Question on surround speakers set up

[pezboy]

Hello,
I finally hooked up the 2 rears speakers in my 5.1 system and am wondering how to set them up. I've never heard any surround, let alone a properly set up surround. My first question is, how loud should they be compared to the fronts? Are movies and music mixed so that all of the speakers output the same volume, or are they supposed to be quieter? Second, my room is 18 feet wide and I had to put one 2 foot farther out on the left than on the right. How many decibles louder should I make this one to compensate for the difference in distance? Thanks for your help.
Dustin

 

[Adam]

Hi. Which receiver are you using? It might be able to set it up for you and/or be able to output test tones to help you set the volume levels correctly.

The audio going to rear speakers is often much quieter than what goes to the front and center speakers, and there isn't always sound coming out of them during a movie. Sometimes it does get loud, but it all depends on the audio track.

 

[DTS]

Here is a link to some good articles-

http://www.audioholics.com/tweaks/speaker-setup-guidelines/

It will help you see how things should be set up. All the speakers should be set to the same "loudness" level. This should be done with a SPL meter to insure accurate levels. You can use a disc that has a THX setup feature to get you started. I think you will see that the 2 "rear speakers" are placed to the side, then for 7.1 2 speakers are added to the back. I'm sure more help is on the way.

 

[pezboy]

Thanks for the replies. I did run an auto calibration on my setup and it set the right rear to +1db and the left rear to +2 db. It's just that it is very hard for me to tel if both rears are the same volume in my seating position. Also, I didn't know if they were supposed to be as loud as the fronts or not. They are quieter, so they are probably set at a good level. Reading over using an SPL meter, I have no idea what the guides are telling you to do. It says to adjust each speaker to +75db. I can only adjust my speakers from -10db to +10 db. Do they mean keep adjusting them until they read 75db on the meter? I think I have a couple of dvds or blu rays with THX and I will try that out after I send this message.

 

[Adam]

The rears should be as loud when you are running test tones - I was trying to say that most movie tracks don't have nearly as much sound being sent to the rears as is sent to the fronts and center. So, while you watch a movie, they won't sound as loud.

Your receiver will let you adjust the speakers levels from -10dB to +10dB to allow you to adjust them (if required) relative to the other speakers. When it talks about 75dB on the SPL meter, that's what the meter will read when you are playing the test tones. I think that most auto set-ups do a good job of setting the speaker levels, so you probably don't have to change anything.

If you want to manually adjust the speaker levels, here's one way to do it. You could start playing the test tones (which probably start with one of the front speakers) and adjust the volume on the receiver until the SPL meter reads 75dB. Then, have the receiver move the test tone to the next speaker, and adjust the speaker level setting on the receiver (somewhere between -10dB to +10dB) until the SPL meter reads 75dB. Progress to the next speaker and do the same. Continue that until you've done all of the speakers.

EDIT: The SPL meter should be put on "C" weighting and the response set to "Slow."

 

[lsiberian]

Thanks for the replies. I did run an auto calibration on my setup and it set the right rear to +1db and the left rear to +2 db. It's just that it is very hard for me to tel if both rears are the same volume in my seating position. Also, I didn't know if they were supposed to be as loud as the fronts or not. They are quieter, so they are probably set at a good level. Reading over using an SPL meter, I have no idea what the guides are telling you to do. It says to adjust each speaker to +75db. I can only adjust my speakers from -10db to +10 db. Do they mean keep adjusting them until they read 75db on the meter? I think I have a couple of dvds or blu rays with THX and I will try that out after I send this message.

Your fine. Time to stop asking questions and start watching movies What you watching?

 

[mtrycrafts]

...It's just that it is very hard for me to tel if both rears are the same volume in my seating position.

Is that because the volume is so close that you cannot be sure if they are the same level or not?
If so, then that is what you want, you are set. The auto calibrator sends out a signal to all speakers at the same signal level, so the speaker output needs to be the same. This would also happen with a manual setup.
Your receiver would send the same signal to all the speakers and you should get the same SPL on the meter. But, some receiver's master volume control needs to be turned to the appropriate level to achieve this; can be a bit more complicated.

 

[pezboy]

The sound output during the tests really doesn't help me when determining if they are the right volume compared to my fronts and center because it does one right after the other and doesn't let me switch back and forth. When watching a movie or music, one side seems louder than the other at times and then they both sound the same at times. I don't know if this is because of the audio mix, or if one of the speakers is quieter than the other. I am the kind of person that can't leave well enough alone, so I will probably get an SPL meter and manually check it. I'll ask one question now before I buy the meter though. It says to do the check at 75db, what volume level does that correspond to on my receiver? -15db? Thanks.
Dustin

 

[lsiberian]

The sound output during the tests really doesn't help me when determining if they are the right volume compared to my fronts and center because it does one right after the other and doesn't let me switch back and forth. When watching a movie or music, one side seems louder than the other at times and then they both sound the same at times. I don't know if this is because of the audio mix, or if one of the speakers is quieter than the other. I am the kind of person that can't leave well enough alone, so I will probably get an SPL meter and manually check it. I'll ask one question now before I buy the meter though. It says to do the check at 75db, what volume level does that correspond to on my receiver? -15db? Thanks.
Dustin

That sounds like a balance issue. Adjust your L-R balance one tick to the side that seems quieter. That should help.

You may have some hearing loss in one ear or something may have messed up the eq on the L-R balance. But you can tweak it till it sounds right to you. Your ears are the ultimate test.

 

[just-some-guy]

i like my surrounds about 4db higher. the way i judge this = while watching a movie, a scene comes up that has "engulfing" backround noise = like being in the middle of a large/loud crowd. i adjust so the sound is coming even from all around. as it would be if i were standing in the middle of that crowd.