Axiom Home Page Forums General Discussion Technical Questions SPL Meter

I've dealt with attorneys way too often and JohnK is very emblematic of the profession . A kindhearted attorney with truculence to boot . Wait, did I just say that all attorneys are kindhearted??

PS. John, I hope you don't take that the wrong way.

Well I better brush up on my Japanese then

I see. An everythingbot. Very rare, those.

PeterChenoweth, thank you for the detailed explanation.

So I need to run a test tone and raise the main volume of my receiver until I hit 75 db using the spl. The run the test tones for each speaker making sure they are all 75db.

I think I would have to have each speaker slightly different to each other as I am not in the center, Maybe I would have a difference of -2db for the speakers closest to me?

You adjust each speaker's level according to the reading on the meter, so yes, the nearest speakers to you will have lower settings than those farther away.

Yes. The level that you choose as your baseline isn't that important. The goal is that you equalize all of the speakers to that baseline. I think that most of use use 70, 75, or 80 db. Depends on what you're comfortable with.

Whatever tool you use, whether it's a test DVD or tone generation as a setup function of your receiver, the point is the same. You'll play a test tone through one speaker, perhaps the left front. Then you'll adjust the main volume control to hit a specific db*. Say 75db. Now you'll either go to the next test (on a DVD) or change the tone to the next speaker. Perhaps the center. Now you will NOT use volume knob, but you'll use whatever calibration function that your receiver has to adjust that specific channel level up or down. If it's reading 73db, add 2db of trim. 79db, subtract 4db. You get the idea. And you just do that for every channel in your system.

A sub (including the EP500) really isn't that much different. Your receiver should have a trim level for the sub as well. However, the sub is unique because it will have it's own level control because the sub has its own amp. Usually a knob on the back. There should be recommendations on where to start with the EP500's gain level in the EP500 manual. It's a bit of a balance between how much gain you want to add or subtract from the receiver's trim vs what the EP500's gain will be set to.

For example, if you set the receiver's sub trim level too low, you may send the EP500 too little of a signal to trigger its remote turn on.

*Some receivers, like my Pioneer Elite, automatically set the volume control to a specific point when I tell it I'm calibrating the speakers. In this case, I don't have a choice in what the baseline db reading is. I just match all of my speakers to whatever db is produced by the left-front speaker.

Graeme - just to reiterate, in theory, you want to calibrate the sound level from each speaker so that the SPL meter indicates the same volume for each speaker.

In actual practice, however, many listeners calibrate their center speaker 2-4 dB higher than the rest (i.e. turn it up until the SPL measures 77-79 dB if the rest of the speakers are at 75). This is done because it helps to more easily hear movie soundtrack dialogue. Additionally, as others have noted, some of us like to run our subs a bit louder than the rest as well (myself included). I calibrate my subs to +3 dB than the rest of the system (again, around 78 dB).

Experiment to see what you like. These are just guidelines, but they should get you close.

Jason

You know, considering that many of us run the center a few dBs hot, the sub a few dBs hot, and the surrounds a few dBs hot.... When I calibrate tomorrow, I think I'll just run the Mains a few dBs cool....

Thanks to all for the input, I plan on trying to set it up properly tomorrow when the wife is at work.

The thing that I will have trouble with is the EP500, I have set it up according to the manual that came with it but it does not blow me away. I am a little disappointed actually. But I will have to try and find the best place for it and then try tweaking it.

Graeme, are you familiar with the idea of a "sub crawl" ?

If not, it's an easy way to find a good location for your sub. Rather than moving it from place to place then running back to your seat to see how it sounds, you reverse the process - put the sub in your listening position, play a DVD or CD with a decently broad range of bass, then walk around the room until you find where the bass sounds best. Put the sub there.

Bonus points for crawling, since the sub will be on the ground. If your friends laugh at you, sit in your listening position and make THEM drag the subwoofer around the room.