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SPL Meter

Hi

Happy new year !

I was thinking of doing some tests and determine at which sound level I'm listening to my music at. Keep in mind that I'm a headphone user, I mostly never use speakers.

Now, I know it can also be calculated if you know the impedance, sensibility of your headphone.

So, does any of you know some good, affordable SPL meters for home use ?

I know there's a topic about this already http://www.hydrogenaud.io/forums/index.php?showtopic=105095 but I'd prefer using an SPL meter since I don't have my analog multimeter anymore. I used it to work with the coiled resistances at work.

Thanks !

Alan


SPL Meter

Reply #2
Hi

Happy new year !

I was thinking of doing some tests and determine at which sound level I'm listening to my music at. Keep in mind that I'm a headphone user, I mostly never use speakers.

Now, I know it can also be calculated if you know the impedance, sensibility of your headphone.

So, does any of you know some good, affordable SPL meters for home use ?


Even though I have at least 3 SPL meters kicking around the house, I think your money is better invested in a good USB measurement mic.  Probably the best choice is this one:

MiniDSP Umic link

Dayton Audio UMM 6

(Pretty much the same mic from two different retailers - also available on Amazon)

This device works with just about any Desktop or Laptop computer's USB port.

The software needed is free downloads - with several choices including:

Room Eq Wizard

Holme Impulse

Parts Express also has an external measurement-grade mic for use with Smart Phone apps.  This is a good idea because a lot of smart phones have relatively high frequency internal low pass filters on their built-in mics in the interest of noise rejection and intelligibility.

SPL Meter

Reply #3
If you already have a smartphone like a great many people, the Dayton IMM-6 mic and AudioTool software will set you back around $25.



cheers,

AJ
Loudspeaker manufacturer

SPL Meter

Reply #4
The question is:
a) how accurate / what class do you need
b) how much money do you want to spend
"I hear it when I see it."

SPL Meter

Reply #5
Sorry to ''ressurrect'' the thread

Arny: The mic looks nice, and would let me measure (via the software) other characteristics as well.

xnor: I guess 100 $CA max. As for precision, something like +/- 1,5 or 2 dBs.

SPL Meter

Reply #6
Sorry to ''ressurrect'' the thread

Arny: The mic looks nice, and would let me measure (via the software) other characteristics as well.

xnor: I guess 100 $CA max. As for precision, something like +/- 1,5 or 2 dBs.


The weak spot in any of these products are the electret microphones, which are great when they work well, but are prone to lose their built in electrostatic charge and a lot of their sensitivity with it.  About 1/3 of the six or so Beheringer ECM 8000s I've bought over the years have lost up to 10 dB of their sensitivity. I've experienced this with other electret mic  products as well.

The solution is to have a microphone calibrator. They are far more resistant to this sort of thing and can be found on eBay. They are basically a 1 KHz signal generator, a small power amp and a small speaker in a handy package, and can be had for about $100 on eBay. They are inherently resistant to this sort of problem.

$140 Microphone Calibrator

The irony is that you can buy a couple-three measurement mics for about the same price and bet that they won't all  fail on you!  Needless to say, I've gone down both roads, accumulating at least 3 SPL meters, about six measurement mics and the mic calibrator over the years... ;-)

SPL Meter

Reply #7
Neither of those two mics are available in Yurp. Not without a lot of customs hassle anyway.

Any suggestions which of these would do the job most economically?

Yurpeen MMs


SPL Meter

Reply #9
If you already have a smartphone like a great many people, the Dayton IMM-6 mic and AudioTool software will set you back around $25.

... ... ...


Thanks. I just ordered one from Amazon.com. Delivery to India at standard delivery rate will take a while but I'm not in a hurry.
The most important audio cables are the ones in the brain

SPL Meter

Reply #10
Quote
The weak spot in any of these products are the electret microphones, which are great when they work well, but are prone to lose their built in electrostatic charge and a lot of their sensitivity with it. About 1/3 of the six or so Beheringer ECM 8000s I've bought over the years have lost up to 10 dB of their sensitivity. I've experienced this with other electret mic products as well.
Interesting!!!  I've often wondered what "permanently charged" meant, and how in the world that could even be possible!

SPL Meter

Reply #11
The weak spot in any of these products are the electret microphones, which are great when they work well, but are prone to lose their built in electrostatic charge and a lot of their sensitivity with it.  About 1/3 of the six or so Beheringer ECM 8000s I've bought over the years have lost up to 10 dB of their sensitivity. I've experienced this with other electret mic  products as well.

Probably a dumb question, but they lose their charge with use, or just with time, or does use accelerate the discharge?

SPL Meter

Reply #12
The weak spot in any of these products are the electret microphones, which are great when they work well, but are prone to lose their built in electrostatic charge and a lot of their sensitivity with it.  About 1/3 of the six or so Beheringer ECM 8000s I've bought over the years have lost up to 10 dB of their sensitivity. I've experienced this with other electret mic  products as well.

