SPL Meter ?

[Lightning Steve]

More questions!!
I am learning a lot here and thanks for all the help and patients!!

Have been reading and it looks like the tool for HT set up is a SPL meter. Have some questions about this that I didn't run across in my searches.

-Is a SPL meter useful for a beginner Audioholic (I think so). What I'm wondering is it going to be useful more than once (I'm not going to be redoing my HT area to often). Once the room is set up is that it for it's usefulness until changes or a new HT setup?

-Have read over several (LOTS) of posts and roughly understand the need/use of the meter but just how do you use it? Is it a "directional" type of thing, you "point" it at a specific speaker and take a reading, ultimately adjusting all speakers to an equal level. Or do it just take an "area" reading?

-Is the SPL meter relatively easy to use for a beginner or will I require a four year Audio engineering course?

Thanks Steve

[mazersteven]

-Is a SPL meter useful for a beginner Audioholic (I think so). What I'm wondering is it going to be useful more than once (I'm not going to be redoing my HT area to often). Once the room is set up is that it for it's usefulness until changes or a new HT setup?

-Have read over several (LOTS) of posts and roughly understand the need/use of the meter but just how do you use it? Is it a "directional" type of thing, you "point" it at a specific speaker and take a reading, ultimately adjusting all speakers to an equal level. Or do it just take an "area" reading?

-Is the SPL meter relatively easy to use for a beginner or will I require a four year Audio engineering course?

Thanks Steve

1) The SPL meter is a must have for any HT (beginner, or guru).
2) It will be useful many times. Some like to tweak their systems constantly. Some just like to set it, and leave it. I have heard many say you should re-calibrate your system once every 6 months or so.
3) You will run test tones throughout each individual speaker through your receiver.
4) Easy to use.

[3db]

1) The SPL meter is a must have for any HT (beginner, or guru).
2) It will be useful many times. Some like to tweak their systems constantly. Some just like to set it, and leave it. I have heard many say you should re-calibrate your system once every 6 months or so.
3) You will run test tones throughout each individual speaker through your receiver.
4) Easy to use.

Hey Maze,

How many times have you recalibrated your system? I do it twice a year only because my inlaw who is hard of hearing needs the center channel turned up and the bass of the sub turned down and I forgot what my original settings were. But as far as positioninng and having to recalibrate, its all good.

[mazersteven]

Hey Maze,

How many times have you recalibrated your system? I do it twice a year only because my inlaw who is hard of hearing needs the center channel turned up and the bass of the sub turned down and I forgot what my original settings were. But as far as positioninng and having to recalibrate, its all good.

In the 2 1/2 years of so that I have had my system. I have calibrated it about 4-5 times. I haven't touched it since May, since IMO it sound great right now.

[Halon451]

Have read over several (LOTS) of posts and roughly understand the need/use of the meter but just how do you use it? Is it a "directional" type of thing, you "point" it at a specific speaker and take a reading, ultimately adjusting all speakers to an equal level. Or do it just take an "area" reading?

Thanks Steve

Steve - most folks here will probably give you the same advice. Find your normal listening position (i.e., the couch, chair, wherever you intend to do most of your listening). It is best to attach the meter to a tripod (typical camera tripod) to ensure it is perfectly stationary. You will want to point the SPL meter's mic towards to ceiling, as it will be taking sound levels from each direction of the room in a typical surround sound setting.

Next, adjust your system's volume to the normal listening level (what you would normally have it at, during regular viewing/listening). Enter your Receiver's speaker level check (as found in your user's manual) - this will generate the pink noise from each speaker. You will want to find the reference level on the SPL meter that best aligns the sound level within the center of the range, and use that henceforth as your reference. Mine has ranges in 10db increments, at 20 dB range on each one, plus or minus.

There is no trick to this - it's ridiculously easy. Go through each speakers level check, and calibrate it to the same level (adjusting each speaker up or down), until all of the SPL meter readings are the same.

Oh, and you want to ensure you are on 'C' weighting, with a slow response.

Some people like to run their subwoofer a little hot (i.e., 5 dB or so above the reference level for added impact), but this is entirely up to you, and your own preferences.

I hope this helps. :D

[AcuDefTechGuy]

-Is the SPL meter relatively easy to use for a beginner or will I require a four year Audio engineering course?



