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post #1 of 28 Old 08-26-2013, 04:27 PM - Thread Starter
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Anyone know how to use the SPL meter for measuring subwoofer?

I am using the SPL meter with a needle (analog) and not a digital. I have the Range set to "70 dB". I have the Weighting set to "C" and I have the Response set to "Slow".

I was able to measure at 75 dB for all my speakers. But when it come to measure the subwoofer, the needle keeps on bouncing at 75 dB and even higher. Measuring the subwoofer is a little more difficult than I thought.

I guess I don't know where the needle should hit to get 75 dB? When the white noise or the rumbling noise (MCACC Calibration) is coming out of the subwoofer, I tried to get it at 75 dB but the needle keeps on bouncing over 6+ dB on the SPL meter.

It's kind of hard to explain. The needle seems to stay at 75 dB but if you wait a little longer, the needle will bounce pass the 6+ dB on the SPL meter. It's difficult to read because the needle will not stay at 75 dB. It just stay at 75 dB for a short seconds and the needle will bounce way pass the 6+ dB.

It's pretty hard to get an accurate reading using the SPL meter for subwoofer.


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post #2 of 28 Old 08-26-2013, 04:32 PM
 
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A recommendation, lose the needle and go digital.

This is the sound meter I'm partial too and yes, of the several sound meters I have and have used, one is a well used RS, digital sound meter.
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post #3 of 28 Old 08-26-2013, 04:49 PM
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I have somewhat the same problem to a degree with the digital meter I use also. I get a 1-2 dB flexuation. My suggestion is to just do the best you can for a reality check and adjust from there.

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post #4 of 28 Old 08-26-2013, 04:54 PM
 
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Quote:
Originally Posted by steve nn View Post

I have somewhat the same problem to a degree with the digital meter I use also. I get a 1-2 dB flexuation. My suggestion is to just do the best you can for a reality check and adjust from there.

^...+1
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post #5 of 28 Old 08-26-2013, 04:59 PM - Thread Starter
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Can the Digital meter lock the dB reading? Or can the Digital meter do an estimate on the dB and show you the average dB or the next highest dB?

If it can do that, I would buy the Digital SPL meter.
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post #6 of 28 Old 08-26-2013, 05:14 PM
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Your meter is fine. I would suggest go with the first reading before the bounce, the digital does the same to a degree although I can’t speak for the digital option Bee brought up.

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post #7 of 28 Old 08-26-2013, 05:28 PM - Thread Starter
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Thanks guys for your advice!!
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post #8 of 28 Old 10-17-2013, 01:32 AM
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A or C weighted SPL meter is meant for measure noise at at mid range, it is wrong to use it for subwoofer calibration.

Check wiki for C weighting , C weighted mean the lower and higher the frequency , the less sensitive the SPL meter.....if you use a C weight SPL to calibrate the subwoofer, you will set it too loud.

I don't understand why every where in internet , I see expert recommend using SPL meter to calibrate subwoofer....

confused.gif

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post #9 of 28 Old 10-17-2013, 05:22 AM
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Quote:
Originally Posted by mantaraydesign View Post

the needle keeps on bouncing over 6+ dB on the SPL meter.
That's because the level with a pink or white noise source isn't constant. If you were to watch it on an RTA you'd see each individual frequency level is constantly shifting. You can only get a constant level with a sine wave source.
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A or C weighted SPL meter is meant for measure noise at at mid range, it is wrong to use it for subwoofer calibration.
Check wiki for C weighting , C weighted mean the lower and higher the frequency , the less sensitive the SPL meter.....if you use a C weight SPL to calibrate the subwoofer, you will set it too loud.
I don't understand why every where in internet , I see expert recommend using SPL meter to calibrate subwoofer..
If not a meter then what? confused.gif
You don't use 'A' weighting, because that filters out all the lows and highs. 'C' weighting also filters lows and highs, but only below 50Hz and above 5kHz, and that filtering can be compensated for. Unweighted is best, but meters with an unweighted or 'Z' weighting are rare, and expensive.

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post #10 of 28 Old 10-17-2013, 08:37 AM
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Quote:
Originally Posted by Bill Fitzmaurice View Post


If not a meter then what? confused.gif
You don't use 'A' weighting, because that filters out all the lows and highs. 'C' weighting also filters lows and highs, but only below 50Hz and above 5kHz, and that filtering can be compensated for. Unweighted is best, but meters with an unweighted or 'Z' weighting are rare, and expensive.

Wrong measurement tools give wrong result, that is a facts....



