# SPL meters on Android or smartphone



## bambino (Feb 21, 2010)

Has anyone used the DB meters on the Droid or any other smartphone? I have 3 different ones downloaded and all seem to read fairly similar results. I was just curious as to if any of you have used them and compared them to the real deal.


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## mdrake (Jan 31, 2008)

I have one on my phone and I am not sure why I have not compared it to my RS meter. :doh:


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## bambino (Feb 21, 2010)

mdrake said:


> I have one on my phone and I am not sure why I have not compared it to my RS meter. :doh:


I don't have a real SPL meter but would like to know how accurate the ones on the smartphone are. Just may have to buy one and test it.:T


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## mdrake (Jan 31, 2008)

bambino said:


> I don't have a real SPL meter but would like to know how accurate the ones on the smatphone are. Just may have to buy one and test it.:T


What is your favorite spl app? I will test it. I am currious as well, now that you bring it up. :T

Matt


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## boarderc577 (Feb 2, 2010)

I'm extremely interested in the resultant for this


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## bambino (Feb 21, 2010)

Out of the 3 i have downloaded i like the one called noise meter the most, the only thing i don't like about it is that it doesn't hold peak.The other i have is called deciBel which i do believe holds the peak. The third one is called sound meter and looks like a speedometer but also doesn't hold peak. 
I'm curious as to the results you get, let me know. 
Thanks, Bambino.:T

P.S. they are all free Apps but 1 or 2 of them are upgrdeable for a price.


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## tonyvdb (Sep 5, 2007)

Ive been using "AudioTools" for the iPhone. so far testing it against my Galaxy CM140 it seems very close. The tools app has other features like spectrum annalizer, Audio test tones, polarity tests and many other options.


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## JBrax (Oct 13, 2011)

I also use Audio Tool for the iPhone however I don't have anything to compare it to. I only use it when I want to see just how loud I'm playing my movies.


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## ls1_sounds (Dec 14, 2010)

I tried one a while back, but now I can't remember the name. It had an RTA display, and peak hold capability, but was really slow to sample and update readings.

Regarding accuracy, I doubt there is any to speak of over the frequency ranges we are interested in. Even if we had an accurate source, and established reference levels on our phone apps, I'm not sure the mics would hold any degree of accuracy over time.


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## MaxCast (Apr 26, 2008)

I too have audio tools FFT app. Easy to use but have no idea on the accuracy. I've read the mic on the phone4 is limiting its accuracy as it is set for voice optimization/background nice reduction, heh as it probably should.


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## ls1_sounds (Dec 14, 2010)

MaxCast said:


> I too have audio tools FFT app. Easy to use but have no idea on the accuracy. I've read the mic on the phone4 is limiting its accuracy as it is set for voice optimization/background nice reduction, heh as it probably should.


Exactly right! The apps are still fun to use though. My daughter likes to use the gStrings app to tune her guitar, which works really well since it is measuring frequency instead of amplitude.

I am a metrologist, but unfortunately I no longer have access to the equipment required to check microphone accuracy.  At my last job, I could have at least measured a Moto Droid 3 for us!


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## bambino (Feb 21, 2010)

ls1_sounds said:


> I tried one a while back, but now I can't remember the name. It had an RTA display, and peak hold capability, but was really slow to sample and update readings. if we had an accurate source, and established reference levels on our phone apps, I'm not sure the mics would hold any degree of accuracy over time.


About the Mics on the Phone, i would imagine that there accuracy would get thrown off over time with say lint build up or other gunk that gets clogged in it.


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## SAC (Dec 3, 2009)

I may as well stomp on the ant hill here...not aimed at anyone in particular, but at the broader topic which I can't help but feel is 'much ado about very little', in the hopes of reducing a bit of the associated worry.... 

Threads on this forum (and on some others) regarding SPL meters are approaching the regularity and character associated with debates over speaker wire on some sites.

While folks debate which ~$19-$45 meter is 'best', I have yet to hear a necessary reason that one have a calibrated meter capable or reliably indicating an ABSOLUTE SPL level.

I have heard even less as to how one can even compare of determine an absolute level on an SPL meter. Between the weighting schemes and their deviation, as well as variations in the source stimulus - be it a single tone or multiplexed tomes or white noise or pink noise, how exactly do you determine the actual energy, let alone compare one with the other?????? And this is is fundamental to how an SPL meter works.