Steve, please buy this:

http://www.bhphotovideo.com/c/product/333306-REG/Galaxy_Audio_CM_130_CM_130_CHECK_MATE_.html

You cannot post anymore at Audioholics until you have this!

Didn't you get the Memo?:D

[supervij]

I find the SPL meter is very easy to use when it comes to all speakers but the sub. Whenever I try to level-match the sub, the needle is all over the place -- a few seconds it's bang on, the next few seconds it's six decibels higher, the next few seconds it's four decibels lower . . . the needle ricochets all over the place. How do I calibrate when the needle does that?

cheers,
supervij

[AcuDefTechGuy]

I find the SPL meter is very easy to use when it comes to all speakers but the sub. Whenever I try to level-match the sub, the needle is all over the place -- a few seconds it's bang on, the next few seconds it's six decibels higher, the next few seconds it's four decibels lower . . . the needle ricochets all over the place. How do I calibrate when the needle does that?

cheers,
supervij

Same here, until I got the Galaxy Audio DIGITAL SPL meter!
Makes level-matching SO SO EASY!

BTW, you did set to SLOW (instead of FAST) & dB-C (instead of dB-A), right?:)

[Guangui]

Same problem here. Threw the $30.00 analog in my forgotten tools box, and purchased another one (http://www.testequipmentdepot.com/extech/soundmeters/407730.htm). It is about $20.00 more expensive than Radio Shack's Digital SPL or Galaxy, but worth every penny, extremely accurate, and does not jump all over the place.

[Halon451]

My Radioshack digital SPL meter is pretty steady, I haven't had that problem at all. It may oscillate +/- 1 dB or so, but after a few seconds it will settle in and take hold on a specific reading.

[AcuDefTechGuy]

Same problem here. Threw the $30.00 analog in my forgotten tools box, and purchased another one (http://www.testequipmentdepot.com/extech/soundmeters/407730.htm). It is about $20.00 more expensive than Radio Shack's Digital SPL or Galaxy, but worth every penny, extremely accurate, and does not jump all over the place.

That is nice. Is it really 0.1dB resolution? The $60 Galaxy Digital SPL is 0.5dB resolution.

[Guangui]

That is nice. Is it really 0.1dB resolution? The $60 Galaxy Digital SPL is 0.5dB resolution.

Yes it is! My cousin is a car audio freak, and recommended it as it is what he uses when judging car audio competition. Bought it, and it is really very accurate, more than what I need, but for picky people who like to mess with crossovers and like to say they have a supernatural ear, this is a great tool to have.

[AcuDefTechGuy]

Yes it is! My cousin is a car audio freak, and recommended it as it is what he uses when judging car audio competition. Bought it, and it is really very accurate, more than what I need, but for picky people who like to mess with crossovers and like to say they have a supernatural ear, this is a great tool to have.

Damn, I hate being cheap sometimes!
I spend all this money, but I can't pay an extra $20 for the 0.1dB resolution, instead of 0.5dB.
Thanks a lot!
I hate myself now.:D

[supervij]

Same here, until I got the Galaxy Audio DIGITAL SPL meter!
Makes level-matching SO SO EASY!

BTW, you did set to SLOW (instead of FAST) & dB-C (instead of dB-A), right?:)
Yup, and yup. Slow and C. The needle never finally settles down. I don't understand why this happens. Do you think it's due to excessive reflective surfaces?

So you're saying that you had the same problem but that this new GA digital SPL meter can solve this problem? How? Does it work under different principles?

All I know is this problem with "the needle that won't rest" is driving me nuts. I never know where to set the level for my sub. I end up leaving it where YPAO suggests, but who knows if that's accurate?

cheers,
supervij

[Jacksmyname]

When using a meter, should I:
Set the levels first and then run the receiver's setup (RX-V3800) skipping the level check?
Or vice versa?
Thanks!

[ParadigmDawg]

I run the auto-cal and then go back and change the speaker size and crossover and then reset the levels with the SPL at 75db with the master level being "0" .

[Jacksmyname]

Thanks Greg.

[AcuDefTechGuy]

Yup, and yup. Slow and C. The needle never finally settles down. I don't understand why this happens. Do you think it's due to excessive reflective surfaces?

So you're saying that you had the same problem but that this new GA digital SPL meter can solve this problem? How? Does it work under different principles?