C weighted filter not only affect below 50 Hz, all the bass below 100 Hz is affected if you look at the curve line.....worse if the calibration is using pink noise , because the C weighted SPL is just picking up the AVERAGE noise below the low pass crossover frequency from the subwoofer, and as we can see since the SPL meter lowest octave is much less sensitive, the end result will be we need to turn the sub woofer MUCH louder to reach the ref SPL.


Solution? Simple , get a USB measurement mic with a notebook....

Room acoustic treatment is importance.....
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post #11 of 28 Old 10-17-2013, 12:09 PM
 
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Quote:
Originally Posted by joamonte View Post

Solution? Simple , get a USB measurement mic with a notebook....

Not sure where you're coming from.

With the AVR's subwoofer levels set to zero, using AVR provided pink noise, the calibrated, type 2 sound meter is used to individually gain match each subwoofer's output. From there, using each EQ's provided microphone, Anti-Mode and Audyssey MultEQ XT (will upgrade to a XT32 AVR as soon as possible) are run so they can do their magic. After the two EQ programs have done their stuff, a measuring microphone is used in concert with REW to measure and season the output to taste.

Don't know how things can get any better.

...confused.gif

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post #12 of 28 Old 10-17-2013, 06:31 PM
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Quote:
Originally Posted by BeeMan458 View Post

Not sure where you're coming from.

With the AVR's subwoofer levels set to zero, using AVR provided pink noise, the calibrated, type 2 sound meter is used to individually gain match each subwoofer's output. From there, using each EQ's provided microphone, Anti-Mode and Audyssey MultEQ XT (will upgrade to a XT32 AVR as soon as possible) are run so they can do their magic. After the two EQ programs have done their stuff, a measuring microphone is used in concert with REW to measure and season the output to taste.

Don't know how things can get any better.

...confused.gif

-

Friend , if you really depending on the auto calibration thing on AVR to do calibration, I hope good luck on you, I never able to get the setting right with any AVR auto calibration so far.....

biggrin.gif

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post #13 of 28 Old 10-17-2013, 06:39 PM
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Quote:
Originally Posted by BeeMan458 View Post

Not sure where you're coming from.


-

BTW the USB measurement mic thing is refer to the question of last poster mention that "Z weighted SPL meter is rare and expensive", a calibrated USB measurement mic with some cable and free software like REW should cost less than a branded low end A/C SPL meter....

My point is , A/C SPL meter are not design for sub woofer calibration in the first place, I don't understand why so many internet HT expert still recommend it ......smile.gif

Room acoustic treatment is importance.....
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post #14 of 28 Old 10-18-2013, 07:16 AM
 
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Quote:
Originally Posted by joamonte View Post

Friend , if you really depending on the auto calibration thing on AVR to do calibration, I hope good luck on you, I never able to get the setting right with any AVR auto calibration so far.....

biggrin.gif

Thanks! I use a separate calibrator tool for calibrating our sound meters. We have three of them. biggrin.gif
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post #15 of 28 Old 10-18-2013, 07:19 AM
 
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Quote:
Originally Posted by joamonte View Post

..... I don't understand why so many internet HT expert still recommend it ......smile.gif

I only qualify as an incompetent old fool. I use the sound meter to gain match subwoofer output before running the EQ programs and use it to measure the room's acoustics in various locations. Sometimes I like to relax, go outside and use the sound meter to measure the sound of the wind.

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post #16 of 28 Old 10-18-2013, 11:51 AM
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You might want to pick up calibrators for LF and HF as well as the single-point (1 kHz) measurement. Or just spend the $100 and get the calibrated USB mic as previously suggested. These days I suspect few have or need a $1200 earthworks measurement mic with a nice personalized calibration curve, but I have had mine for years so can blame it on my youth. smile.gif

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post #17 of 28 Old 10-18-2013, 06:26 PM
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For example

http://www.daytonaudio.com/index.php/emm-6-electret-measurement-microphone.html

This one do not even need $100....and it is calibated individually.

This one slightly higher than $100 but it can directly plug into notebook without need of phantom power.

http://www.daytonaudio.com/index.php/test-measurement/umm-6-usb-measurement-microphone.html

Room acoustic treatment is importance.....
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post #18 of 28 Old 10-18-2013, 06:33 PM
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Quote:
Originally Posted by BeeMan458 View Post

I only qualify as an incompetent old fool. I use the sound meter to gain match subwoofer output before running the EQ programs and use it to measure the room's acoustics in various locations. Sometimes I like to relax, go outside and use the sound meter to measure the sound of the wind.

-

Than the measurement you taken is not the true dB SPL of the wind, it is just dB C weighted......because you SPL meter is bandwidth limited but the sound of the wind is full bandwidth.

