Radio Shack SPL Meter Use [Archive] - Audio & Video Forums

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poneal
12-21-2003, 06:05 PM
Sup all, I just purchased a radio shack spl meter and adjusted my system. At first i just turned on the receiver to my normal listening level and then sent pink noise from my receiver through the speakers and looked at the db level on the meter. It read about 55 so i adjusted them all to 55. Now i started reading on the web about using 75 or 80 as the reference for setting the speakers, so I went back and done it again. The problem is that using 75db as the reference, the volume on cds, etc at this level is overwhelming loud. So i got to thinking, maybe thats what they intended, u know to get the level right and then turn the receiver down to the normal listening level. What do you guys have to say. Is either way right or is one better than the other? Any help appreciated. Thanks, Paul.

F1
12-22-2003, 05:55 AM
I'm wondering, there are quite a few people here advocating to use an SPL meter but there's no response so far. Maybe they are busy this time...:) I never use one myself but just now I read a recent thread about DPLII and Jim Clark pointed this following link that also contains SPL calibration, which may be useful. For your case, my guess is that as long as all speakers producing the same dB then you are set. Good luck.
http://www.hometheaterhifi.com/volume_8_1/dolby-prologic2-3-2001.html

yakkosmurf
12-22-2003, 06:46 AM
I personally haven't ever set mine as low as 55 db. Why are your CD's louder after calibrating at a higher level? Just because you turn the volume up that much to calibrate it, doesn't mean you have to play the CDs and movies at that same volume!!! I typically calibrate mine to around 70 db. Then I set the volume for each movie to whatever level I fell like listening to it. CDs are the same way.

I do have another suggestion. That would be to stop using the pink noise generator on your receiver. My experience has been that it's not a good calibration tool. You should look at buying a calibration disc to run on your DVD player for setup. When I first bought my system, I tried calibrating it with the SPL meter and the built in tone generator. A few weeks later, I got a calibration disc and did it again. You'd be surprised how much different your calibration results on when you use a disc. Using a disc takes into account any differences in the DVD player, cables, but most importantly, your decoder. I have even found that I get differences when calibrating it to DD5.1 verses DTS.

Hope that helps.

JDaniel
12-22-2003, 07:00 AM
I'm no expert here, but I own a Rad Shack analog meter and the Sound & Vision Calibration disc, and have calibrated my system numerous times. The Dolby Reference level is just that - a reference. Dolby Reference level is usually too loud for sustained listening. I calibrated my system at 75 db, then turned it down to what's comfortable for me. I honestly don't think it matters whether 55 or 65 or 75db is used, so long as the speakers are calibrated the same.

The nice thing about the S&V calibration disc is that they use the exact same SPL meter, and give a thorough video tutorial on how to use it and calibrate your system. The trickiest part is calibrating the sub - much harder to do than the main speakers. And if you haven't done a video calibration on your TV, I'd highly recommend doing so. I honestly believe calibrating my system is one of the two best tweaks that I have done to mine (with the other being matching speakers up front - mains + center).

JD

poneal
12-22-2003, 09:02 AM
Thanks for the replys. If I buy one of those calibration DVDs, which tone did you use for calibration? Did you use all of them and then take the average? Is there a set one that it says to use? Also, I think JDaniel is correct. The settings pretty much came out the same way on 55 as did 75, so this leads me to believe that it really doesnt matter what db you use for calibration. An interesting note, after I set the reference to 55db which was about -20 on my receiver, I measured some radio material at -20. I switched the meter to A and fast and at -20 the meter was averaging about 65db. So i am curious as to what tone/frequecy the receiver uses to send pink noise, since the overall db level was about 10db higher than measured with the spl meter. Again, thanks for all your replies. Paul.

yakkosmurf
12-22-2003, 09:37 AM
[QUOTE=poneal]Thanks for the replys. If I buy one of those calibration DVDs, which tone did you use for calibration? Did you use all of them and then take the average? Is there a set one that it says to use? [QUOTE]
I set mine up with the DTS calibration. After a while, I tried it with the DD calibration, just to see the difference. There wasn't that big of a difference, but it wasn't exactly the same. Personally, I've preferred using the DTS settings because that's what I listen to most often. That might be a good guideline for you as well. The difference is only a decibel or two (for me).