All I know is this problem with "the needle that won't rest" is driving me nuts. I never know where to set the level for my sub. I end up leaving it where YPAO suggests, but who knows if that's accurate?

cheers,
supervij

Yeah, I think it is acoustic related. I don't think the digital SPL meter will eliminate this problem. It just makes it easier. When you can actuallly see the numbers go from 74.0 dBC to 74.5 dBC or even between 74dB & 75dB, I just think it's more assuring than just seeing the needle go back and forth. At times I wonder if the needle is going from 70dB to 75dB or what? But with a digital meter, the numbers usually go back and forth in small increments.

Now if you have that $80 digital meter that goes in 0.1dB increment, it would be really assuring if you just see the numbers go from 74.8dB and 75.0 dB!

http://www.testequipmentdepot.com/extech/soundmeters/407730.htm

[AcuDefTechGuy]

I run the auto-cal and then go back and change the speaker size and crossover and then reset the levels with the SPL at 75db with the master level being "0" .

Do you guys usually wear ear plugs or headphones when this 75dBC sound is doing it's business?:)

[ParadigmDawg]

I set my master volume at -15 and then calibrate to 60db so that zero = 75db. I dont want to hear 75db of static;)Do you guys usually wear ear plugs or headphones when this 75dBC sound is doing it's business?:)

[GlocksRock]

I don't, it doesn't bother me at all.

[AcuDefTechGuy]

I set my master volume at -15 and then calibrate to 60db so that zero = 75db. I dont want to hear 75db of static;)

Okay, don't laugh! I may be having a brain-infarction. :D But the SPL meter actually says "60 dBC"?:confused:

[aberkowitz]

Question- when I got my Onkyo 805 (August) I used the Audyssey speaker set up and mic to calibrate my speakers. I actually ran the thing 3 times and wrote down the settings to make sure it came out the same each time (amazingly enough it did!). Would you recommend calibrating on top of that with an SPL meter?

[ParadigmDawg]

Not sure what you mean. Yes if I cal it at 60 it says 60.Okay, don't laugh! I may be having a brain-infarction. :D But the SPL meter actually says "60 dBC"?:confused:

[no. 5]

The needle never finally settles down. I don't understand why this happens. Do you think it's due to excessive reflective surfaces?

I am not certain why it happens, but I have a theory. :eek:

If you watch a spectrum analyzer that has pink noise running through it, and it's not set for peak hold, each frequency band will jump around quite a bit, but if you were to average all the bands that make up the ten octaves we can hear into one measurement it would be a stable measurement, however, a subwoofer doesn't cover ten octavos, it's more likely to cover two or three (or more depending on your sub :D), so I *think* that averaging that smaller bandwidth will result in greater needle deviation from one moment to the next, however, if you add more time to the measurement, it will average the same as the greater bandwidth measurement. But since the typical SPL meeter doesn't have any kind of memory, you'll just need to watch the needle for a little bit and make an assumption as to where the average is.

[Warpdrv]

Question- when I got my Onkyo 805 (August) I used the Audyssey speaker set up and mic to calibrate my speakers. I actually ran the thing 3 times and wrote down the settings to make sure it came out the same each time (amazingly enough it did!). Would you recommend calibrating on top of that with an SPL meter?

I would... I and many people don't tend to put all that much faith in the on board calibration... Its pretty good, but by no means perfect...

Copy down the settings of what your Receiver came up with and measure with SPL to see what differences you come up with.. trial and error..

If your really @nal, like alot of tweakers are, you could get a program like Room EQ Wizard (http://www.hometheatershack.com/forums/downloads-area/19-downloads-page.html) to fully analize your room, but that is pretty involved...

[Erin Hardison]

What are you willing to spend?

If you already have a laptop, for under $150 you can assemble a very nice laptop RTA setup.

All you need is:
Laptop that can run an RTA program
RTA software such as ARTA (you can use the demo for free, which is just as functional as the regular version, but you can't save info), or you can "find" software such as SmaartLive ;)
A mic (http://www.zzounds.com/item--BEHECM8000)
Some sort of sound 'card' to power the mic (http://search.ebay.com/search/search.dll?sofocus=bs&sbrftog=1&maxrecordsreturned=300&frpp=50&from=R10&satitle=mobile+pre+usb&sacat=-1%26catref%3DC6&sargn=-1%26saslc%3D2&sadis=200&fpos=35601&sabfmts=1&saobfmts=insif&ftrt=1&ftrv=1&saprclo=&saprchi=&fsop=1%26fsoo%3D1&fgtp=)
XLR Cable (http://www.zzounds.com/item--WHRMC20).


