OT Do I REALLY need a SPL meter?

BillyBoy wrote on 1/10/2005, 3:25 PM
I'm NOT a audiophile! But since I blew $$$$$ on my new home theater system I'm thinking a few more bucks to set it up right won't hurt, but is it over kill for home use?

A SPL (Sound Pressure Level) meter or sometimes called a sound level meter.

Like http://www.tnt-audio.com/clinica/spl-meter_e.html or their analog version.

Do I REALLY need to do this to get the most out of speaker placement, setting DB level and what source of "noise" to set up, pink noise?


winrockpost wrote on 1/10/2005, 3:30 PM
........I'm NOT a audiophile

Sounds to me like your leaning that way :)

Ears, the way to go ,at least for me. I adjust the settings anyway most every flick I watch
Chienworks wrote on 1/10/2005, 3:32 PM
I use a sound meter when setting up a sound reinforcement system on stage in a theatre, just to spot check the house and make sure there are no really bad dead spots. However, these venues are usually 500 to 2500 seat houses with people paying $10 to $40 per ticket and expecting to be able to hear their 5 year old when he whispers his lines. In your living room/den let your ears be your guide. Yes, there probably will be sweet spots and dead spots, but you probably won't even notice them when you pass through them unless you're specifically listening for them. Make sure it sounds good on the overstuffed couch and enjoy.
farss wrote on 1/10/2005, 3:39 PM
Just measuring SPL will tell you very little, after all you can turn the volume up or down and have the readings change. Unless you're looking for dead spots.

What you might be talking about is using a spectrum analyser to measure frequency response so you can correctly set the Eq? To do that you either need 1/3 octave or parametric equalisers in the system.
Basically a waste of time unless you've got very good speakers to start with and you do need very good equalisers otherwise you introduce phase errors as well and the whole thing gets very messy. Probably best to pay someone to with the right gear and knowledge to do this for you.
epirb wrote on 1/10/2005, 4:06 PM
I respectfully disaggre with you farss,
I strongly reccomend BB you pick up an Ovations
It not only has some very usefull Video test patterns for helping calibrate your screen.(unless you want to hire a ISF calibrator, Big $$$ but they'll do it up right).
But the audio portion of the disc is excelent too. Having even the basic levels set properly for ALL speakers incl. surounds and the Sub W makes a big difference! I do alot of this kind of work on yachts, with system that come on the boats or have stufff added. Most times people have the surr. spkrs set way to high, cuz they think it'll make the surround "experience " better...Not!
Phase is important as is Crossover freq settings for the subwoofer.
This disc will by no means calibrate a system as accuratly as what farss is describing , it WILL help you achieve a much better set up , with your equipt. than just winging it.
You can also pick up an inexpensive SPL (you want the analog one) from Radio Shack for about 39 bucks.
Go look at the site and you'll see all the tests for both audio and video.
I use mine 2-3 times a week on systems , and the owners who are not audiophiles even notice a marked difference from before.
farss wrote on 1/10/2005, 4:29 PM
maybe I was being a bit over the top, certainly anything is better than nothing.
I guess what I was talking about is more for the calibration of monitor speakers. I'd also throw in the importance of speaker placement, particulalry for surround systems.
epirb wrote on 1/10/2005, 4:37 PM
True placement is a big part, this disc covers a little of that , but info like Spot has provided b4 like distance from walls, obviously how bright your room is, and even though bass and LFE are nondrectional, proper placement of the sub woofer makes a diiference.
epirb wrote on 1/10/2005, 4:52 PM
another reason this disc is nice is you are setting/calibrating through the audio and video chain.(DVD-RECV(AVR)-SPKRS).
Plus BB, I believe on the unit you bought , all of your video settings and adjustments are input specific, so what you set on one input is only adj. that input's settings. If you bought the Denon with the component output, even though theoreticly the"best way is a connection from the output device to the Monitor, if you send your HDTV cable box into the AVR and your DVD to the AVR then output to the Plasma, you will then cal that input into the monitor and be very happy with the picture.
good quality cables make a diference, dont skimp there either.
As Steve Dahl (An-tony)used to say, you want your picture to look "Niiishhh"(inside Chicago joke)
BillyBoy wrote on 1/10/2005, 5:06 PM
Yep, the monitor allows different setting for each of its inputs. The Denton A/V I got has 3 component in all fed to a single component out, with 1 cox audio and 2 optical. I also ordered a seperate component input card for the monitor just to see going directly from the cable box to the monitor gives a better picture. Another reason I got the Denton is it has a 100Mhz bandwidth for the video side and does a up convert of any composite or S video to component, nice for my old VHS stuff, maybe. Haven't tried it yet.
Spot|DSE wrote on 1/10/2005, 5:25 PM
You should use an SPL meter for setup at least the first time, and using a spectrum analyzer is "good" for a home system, except that flat isn't desirable in a home. Some SA's have curved presets for home setup. You can buy a cheap and quite useable SPL meter for what the daily rental would be, and they're always fun to have around. After about the age of 35-40, it's virtually impossible to set this by ear and be accurate. Ears, like eyesight, start to fall apart for males around the late 30's. This is one reason we EQ music differently, and one reason why chick flicks and more dramatic films are mixed much differently than action flicks and teeny bop flicks.
The disk Eprib mentions is a great one, but if you have Pirates of the Carribean with Johnny Depp, you've got a pretty dang solid calibration tool there, too. Check out the directors xtras. Very sweet stuff, I wish more DVDs had this.
farss wrote on 1/10/2005, 6:23 PM
Excellent movie, got to see it projected at 2K with sound setup by Dolby engineers. Best sound I've ever heard in a cinema and it was a HUGE theatre.
Just made me realise how much c**p we put up with in the average cinema.
It must really bug a lot of guys in the industry who put so much effort into their craft and end up having most of it wasted with poor projection, worn out prints and badly adjusted sound systems.
richard-courtney wrote on 1/10/2005, 8:31 PM
"After about the age of 35-40, it's virtually impossible to set this by ear and be accurate. Ears, like eyesight, start to fall apart for males around the late 30's."

