Calibration makes a difference

[SMiLEY]

I calibrated my system with the ol' radio shack SPL meter this weekend, and man it really does make a difference.

Following some advice I've found I set all the speakers to 75 dB and the subwoofer to about 79 dB. The bass I'm getting out of movies now is kinda frightening. But it's so much fun I hardly notice the rattling windows.

Oh, and I just got reamed on an eBay auction for a demodulator. I won't say how much, because it's kinda embarrassing, but at least I'll have Star Wars in Dolby Digital, right?

[Andrew Pratt]

I agree getting your sound system in check is a very big and rather cheap tweak that most people either don't bother doing or try to do it by ear.

[John Holmes]

Using the meter makes a big difference. I don't know how anyone can do it by ear. Everytime I tried by ear and then checked with the meter, I was never close to the right settings.

Congrats on scoring a demod. Soon you'll enjoy DD so much that the cost, will be just a faded memory




"I came here, to chew bubble gum and kickass. And I'm all out of bubble gum!!!" My DVD's

[Lexman]

Way to go Smiley. We all should take the time to do this now and again. Um, namely me. I bet my battery is gone in my meter. lol.

Lex

[KennyG]

I am planning to buy Radio Shack's digital unit very soon. It's fairly easy to get the front sound stage very close, but trying to match that to the rears is alot tuffer. I don't use a sub, so that's of no concern to me.
Kenny

[Kerry Hackney]

I have a question about calibration. If you set up the db meter on a camera tripod facing the front of the room at your listenting position is the microphone on the meter facing directly between the mains? Or do you aim it at each speaker as you balance? I am most curious about the rear surrounds. Do you aim the meter at them?

[Andrew Pratt]

Kerry I always just leave it pointing at the TV when calibrating but you raise a good question re the rears.

[Markj]

I read the instructions for the SPL meter and you should aim the mic at the ceiling. That is what I did and also I stood out of the way of the speaker I was calibrating.

[SMiLEY]

When I was trying to find out exactly how to do this, I found several opinions. It made the most sense to me to have the meter pointing straight up, but my tripod wouldn't really allow that so I was pointing it towards the ceiling at an almost 45* angle (towards the TV), another method employed by many people. It was pretty successful for me.

[Andrew Pratt]

the next time I've got some free time I wonder just how much difference it really makes? I wonder what the differences would be if I playing a test tone and measureing it pointed towareds the speaker, away from the speaker and up at the ceiling...

[P-Dub]

I'd be interested in hearing some of the steps taken during calibration. I've recently purchased the RS SPL meter so I finally tried to calibrate my system. The only calibration disc that I had at my disposal was DVD Spectacular. This dvd includes pink noise and frequency sweeps.

I started the pink noise test, and that just rotates pink noise to all five channels.
I setup the meter to C and Slow and set it to measure at 70.

As I'm going through the tones, I've gone through and tried to balance the speaker levels such that my meter is reading 75db across all speakers. This means I've changed my left/right balance, and reduced my centre to -3db and kept my rears at 0db. This is about as close to an even 75 as I'm going to get. I did not use a tripod, so this was all done with me scrunching down a bit and pointing my meter towards the ceiling at about ear level.

A few thing about playing the test tones and getting a 75db reading. This is freaking loud! I had to put in some earplugs cause I couldn't stand the constant noise at that level. My volume setting was resting at about the 11 o'clock position. I don't think I've ever had it that high.

Now the scary part. I then tried to set my LFE/Sub level. I didn't change the volume settings, nor the sub level settings, and let an LFE sweep rip. Rip is right, I damn near destroyed my sub! :E Things were windows rattling, shades a shaking and I generally feared for my life. Well I feared more for my equipment than my life. My sub is located in a corner and is connected from the LFE out directly to the Sub, bypassing the level adjustment. I've set my receiver to all speakers small, and bass to SW. The LFE is set to 0db and the SW level is set to -3db. I came to that setting before calibration on a trial and error, and basically what I thought sounded good.

So I figure I must have done something wrong. I reduced the main volume and then reduced all the sub levels down to -20db or Min. I recalibrated my speakers to about 65db as that is about as loud as I can realistically listen. Then I went back to to some LFE sweeps and to figure out my levels.

In the end, I ended up with pretty much the same levels. LFE 0db and SW at -3db. I was measuring the LFE sweeps to 70db, which is about 5db over my speakers.

So did I do this right? I know my speakers sound much better on front pans, I tested with Super Speedway and it did sound much better.

For my sub, could I have damaged the driver with the obscene volume level? I mean it really sounded bad, not really wanting to reproduce that again. On some subsequent demo's, it sounded normal.

My equip is listed in my profile.




Paul

There are three kinds of people in this world; those that can count, and those that can't.

[John Holmes]

Paul,

I am glad nothing was blown. I think you are pretty much there. One thing about the 75db standard. It is what you should calibrate to, not a must. It also does not mean that you have to listen to playback at that level. Once you calibrate at 75db, you can still adjust your volume knob to your desired listening pleasure! However, calibrating to 75db will give you certain debating rights when discussing gear for, everyone will/should be cal to the same levels.

Also, just having all the speakers cal to 65, 85, 71 etc. will yield the most important part. That is all speakers are the same level! Which is much more important than being at 75db.

I have Avia and found that when I cal to 85db (Avia's standard) my receiver's test tone gave me the exact same readings only at 75db. Now I just use my reciever's tones and only use Avia for video.




"I came here, to chew bubble gum and kickass. And I'm all out of bubble gum!!!" My DVD's

[George Bellefontaine]

I did the same as Markj and calibrated to 75db.




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[Bob Santos]

Smiley,, Yes it's increadable how much better a system sounds after it has been properly calibrated.
I was amazed at how off my ears were when I first set mine up with the SPL. A definate must have for a HT enthusiast.

Now about the direction to point the SPL.
Thats a interesting question. I allways mount mine on the tripod pointing toward the TV. I have a replacement Reference 30 coming tomorrow, so I will be setting it up. I will try pointing it up, and see if there is a difference.
I'll report back tomorrow night.

[Lex]

Good info and discussion here guys. Kenny, don't waist your money on the digital unit. Actually, the digital only measures in whole dbs, and the analog measures in half dbs. everyone in audio circles says don't get the digital unit.

Bob, hope the new ref 30 calibrated nicely

Lex