In total, I spent about $150 shipped for the mic, pre-usb sound card, and xlr cable. If you buy the pre-amp new, you'll spend more. But, being honest, if you're even half way serious about getting a good setup, this will be the best way to go.

Don't forget that you can also do time arrival analysis and all sorts of other stuff.

It's a bit confusing when you set it up, but man, it's worth it. I've used this stuff no telling how many times. Heck, I even pull out the mic & laptop sometimes just to get frequency response of my dogs' barks. lol

Just have fun with it, and learn.


As for placement of the mic, I toyed with this. Below are my results when testing right side, and left side, both individually. AKA: only music from right channel, then only music from left channel, rather than music from both channels. You can see there is a big difference in FR.
At the advice of others here I decided to actually test RTA measurements with the mic facing forward (pointing toward the windshield), and to the sides mimicking my ears (facing the windows).

Left Side:
Ear position
http://i18.photobucket.com/albums/b138/bikinpunk/rta/LeftSideear.jpg

Facing forward:
http://i18.photobucket.com/albums/b138/bikinpunk/rta/LeftSidefacingmicforward.jpg


Right Side:
Ear position:
http://i18.photobucket.com/albums/b138/bikinpunk/rta/RightSideear.jpg

Facing forward:
http://i18.photobucket.com/albums/b138/bikinpunk/rta/RightSidefacingmicforward.jpg


Take these measurements as you wish. I just found it interesting at the difference mic position really does make. Just wanted to share with others for future info.

[supervij]

I am not certain why it happens, but I have a theory. :eek:

If you watch a spectrum analyzer that has pink noise running through it, and it's not set for peak hold, each frequency band will jump around quite a bit, but if you were to average all the bands that make up the ten octaves we can hear into one measurement it would be a stable measurement, however, a subwoofer doesn't cover ten octavos, it's more likely to cover two or three (or more depending on your sub :D), so I *think* that averaging that smaller bandwidth will result in greater needle deviation from one moment to the next, however, if you add more time to the measurement, it will average the same as the greater bandwidth measurement. But since the typical SPL meeter doesn't have any kind of memory, you'll just need to watch the needle for a little bit and make an assumption as to where the average is.
Well, in all honesty, I was getting that glazed-brain thing happening as I read the first bit of your post. Thank the Maker you included that last sentence! Okay, I'll do some averaging. Thanks for the advice. Although figuring out the average will likely be a pain in the asterix on an analog meter, especially when the needle jumps past the given range (i.e., 60-76 dB). :eek:

cheers,
supervij

[no. 5]

Well, in all honesty, I was getting that glazed-brain thing happening as I read the first bit of your post. Thank the Maker you included that last sentence!

LOL, glad to help! :D :D

[AcuDefTechGuy]

Not sure what you mean. Yes if I cal it at 60 it says 60.

Oh, okay, I think I got it.
So what you actually HEAR is 60dB for each channel (SPL meter reads 60dB).

When I do my level-matching, my SPL meter reads 65dB.

But I thought that when you level-match all channels at 75dB, it means that the SPL meter actually reads "75dB"?

[AcuDefTechGuy]

But since the typical SPL meeter doesn't have any kind of memory, you'll just need to watch the needle for a little bit and make an assumption as to where the average is.



So perhaps a digital SPL meter has "memory" and is able to display the "average" reading (Slow Mode = Average Reading)?

[no. 5]

So perhaps a digital SPL meter has "memory" and is able to display the "average" reading (Slow Mode = Average Reading)?

Yep, come to think of it, a digital meter would have to have a memory to effectively have a 'slow response' setting. :)

[ParadigmDawg]

That's how I do it.Yep, come to think of it, a digital meter would have to have a memory to effectively have a 'slow response' setting. :)

[AcuDefTechGuy]

Yep, come to think of it, a digital meter would have to have a memory to effectively have a 'slow response' setting. :)

BINGO!

There you have it, boys: Digital SPL meters are better than Analog meters because Digital meters have a Memory for the Average Reading in the Slow Response Mode.:)

That's why my readings fluctuate from 64.5dB to 65.0dB, instead of from 60dB to 65dB.

[no. 5]

There you have it, boys: Digital SPL meters are better than Analog meters...

Pshaw! Everyone knows analog is more realistic and natural. :p