Thanks Spot, now I am really depressed. Is that why I am forced to do post
production work?

We have hired an engineering firm in the past and was worth the money.
Make sure they don't charge a thousand dollars to simply recommend hanging acoustical
drapes. THX certified worth it or just hype?
BillyBoy wrote on 1/10/2005, 8:44 PM
Not to depress anybody but...

The range of hearing gets worse as we age, getting worse faster for men.

For many healthy young persons the range is 20 to 20,000 hertz. People lose their ability to hear high frequency sounds as they get older. A normal middle-aged adult can only hear is in the upper range between 12-14 kilohertz.

Well my hair isn't falling out yet.

Grazie wrote on 1/10/2005, 8:52 PM
Use once? Use to re-calibrate? Move the furniture? . . . .Why not just hire one for that once off necessity. Stupid idea? Yes/no?

riredale wrote on 1/11/2005, 12:14 AM
I found the cheapo Radio Shack meter was useful for setting the surround speakers levels. My ears were nowhere near as accurate as I thought they were.
farss wrote on 1/11/2005, 5:02 AM
I think for levels they'd be fine. But just the type of mics used for full on system calibration are fairly expensive. It really depends on how much you've spent in the first place. If you've spent > $20K on speakers then what's another $1K to get an expert to adjust everything to the room etc.
JJKizak wrote on 1/11/2005, 6:05 AM
I once thought I couldn't hear below 40hz, but then after getting the sub woofer I could hear to 20hz. I once thought I could hear 16khz but then it went down to 14 khz then now to 12.5khz on a good day. And thats with plenty of power output. After 12.5 Khz there is nothing. And most acoustic properties of Home Theaters are so bad you have to jerk the hell out of the levels to get it to sound right.

BillyBoy wrote on 1/11/2005, 6:30 AM
For what its worth I didn't invest thousands in speakers. While audiophiles and purists may snicker, I found that the Sony towers models SS-MF750 for front R/L and SS CR550 (center) to be very capable in their price range.

The 750 is a discontinued version, had to hunt for it, shame it has two woofers while the newer SS-MF550 has only one. Gets rave reviews and hearing it myself and far more expensive speakers in a sound room a Fry's I wasn't about to spend hundreds more per speaker just to get snob appel on the label. If you're in the market, check these out, if you wife won't kill you for spoiling her interior decorating scheme, because they are kind of big, standing 41 inches tall, so for sure, floor models, not bookshelf.
Laurence wrote on 1/11/2005, 7:02 AM
Once when I was doing audio for a dinner show, OSHA came in with a state of the art DB meter to measure workplace noise. Since I had a cheap Radio Shack one right next to me, I put it next to the OSHA meter and see how the two of them compared. They gave exactly the same readings. If you are going to get a DB meter, a cheap Radio Shack one is fine.
BillyBoy wrote on 1/11/2005, 1:32 PM
OK.... I picked up a digital sound meter at Radio Shack, only $10 more then the analog model they didn't have. Does it make a difference?


The Denton A/V receiver helps of course because you can input the distance of each speaker in one foot steps which all by itself gets it close, because it will caculate the delay all by itself, then it gives you test tones one speaker at a time to fine tune. Turns out my "ear" was pretty good, only off 1-4 dB depending on channel, so in a couple minutes I had all six channels within one DB of each other.

Creature comfort question:

What overall dB setting do you run your system at? Seems if I set up the main volume so I get between 82-86 dB on the meter its well within my tolerance range and still get good bang in bass and no neighbors banging on the door, not yet anyway. <wink>

riredale wrote on 1/11/2005, 3:08 PM
J Jkizak:

I think once you get down below 40Hz or so you more or less "feel" the energy rather than hear it. In fact, if you can hear a low note it might be because the system is non-linear and you're really hearing the harmonics.

Sidelight: at the CES show last week in Las Vegas, one company was showing a 24" woofer, mounted on a truck bed, being driven at about 5Hz. The cone was moving back-and-forth about 4"! Of course, you couldn't hear anything, but it was cool to see. The speaker frame was hot to the touch.
daryl wrote on 1/12/2005, 6:36 AM
Interesting stuff!

My 2c, if this is your home system, set it up to sound what YOU want it to sound like. Just because the test gear says it is properly configured, if a different setting sounds better to you, DO IT, it's YOURS. Unless you plan to charge admission to crowds of people, don't worry about technical specs, get whay you want. I've played in quite a few bands, and been around a lot of concerts where the sound crews spend hours measuring measuring setting setting measuring until all their test gear is lined up on the "perfect" setting, yet there will be an obvious "harsh" sound of some kind. The better companies ignore the test gear at this point and fix the problem, the lesser xppeirenced ones will think, hmmmm, doesn't sound good, but my meters say it's great.
JJKizak wrote on 1/12/2005, 8:06 AM
24" woofer on a truck. God, I love it. Maybe use them as the basis for theatre seats in your home setup. "Feeling is believing".