finally got an spl meter, now what?

[bismarck]

I finally went down to the rat shack and bought their analog sound level meter. Now i am just not sure what to do with it. I know to play my test tones on my reciever and make them all the same level, right? or is ther more i can do with it? Anyway, i am just wondering how many dbs i want the test tones to be and what the heck is A and C weighing. I sure hope this makes a difference because I hate spending money, it runs in the bllod, German.

[Arky]

Can't sleep tonight so i'll give you my limited knowledge.

The C measurement holds the needle steadier than A while testing. It's slower so easier to read. The majority of posts I read say to use Avia or Digital Video Essentials setup discs & yes set the levels the same. You want the meter pointed up, steady & ear level at listening position. Some will say use 75 as reference others 85. Then the debate starts about what "is" reference, THX etc.

It becomes interesting reading. I used 75.

Personally I would like to know how to set sub phase correctly in conjunction with the spl level.

JT

[BobbyT]

The Sound&Vision disc is good for beginners. It has tutorials on what each calibration does.

You'll need to set the volume on your receiver to 00. The 75db or 85db will depend on which disc you use to calibrate with. With the spl meter set to say 85 then when the needle is on 0 it's 85db. as said above set it to C weighting. And set it to slow response.

[travisc]

Personally I would like to know how to set sub phase correctly in conjunction with the spl level.

JT

Avia tells you to sit a the listening position, play some bass heavy track and have someone else toggle the switch. the one that sounds the loudest is the one you want. I have noticed that the spl meter doesnt pick up phase cancelation very well.

[Arky]

Thanks Travisc

I missed that on Avia. I'll give it a go.

JT

[tkot]

most of the advice above is correct

the one thing i question is the 00 referance for your master volume.why cut yourself short(due to my room and stuff my levels are set l+1/c+2/r+2/rl+2/rr+2/rsl+3/rsr+3/sub1+3/sub2+4) and i have never come close to 00 on the master volume when watching movies i think the loudest ive had a movie is-35.

i would suggest that you start with one of the main channels and set the channel level to +1 then adjust the main volume to get the 75/85 db.

then move on to the rest of the channels

the center and rears will most likely come in a few db higher on thier individual channel set ups(smaller speakers distance ect)

this will make the most of youe available power and leave more headroom in your system

then set the sub from 3 to 5 db higher than the mains

and you will be closer to what things should sound like.

and remember that dd and dts sound different and may require different set ups

good luck!

let the fun begin!

jay

[ygmn]

....i would suggest that you start with one of the main channels and set the channel level to +1 then adjust the main volume to get the 75/85 db. ....

why set the main to +1?

Set the main volume such that the L or R speaker is at 85db c weight slow response

(75db if 85db hurts your ears) then leave it alone...do not touch it again....

then balance each speaker such that they play the same level you set the L or R speaker to....85dB (75dB). adjust level for that speaker using receiver setting menu option thingy

SPL meter to be in main listening position and pointing straight up.

now when ya watch movies...set the master volume knob to this position that you had it set in the first step....this will ensure all movies are played at reference levels

Good luck

[BobbyT]

most of the advice above is correct

the one thing i question is the 00 referance for your master volume.why cut yourself short(due to my room and stuff my levels are set l+1/c+2/r+2/rl+2/rr+2/rsl+3/rsr+3/sub1+3/sub2+4) and i have never come close to 00 on the master volume when watching movies i think the loudest ive had a movie is-35.

i would suggest that you start with one of the main channels and set the channel level to +1 then adjust the main volume to get the 75/85 db.

then move on to the rest of the channels

the center and rears will most likely come in a few db higher on thier individual channel set ups(smaller speakers distance ect)

this will make the most of youe available power and leave more headroom in your system

then set the sub from 3 to 5 db higher than the mains

and you will be closer to what things should sound like.

and remember that dd and dts sound different and may require different set ups

good luck!

let the fun begin!

jay

Most receivers reference level volume is at 00. At least on Yamaha, Denon, and Pioneer. Before running the test tones the volume should be set at reference level, then balence all of the speaker levels. This has nothing to do with the volume number at which you watch movies. If you balence all of your speaker levels to 85db with the volume at -35 then when you push the volume to 00 or higher you will risk distortion, clipping, and speaker damage.

He can't set up his system by your numbers because he has different equipment in a different room.

Running the sub hot is a personal preference. Some people leave everything equally balanced and others prefer to run it hot. That too will depend on room and equipment.

[travisc]

Ya I like the sub around 5dB hot as well. Like a little oomph if ya know what I mean

[BobbyT]

I run mine a little hot, about 2-3db high. I think most people run the sub a little over. Although I do know a couple of people that want everything perfectly equually balanced. It's all personal preference on sub levels.

