New SPL Meter ??????

I recieved a new Radio Shack digital SPL meter as a christmas gift. My question is what is the best way to use it? I understand how it works but in a surround system where should I sit it, what direction should I point it, How loud should I have my system? I need to know what the book does not say. Any ideas would help?

Thanks Again
Lasher

Here's a quick blurb from the 950's manual (page 27) that might get you started.



Once that's all done, set your system volume to a reference listening level (on the 950, that's "00" dB, but other gear will vary -- you might use a test tone on the left or right channel and set the system volume to a point where you get ~75dB). Then run through the test tones and adjust each channel's trim to produce the same reading.

There are also a few threads floating around that look at meter use pretty closely, including a lengthy debate on the merits of meters at all . (Upon briefly re-reading that thread, I had a flashback to my Experimental Techniques II lab in college, and a crazy professor who insisted that proper uncertainty analysis was foolish and that anyone could measure to within 1/64 of an inch with a ruler marked in divisions of 1/8th of an inch. He also swore that he could draw a "perfect" circle or straight line freehand. We were so glad to see him retire.)

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Its my understanding that the analog Radio Shack SPL meter is not very accurate at low frequency's. I recall that the SVS site used to have something about how to check bass response using these meters.

The low frequency response of the RadioShack meter rolls off - I would be almost certain the digital version does the same thing. This does not make either of them less useful for routine calibration duties however. Like I've written many times, motion picture dubbing stages keep one of the RadioShack analog meters handy to check their levels. If it's good enough for them.......

And for those still searching for the ol' RS analog standard, Sears now sells a Craftsman that has the same basic innards but a new face. Not as nice a face as the original, but gets the job done.

http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=03482297000

Gonk,
I just read that whole debate and I can't believe the hot tempers on here sometime I would think considering how much most of us spend on our gear that spending 40 to 50 bucks to make even the slightest improvement would be a no brainer. I've seen plenty of people spend more than that on 1 cable......lol. Why not at least give it a try?

Soundhound,
I like alot of bass to my music and was not planing on using my meter for the sub anyway. I was just wanting to get my front 3 and back 2 even. The dvd I've used to set up my system before is called Ultamate DVD Platnum. I bought it several years ago when I was first getting into HT. Does anyone know if this is a good setup disk to use?

Thanks Again
Lasher

You understand correctly -- and SVS does indeed have a compensation chart .

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gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

Frankly, I would just ignore the subwoofer calibration (which is questionable at best at such low frequencies, in real rooms) and adjust the level to taste. Since the LFE is "synthesized" anyway in motion picture soundtracks, there is no "standard" other than what what sounds best to you.

I sit on the dubbing stage during the mixdown of many films, and what is "standard" during mixdown is probably too mild for what you would want in your home. Just adjust it for what makes you happy.

[This message has been edited by soundhound (edited January 01, 2004).]

Laher, I hope you enjoy your new Christmas gift. I occasionally use my meter just to make sure everything is still calibrated "properly." Originally I set my speaker levels by ear and found I was only off by about 1db per channel but that was enough for me to justify the cost of the meter. I have already played the game of test dvd tones VS 950 generated test tones and finally settled with the 950's tones. Gave up on using the meter to set the sub, even using SVS' chart. Just set the sub to your taste. Have fun with your system.

.

Sears Craftsman makes a very similar SPL meter to the RadioShack analog one, and it probably is made by the same company that made them for RS.

http://www.sears.com/sr/javasr/product.do?BV_SessionID=@@@@1771511359.1073095863@@@@&BV_EngineID=ccjfadckflfidhfcehgcemgdffmdfko.0&vertical=TOOL&pid=03482297000&bidsite=&vertical=T OOL&vertical=TOOL&com.broadvision.session.new=Yes&com.broadvision.session.new=Yes

For LFE, calibration probably is moot.

But for general sub set-up:

If you have any equalization for your sub, the sound meter is a very handy tool for taming peaks. I use my sub for movies and music and had a nasty +12db peak in the mid 30's. I eq'd it out and it is infinitely more listenable. There are correction tables for the low freqs of a Rat Shack meter. You can also use a Bass CD (such as that for mobile audio competition tuning) to generate your tones and plot out your response at the primary listening position.


[This message has been edited by Slee_Stack (edited January 03, 2004).]

To really do it right, you need to use an RTA to see the entire bass range at once. I use Real RTA (www.trueaudio.com) and a calibrated microphone.

This is a plot of my low end from 10Hz to 50Hz using this software and pink noise with 1/24th octave resolution. I don't use any equalization in the low end for several reasons.




[This message has been edited by soundhound (edited January 03, 2004).]

"I don't use any equalization in the low end for several reasons." ...Soundhound

Let me see... umm...no equalization ... why ... could it be ...

because ...

YOU DOM'T NEED ANY?

All that space taken up diplaying that BIG graph just to show a skinny little flat blue line at the top.

Luck dog!!!

Paul


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the 1derful1

Soundhound,
If I'm reading that correctly(and I'm no expert). How do you keep fillings in your mouth

On a more serious note I always thought the best way to tame peaks was to add another sub. I'm looking for a match to mine right now so I can add a 2nd. I've heard alot of real world(read real living rooms) systems and the one's with 2 subs always sounded smoother to me. Any thoughts?

Lasher

Lasher:

Yes you are reading the graph correctly

I guess my graph could be a testament to the theory you've heard - this is a graph of all four of my 18" subs playing at once. Individually the response, while still extremely good, is not quite as flat.

I couldn't say however that more than one sub will automatically give you flatter response in all rooms. Sometimes a single sub will be better in an ideal location in a less-than-ideal room. My room is perfectly symetrical and built from the ground up for this purpose, so that makes a lot of difference.

The best thing to do is to invest in some RTA software, a calibrated microphone and experiment. An RTA is really the only way to sort out all the possibilities since you can see the effects of positioning and such at once and all across the band.

[This message has been edited by soundhound (edited January 03, 2004).]

Lasher - I wasn't being critical of you or anyone else or knocking the RS Analog or digital meters, I have an analog one myself. I was just trying to be helpful.

Soundhound: I was only trying to be helpful in the event Lasher wanted to use the meter to help equalize his system. We aren't all as fortunate as you to have rooms that can be built to minimize sonic defects or have multiple subs and other equipment to address what ever else needs fixing. Most of us even have jobs that are completely unrelated to the things we enjoy, Call me totally jealous if you want.

Gonk: Thanks for posting the actual link.