recoveryone
12-22-2003, 11:18 AM
Sup all, I just purchased a radio shack spl meter and adjusted my system. At first i just turned on the receiver to my normal listening level and then sent pink noise from my receiver through the speakers and looked at the db level on the meter. It read about 55 so i adjusted them all to 55. Now i started reading on the web about using 75 or 80 as the reference for setting the speakers, so I went back and done it again. The problem is that using 75db as the reference, the volume on cds, etc at this level is overwhelming loud. So i got to thinking, maybe thats what they intended, u know to get the level right and then turn the receiver down to the normal listening level. What do you guys have to say. Is either way right or is one better than the other? Any help appreciated. Thanks, Paul.

I use the RS meter to set and check my system at least twice a year, and the 75db is just a standard set by the lab boys. But what most people forget to adjust for it that all of your equipment needs to be connect with the same type of line..IE Digital or Regular RCA. If your CD is analog L/R it will not calabrate them same as your DVD with digital input. And that is why some people get different sound quality from their CD player and DVD player. I just got a new HDTV Tuner and have both analog L/R and Digital input from it and the sound is like night and day from the analog and the digital. I get full 5.1 from the ABC with digital HD programing and Stereo surround from PBS and NBC. From analog I would get Stereo processed by my amp in DPL to get surround sound. The Meter is a good tool to have, but you need to make sure all things are equal when testing or you may be disappointed with the results.

poneal
12-22-2003, 01:09 PM
Thanks, I was not aware that each piece had to be calibrated. Does that mean you need a calibration CD and a calibration DVD? Or is the DVD one in PCM so that I can use it for both? Thanks, Paul.

Woochifer
12-22-2003, 02:09 PM
The only reason not to use a level as low as 55 db would have to do with background noise. At 55 db, it's easy for everyday household sounds like heating vents or street noise to overly influence the reading that you get on the meter. As others have pointed out, you don't have to listen at 75 db if it's too loud.

And on your latest inquiry, you only need to set the channel balances for your receiver. Some receivers have separate DSP settings for different formats, like the delay timing. But, even if you need to set the surround levels separately for DD and DTS, you only need to identify the level adjustments and apply them uniformly for all formats.

recoveryone
12-23-2003, 06:32 AM
Thanks, I was not aware that each piece had to be calibrated. Does that mean you need a calibration CD and a calibration DVD? Or is the DVD one in PCM so that I can use it for both? Thanks, Paul.

Most receivers have a pink noise signal and that can be used to calibrate your different units...(CD/DVD/TV) it covers all of your systems. A calibration disk can and will fine tune more for the DVD (more on the pic side), but can be use to test your own pink noise setup

_Luke1_
12-23-2003, 07:14 AM
Is that after calibration, I prefer a bit more rear effect for movies. I've bumped the rears a bit louder, adjusting a couple of times until I got my preferred setting BY EAR and not by using the SPL meter. My point is that perfect SPL calibrations and real-world satisfaction may be two different things so don't be afraid to make adjustments without the meter as well.

I don't know how involved you've gotten, but the Stryke bass test tone CD is excellent for sub calibration and while I haven't looked at the site recently I heard they were coming out with a new disk with even more tones. While I have no comparison to any other disks, the S&V also helped me out as well.

yakkosmurf
12-23-2003, 09:59 AM
That does bring up a good point. After all is said and done, you have to like the way it sounds. I've changed settings a little from time to time on different movies. Different sound engineers have different preferences, and they mix things differently. Some of them, I'm not too fond of. Therefore, I make some adjustments to make the recording sound more like I want it to.

poneal
12-23-2003, 02:53 PM
Very good points all. In fact the SPL meter has me setting my surrounds to -3. Thats because they are mounted on the back wall and my couch is also on the back wall. While this sounds good for that position, it doesnt do much for the other 90% of the room forward. I may just bump them puppies up to -1 or 0db and see how that sounds. Thanks, Paul.