Probably a dumb question, but they lose their charge with use, or just with time, or does use accelerate the discharge?


Form what I have gathered, high temperature is the primary culprit, along with humidity.

SPL Meter

Reply #13
Probably a dumb question, but they lose their charge with use, or just with time, or does use accelerate the discharge?
That's no dumb question. Famous measurement microphone manufacturer Brüel & Kjær offers 200V and pre-polarized models and explains aging as follows:
Quote
The sensitivity of any microphone changes slowly but permanently over a long period of time for two reasons.
Firstly, relaxation of the diaphragm tension increases the sensitivity. This process is influenced by the external environment, e.g. temperature.
Secondly, loss of charge from the charge-carrying (electret) material reduces the sensitivity. The two processes work in opposition, but normally the effect of decreased diaphragm tension is dominant.
Brüel & Kjær has minimized this problem by artificial aging during production. For Type 4155 this stability coefficient is better than 1 dB for 40 minutes at 150°C (typically 3 - 10 times better). The long-term stability is highly temperature-dependent and improves markedly as the temperature decreases. Extrapolating the stability-temperature curve to room temperature gives a stability of approximately 1 dB in 400 years.
(source)
These professional microphones are very expensive. Arny's Behringer mics are apparently less reliable over time. Needless (?) to say that periodic calibration is always required to obtain accurate measurements. Arny, is it just sensitivity that changes, or does frequency response change too ?

SPL Meter

Reply #14
Quote
The long-term stability is highly temperature-dependent and improves markedly as the temperature decreases. Extrapolating the stability-temperature curve to room temperature gives a stability of approximately 1 dB in 400 years.


...or ~ 10 dB in under a year or so that summer you left the mic in your car's glovebox, parked in the sun, as you took a lunch break between recording sessions, etc.... DOH!  [just a joke]


SPL Meter

Reply #16
Arny's Behringer mics are apparently less reliable over time.


Thing is the Behringers are just representative of the whole class of mics. It is probable that a lot of the capsules come out of the same factory.  Call it $75 measurement mic syndrome, or what you will.

Quote
Needless (?) to say that periodic calibration is always required to obtain accurate measurements. Arny, is it just sensitivity that changes, or does frequency response change too ?


The frequency response remains pretty much the same as the sensitivity goes down.

SPL Meter

Reply #17
I've ordered the Dayton IMM-6 because I'm interested in noting the sound levels of over-amplified "acoustic" concerts that I attend. Of course, for comparison rather than measurement, precision is not important: maybe I'm just buying a new toy. At the cost, that's fine by me even if I am --- and most of my audio purchases come under that heading, usually at vastly more cost anyhow.

I wonder if this "measurement" mic, to be used with an android phone and Audio Tools, which I already have, would be any good for recording music. Are the qualities of a measurement mic different to those of a recording mic?

Anyway, I may try. Just for the experience. I'm not keen on recording live concerts that I attend because I don't like having the technology taking my mind off the music, and I never owned  anything that, to my ears, made a worth-listening-to recording anyway.
The most important audio cables are the ones in the brain

SPL Meter

Reply #18
A bit late here, but smartphones' built-in mics seem to work surprisingly well - "surprisingly" of course depending on your prior expectations - with the right app and the right offset applied:
http://blogs.cdc.gov/niosh-science-blog/20.../09/sound-apps/ / http://www.cdc.gov/niosh/surveyreports/pdfs/349-12a.pdfhttp://scitation.aip.org/content/asa/journ....1121/1.4865269
- notice how iPhone measurements are way more consistent (same hardware), one needs to apply quite some offset with the four Android phones tested.

and (iPhone): http://www.tinnitustalk.com/attachments/fa...af2012-pdf.402/
High Voltage socket-nose-avatar

SPL Meter

Reply #19
Are the qualities of a measurement mic different to those of a recording mic?


Yes and no. The most common microphone type for measurements is an omnidirectional mic, and the most common microphone type for recording is a cardioid (unidirectional) mic.

A lot of portable digital recorders come with dual omnidirectional mics, but its not clear to me how much that choice is driven by costs.  A lot of pretty good sounding recordings have been made with them, but they have strong inherent limits.

Cheap omnis can be very good and small.  Directional mics are far more complex and miniaturizing them can impact their performance and necessarily makes them more costly to build.

SPL Meter

Reply #20
I have the mic now. Thank you for the advice. Time to experiment
The most important audio cables are the ones in the brain

SPL Meter

Reply #21
It will be in mono, so for speech and Heavy Metal you should be ok.
Loudspeaker manufacturer

 

SPL Meter

Reply #22
It will be in mono, so for speech and Heavy Metal you should be ok.


Oh yes... (Doh!) but no, that wouldn't worry me and, if I recorded any live music, it would be South Indian Classical (Carnatic) because that is what I mostly see performed live.
The most important audio cables are the ones in the brain

 
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