SPL Meter ?

[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. But the SPL meter actually says "60 dBC"?

 

[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. But the SPL meter actually says "60 dBC"?

 

[no. 5]

Thinking out loud...

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.

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 ), 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 to fully analize your room, but that is pretty involved...

 

[ErinH]

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
Some sort of sound 'card' to power the mic
XLR Cable.


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

Facing forward:

Right Side:
Ear position:

Facing forward:

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.

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 ), 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).

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!

 

[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.