SPL Meter Calibration (1 Viewer)

[Doug MacGregor]

Just getting ready to calibrate my 18 month old HT with my new RS analog SPL meter.
I have read Vince's primer on the process and I have just one question.
When I set the SPL meter on the tripod at ear level and the viewing position and angle it upwards at 40 degrees, do I point the meter at the various speakers when I play the pink noise and frequency spreads or do I just point it strait forward and leave it there for the duration of the testing?
Thanks.

 

[SteveLeach]

Point it strait forward and leave it there for the duration of the testing. At least that's what I do.

 

[Frank Zimkas]

No, No, No! Read the instructions people! Do I have to come over there and do it for you! Straight up is the way to go. Maybe this will help a bit.

 

[Doug MacGregor]

Thanks Frank.
I read everything I could find, including that article.
There is no reference to "holding it straight up" as you suggested.
Thanks just the same.

 

[Frank Zimkas]

Okay I was wrong, the manual actualy say's that the meter works best when pointed at the source (In my maual it's on pg.11). But as i was told,and I believe it was on this forum, you don't point your ears directly at the source, therefore you should point the meter straight up. If you have the new model, you can look on page 12 under the section titled "Microphone." Here's the new model's manual if anyone needs a copy.

 

[Doug MacGregor]

Thanks again Frank.
I'll do a little experimenting.
After all, that's half the fun, isn't it?
Cheers.

 

[Frank Zimkas]

Sure is, and the other half is upgrading!

 

[douglas-b]

Straight up is how I do it.

 

[Doug MacGregor]

Wow!
What a difference.
Just finished my first calibration go-round.
I can't get over how "off" my settings were.
My Mains have magically re-appeared due to the fact that my Center speaker was turned up too high.
And I didn't realize that my Sub was up way too high too.
I also didn't realize that "reference level" was so high.
I set the meter to 80dB "pointing straight up" and the pink-noise test was almost deafening (not really but it was loud).
At least I know where reference level is now.
Actually I've never had my receiver up that loud before.
(JVC 6010 VBK).
Going to do the frequency spreads next and the fixed frequency tests.
To anyone wondering if calibration is really worth it...
It's indespensible.
Watched Thelma and Louise last night (not my choice) and not the best surround test but...
The part where the cop gets locked in the trunk and Thelma throws the keys away...
I heard them hit the ground just to the left of me!
LOTR next up.
Thanks guys.

 

[ChrisWiggles]

See page 12 of the linked .pdf manual, to see the microphone response.

 

[Bill Blank]

The mic in the RS meter is non-directional so it doesn't really matter where you point it. Straight up s recommended and probably most often used because it doesn't bias the front three speakers as pointing it straight forward could.

Congrats on what appears to be a successful calibration. It's amazing what proper speaker placement, levels, and delay can do for a system. I'm now on to the next step, addressing room problems...

Bill

 

[ChrisWiggles]

Yes it is. See the brochure that was previously linked, and that I was referring to. It shows the response on and off axis.

 

[Bill Blank]

Chris,

From my Radio Shack Sound Level Meter Owner's Manual:

"Microphone - Electret condenser omnidirectional becoming slightly directional with increase in frequency"

So I was wrong in saying it was non-directional, I should have said omnidirectional which means being in or involving all directions. Since he's only "measuring" pink noise to get levels equal (as opposed to taking a frequency response plot) the "slightly directional with increase in frequency" doesn't come into play.

Bill

 

[ChrisWiggles]

It actually would very slightly, but as you will find out with some experimentation it shouldn't make much of a difference at all.