #11 of 12
8/1/11 at 3:40pm

i have a system in a ford ranger that can hit 157.3 db, if you have a meter that maxes out at 160 the hi end will be less accurate. therefor harder to determine what hertz level you need to maximize your db output...this from an spl comp. guy...my advise...if you are serious, then spend the money. if you arent super serious dont even buy one. just take it to any respectable audio store...they will test it for free

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post #12 of 12
8/1/11 at 10:58pm

I accidentally hit the back arrow and lost my first post, but basically...

 

I use a RadioShack sound level meter; it goes in steps of 10 from 60-120 (measuring about 50-130), and I've never felt the need for a wider range in anything audio related. If you were going to go back in time and measure the eruption of Krakatoa you might need something in the 180 db range, but in the modern world even the space shuttle isn't that loud. Anything much over 120 db is dangerous to your hearing, and 180 db is probably even physically dangerous.

 

As other people have said, a the range of measurement and the accuracy of measurement typically have an inverse relationship; the wider the range, the less accurate the measurement. Ideally, for an accurate measurement you want a device with a relatively tight range centered on the range you intend to measure. Without knowing what you're planning on using the meter for I can't be more specific, but 30-140 will cover pretty much everything you can throw at it.

 

My computer room (which I'm in now) has an ambient noise level of about 51 db, with my computer and its three huge fans switched on under a minimal load. I suppose an outdoor street in a rural neighborhood would certainly be quieter, probably even a lot quieter - I don't know, since I can't measure that low. From memory, I think that the sound of leaves rustling is about 20 db and a quiet whisper is 30 db. At the other end, 140 db is many, many times louder than the sound of a circular saw cutting wood. It's louder than a pneumatic riveter. It's about the same level as a gun firing, depending on the gun. Above 140 db it's hard to find examples that you would ever encounter without already being at grave personal risk due to proximity.

 

For ordinary listening, 60-120 is certainly enough; 30-140 would be more than enough for anything musical you could ever throw at it, certainly. If you could elaborate a bit more about what you intend to use this decibel meter for, people could perhaps give more specific advice.

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