And then we have the continuing preoccupation with 'calibration'!
Considering that we all assume that all noise sources are equivalent and will be read identically by the SPL meter (NOT!), who has a need for absolute levels?

The fact is, the mic in ALL cases is a limiting factor. Using a iPhone or a large capsule SPL meter and expecting 'calibrated' performance is an oxymoron.

And that assumes stimuli with similar characteristics measured with the same meter. Any variation and the comparison is invalid.

The fact is, they are fine for relative level readings.
If you compare two sources with the same meter in a similar manner, the relative comparison is fine. Is it absolutely accurate? Does it matter?
And I have yet to read of a compelling reason that someone requires an absolute reading.

In fact I have only encountered this a few times, and in all of those cases, an SPL meter was not admissible - not even a legitimately calibrated SPL meter. While that may have given one reason to suspect a problem, in each case what was actually required for submission in court was full blown noise level analysis (NLA) requiring a completely calibrated measurement platform. And for the certified SPL meters used by some police departments, the units cost over $2000 each!

The fact is, for 99% of the users here, ANY of the cheap SPL meters are fine. 

They will provide adequate relative indications of level sufficient to match multiple sources.
And they are sufficient to establish a relative level in measurement programs like REW.

Everything else is simply obsessive - lots of worry for no practical meaningful purpose.

So, ANY of them will work sufficiently well in order to compare two or more sources with identical stimuli using the same meter for their relative similarity or differences. And they are all sufficiently accurate to set a general reference level.

And if they are not, one best start saving for an Extech calibrator which depending on single or dual levels, will generally cost you in the ball park of $300 or $400.

And suddenly the cost of the meter itself does not look so critical.....

And ALL of this assumes the instrument is treated and stored with care!


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## bambino (Feb 21, 2010)

Like one of the posters said they are for fun and i might add that if used for your system alone could be of great benefit. But they are certainly not made for pros.:T

Good post by the way,Sac


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## HUSKER (Feb 11, 2009)

:boxer:Speaker Wire VS SPL meters on Android or smartphone:boxer:

Husker


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## ls1_sounds (Dec 14, 2010)

I had no idea that this was such a passionate subject here. Some last comments before I bow out of this thread:

SPL meters are generally not accurate devices, but they are at least specified by the manufacturer to provide a certain level of measurement accuracy across a frequency range. When reviewing even OEM calibration reports, it is likely that you will find many SPL meters are verified to perform to their specified accuracy, but they are only tested at a frequency of 1 kHz, not across their full specified frequency range. In our ISO 17025 accredited calibration lab, we automated the process and instead verified every meter across its full specified frequency range. Many failed our more stringent test even when brand new, or older but with a fresh OEM calibration certificate. I would not worry about whether the SPL meter is spec'd to ±0.5 or ±1.0 dB, you can usually exceed this value easily by just changing the orientation of your meter to the source. For this reason, I agree with the statement that cheap SPL meters are perfectly fine for the vast majority of our purposes.

The most common SPL meter use is to ensure the hearing safety of employees in loud environments (industrial, aircraft, etc.), not as a reference standard for frequency response calibration even though many of us use them successfully for this purpose. Regarding absolute vs. relative measurements, nearly all measurements are relative to something else in their traceability chain to a National Measurement Office (like NIST in the US). The capabilities of nearly all measuring devices are limited, but that does not make them unsuitable. 

With all of that being said, I return to the original topic: I cannot find where mics installed in cell phones are spec'd for accuracy at all. As pointed out earlier, they are optimized to pick up human voice frequencies, plus they live in a very harsh environment. I would not expect much from them, but the apps are still suitable for the purposes of entertainment.


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## bambino (Feb 21, 2010)

HUSKER said:


> :boxer:Speaker Wire VS SPL meters on Android or smartphone:boxer:
> 
> Husker


OH NO! Don't go there.addle: Hehe!


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## HUSKER (Feb 11, 2009)

HUSKER said:


> :boxer:Speaker Wire VS SPL meters on Android or smartphone:boxer:
> 
> Husker





bambino said:


> OH NO! Don't go there.addle: Hehe!



Nobody wins those discussions.

Husker


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## bambino (Feb 21, 2010)

HUSKER said:


> Nobody wins those discussions.
> 
> Husker


Ahh! the winner is always in the mind of the beholder. LOL!:heehee:


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## fwiler (Mar 5, 2012)

bambino said:


> Ahh! the winner is always in the mind of the beholder. LOL!:heehee:


Finally! I win!!!


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