You need to find a way to limit the bandwidth of the wind , band pass it between 100 Hz to 3 kHz in order to get the slightly more correct true dB SPL of sound of the wind....biggrin.gifbiggrin.gif

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post #19 of 28 Old 10-18-2013, 06:45 PM
 
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Quote:
Originally Posted by joamonte View Post

Than the measurement you taken is not the true dB SPL of the wind, it is just dB C weighted......because you SPL meter is bandwidth limited but the sound of the wind is full bandwidth.

You need to find a way to limit the bandwidth of the wind , band pass it between 100 Hz to 3 kHz in order to get the slightly more correct true dB SPL of sound of the wind....biggrin.gifbiggrin.gif

When listening to the wind, I use "A" weighting. confused.gif I'm clueless what the frequency response range of the wind is. All I know, the wind is outside and where we live, one can hear the wind coming, long before seeing the tree tops move.
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post #20 of 28 Old 10-18-2013, 08:04 PM
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If you had your laptop/usb mic you could see the frequency response of the wind as well as the spl !

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post #21 of 28 Old 10-19-2013, 07:25 AM
 
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If you had your laptop/usb mic you could see the frequency response of the wind as well as the spl !

Great idea but I'm a desktop PC. frown.gif
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post #22 of 28 Old 10-19-2013, 01:26 PM
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Quote:
Originally Posted by BeeMan458 View Post

Quote:
Originally Posted by lovinthehd View Post

If you had your laptop/usb mic you could see the frequency response of the wind as well as the spl !

Great idea but I'm a desktop PC. frown.gif

That would make it more difficult....haven't had a desktop at home in years.

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post #23 of 28 Old 10-19-2013, 01:51 PM
 
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That would make it more difficult....haven't had a desktop at home in years.

It's outdated/antiquated and I know that I'm probably the only person within a hundred miles that still has a desktop but I love my desktop PC because I can easily add and change boards, drives and memory. Both the wife and son have and use laptops.

When our current desktop fails, I may break with my old habits and go with a laptop......this as everybody is going with tablets. tongue.gif

(behind the curve? Hell, the curve ran me over years ago)

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post #24 of 28 Old 10-19-2013, 03:39 PM
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Quote:
Originally Posted by BeeMan458 View Post

It's outdated/antiquated and I know that I'm probably the only person within a hundred miles that still has a desktop but I love my desktop PC because I can easily add and change boards, drives and memory. Both the wife and son have and use laptops.

When our current desktop fails, I may break with my old habits and go with a laptop......this as everybody is going with tablets. tongue.gif

(behind the curve? Hell, the curve ran me over years ago)

-

If I ever break down and buy a lap it’ll be for wind/calibration basically, except for when I travel or something. I really like the old style PC, my own little space. smile.gif
I tried a friends tablet on a trip, it worked, but I found it quite odd being a old dog.. no mouse! how can we resist change? By the time we get a tablet it'll be antiquated and we'll need to move on again. eek.gif

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post #25 of 28 Old 10-19-2013, 05:02 PM
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LOL no, am not even a smart phone kinda guy let alone tablet. I have used laptops for many many years and I like being wherever I want to be and be able to use it, whether that's in the living room, kitchen, bedroom, etc or on the road (which I've done quite a bit of since laptops became reasonably powerful/fast). I did get used to a touch pad, and prefer it to a mouse too. If I didn't have a work pc for the last few years at the office I probably wouldn't even be able to use a mouse again. Let alone a touch screen; I don't have any devices that have one. Old dog definitely is me.

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post #26 of 28 Old 10-19-2013, 05:29 PM
 
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By the time we get a tablet it'll be antiquated and we'll need to move on again. eek.gif

My guess, soon we'll be using heads-up technology and we'll put little gizmos on our fingers and look like idiots tapping away in the air, much like we all looked when we first started using bluetooth ear pieces with our cellphones.
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post #27 of 28 Old 10-19-2013, 06:49 PM
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Quote:
Originally Posted by BeeMan458 View Post

My guess, soon we'll be using heads-up technology and we'll put little gizmos on our fingers and look like idiots tapping away in the air, much like we all looked when we first started using bluetooth ear pieces with our cellphones.

biggrin.gif I never did like that look. At first I thought they were talking to themselves until they turned their head. redface.gif now I know.

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post #28 of 28 Old 10-20-2013, 05:18 AM
 
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Ya gotta love technology. If anything, it's makes for some excellent entertainment. It just so darn expensive trying to keep up with the fast moving upgrade curve and trying to stay on top of the next, newest and greatest operating system interface kills you as your brain gets older.
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