[bismarck]

I personnaly like my subwoofer to blend in with the rest of the system. I have the sub-12 at 1/4 gain and bass at -2db. I think I will set my reciever to 00 at then set all the speakers to 85db. I use the testones to do this right? I also point the spl meter stright up at the ceiling, where is would be sitting at ear lever?

I am also wondering about these cds i have heard so much about, like avia, how basiclally everyone has one kind or another and uses it for just about every kind of tweak. Where can i get one, and what do they really do? Is it just a cd with some sound fx and whatnot,or am I missing the idea completely?

[travisc]

disk is a little over rated, thx optimizer does just as imo

[colterphoto1]

Put the meter on a stand, so handling noise doens't translate, try to stand away from it so your body doesn't interfere with the readings. I think the Radio Shack manual says to measure with the meter pointed AT RIGHT ANGLES to the source noise.

[Mike Lindsey]

I was told how to calibrate by a gentleman named Vince Maskeeper out on http://www.hometheaterforum.com]www.hometheaterforum.com . The thread in question is no longer but here is what he had to say:

He explained that reference level is considered to be setting your speakers so that the LOUDEST possible sound coming out of any one measures 105db in Sound Pressure at the listening position in your room.

Now, how do you do that?

Well, someone could record a disc with a tone on it for you that is encoded as loud as possible -- you could play that tone in your room and measure it with a meter and set your receiver so that your speaker plays at 105db.

You COULD do that, but it would probably be a very, very unpleasant experience. No one wants to be blasted with full volume just to set his or her speakers.

So, the guys making the test tone discs said "Hey, why don't we just make the tone so it is a specific amount lower than maximum, and the guy using it at his house can just calibrate to the lower level!"

And thus they did. Video Essentials (VE) created a tone that is exactly 30 steps below maximum. Since we said maximum was supposed to be heard as 105db in your room, 30 steps below 105 is 75. So since you know the tone on VE is 30 steps below full level, you can measure that to be 75db in your room and achieve the same result! Now you would have it set so that the loudest sound would be 105db.

From what I understand, Ref level is 00db on the receiver volume??? 00db is loud in my small apt (normally listen to -20 to -30 with each channel level set to 0db and mains and center set to small).

Okay, here is where it gets a little tricky. Two points to remember:

1) Ref level just means calibrated so that the maximum level is 105db peak in volume in the room at the listening position. The position of the volume knob really means nothing.

Think about it this way - if you moved your current receiver and speakers into your favorite concert hall, and set it up on the stage and sat in the back row, the volume knob would have to be much HIGHER to get the same sound level to you WAAAAY back in the back row. More so, imagine taking the speaker system you see traveling with an arena rock band like Aerosmith. If you set that up in your living room - it would probably not take much to get your room really loud!

The point is - the key to ref level is OUTPUT. It is a measured output. If your volume knob ends up at 00 for ref level then great. If not, it could be at -04 or +03, or whatever.

My Denon allows me to adjust every channel, including the front L/R speakers, in the speaker setup menu. So I have set my volume knob to -10 and then adjusted all the speakers so that they measure correctly. I did this just for ease of use on my part (-10 is easy to remember) -- I could have easily set the knob to 00 and adjusted the speakers to that point (but the tones were just too damn loud).

Some receivers don't let you adjust the R/L speaker - just center and surrounds. In that case, you simply adjust the volume knob so the L/R speakers measure correct and adjust center and surrounds around that. Again, in either case - where the volume knob ends up is correct - no matter what it reads. Just take a note of it.

2) The second point you need to keep in mind is this: Ref level is not necessary. Most, if not all, HTF members listen most of the time below ref level...Ref level is pretty loud.

Note by me: That's because they're not using Klipsch speakers.

The real key to calibration is to match all the speaker levels in SPL - making them even. It's good to also know where the REF LEVEL position on the volume knob is - but I usually find myself hovering somewhere between -05 and -10 of ref.

Again, the big key is to calibrate to match speaker output levels -- beyond that is YOUR HOME THEATER, adjust the volume knob to where you are comfortable listening. That's why the volume knob is there!

What I would do is this:

1) Set the volume knob to 00

2) Adjust the levels using test tones and the SPL meter. If using VE, all tones should measure 75db. If using Avia, they will measure 85db.

3) You now have a system calibrated so that 00 is dolby ref level. Adjusting the volume knob will adjust all the speakers evenly - so you can now adjust the volume to the -10 or -20 position you normally listen at.

You don't need to specifically calibrate for where you plan to listen. In fact, if you tried to set the volume to -20 and adjust the channels to 75db, you probably couldn't get them to go high enough (again, he wasn't thinking of Klipsch when he said this). And even if you could, your -20 position would now be set so that it was ref and you'd probably want to turn down to -40 when you want to listen to it.

Keep in mind REF LEVEL will measure output. Just set it up so that 00 is correct and then adjust the volume to where you are comfortable listening...

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Mike

[bismarck]

Thanks for the info mike. If my speakers,

b-3, c-2, s-2, sub-12 can't go to 105db, then what. Do i just set the volume to 00 then run the test tones and adjust everything to xxdb?

I am slo wondering how much past the db's a speaker can handle you can go before damaging the speakers.

[Mike Lindsey]

Thanks for the info mike. If my speakers, b-3, c-2, s-2, sub-12 can't go to 105db, then what. Do i just set the volume to 00 then run the test tones and adjust everything to xxdb? I am slo wondering how much past the db's a speaker can handle you can go before damaging the speakers.

That would be correct. On my Denon the volume goes to +10. I used the VE disk and set my reference at -10. I have never had my volume turned louder than -10 while watching a movie, concert or DVD-A.

As for how loud can they go check the specs. I believe my La Scala's can go at least 115db. I know people who have pushed them louder than that.

Mike

[tkot]

sorrry this reply is late

first, i like to start off a little hot

(thats why i suggested to use +1 on the initial set up)

second, if you use a pre/pro, as i do and you have bigger amps than you need(as i do, over 10k watts peak)

then the 00 reference means nothing!

at 00 on my master volume my system is at 140 db+

(so why would i take all that headroom out of my system,by useing 00,at 85db, as the reference volume?)

that said, how can you say that the manufacture uses 00 as the reference volume?

if you have a 50 wattx 5/6/7 channels how can you compare it to a 100 wattx5/6/7 amp or 8 bridged amps at 1000+ watts

00 voume as a reference could be meant to be read as the max clean volume of a particular set up/ amp ect

but to say that 00 is THE REFERENCE is silly!

jay

[DrWho]

Can't sleep tonight so i'll give you my limited knowledge.

The

C measurement holds the needle steadier than A while testing. It's

slower so easier to read. The majority of posts I read say to use Avia

or Digital Video Essentials setup discs & yes set the levels the

same. You want the meter pointed up, steady & ear level

at listening position. Some will say use 75 as reference others 85.

Then the debate starts about what "is" reference, THX etc.

It becomes interesting reading. I used 75.

Personally I would like to know how to set sub phase correctly in conjunction with the spl level.

JT

Just a little correction....though you percieve C as being quicker,

that is not the difference between the A and C weighting. The A

weighting takes the input from the mic and runs it through a filter to

simulate the frequency response of our ears so that the SPL

measurements correspond to what we percieve as changes in loudness. I

forget the actual numbers, but I'm pretty sure frequencies below 100Hz

and above 10kHz are removed. The C weighting however is a perfectly

flat response - I think from 20Hz to 20kHz is the goal. The easiest way

to demonstrate the differences between the weightings is to listen to

some music with a muddy bass solo...you will measure huge differences

between A and C weighting simply because of the frequencies being

measured (C will seem louder than A). And just to complete the

thought...the ratshack meter doesn't have a flat frequency response, so

its not exactly very accurate across the frequency ranges, but at least

it gives you a good idea.

There is another switch on the ratshack meter "fast or slow" - this

will change how quickly the needle responds to the sound source. For

system calibration you always want to be C weighted with the slow

response - and ideally you would put the meter on a stand or in some

place free of vibration.

As far as "reference" levels go...I wouldn't get too caught up with it

all. Just leave your LR balance at 0 (so as to bypass the circuitry on

the important channels) and then adjust the center and surrounds so

that everything balances out. The meter works very well for setting the

relative volumes of all the speakers but the subwoofer - where there

are other issues coming into play that make it much better to tune by

ear (though you can start off matching the volume with the meter and

then going from there).

Btw, you will find many of these answers in the manual that came with

your meter...I would highly recommend reading it as they have spent way

more time making sure they worded everything correctly.

[bismarck]

Well, i calibrated everything. i believe i ahve my surround at -3db, my center at -4, and my mains at 0. Thanks agian for all the info, coming in and reading to all the audio advice reminds me what it sounds like being on the recieving end of information, as I sell computers, printers etc.. and usually am telling the info. I bought "Tears of the sun" tongiht so I am exited to see that. Maybe I am the only one, but i hate buying movies i have already watched, I also hate spending more than 10 bucks on a movie. It's being German, we are all really tight with our money, buying these speakers killed me and I wouldn't have w/o getting a good deal.