Matching 5.1 component sensitivity

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newguy
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Matching 5.1 component sensitivity

Postby newguy » Wed Jul 12, 2006 5:16 pm

I'm running a pair of JBL N24 rear surrounds (4" ported), a NR JBL center and some AR 318ps (3 way ported 8") towers for the mains...

Problem? is that the mains seem to really overpower the rears by a fair margin...My old Technics SA-DX930 has 10db cut/boost for the center/sub and rears but not for the mains.

Even w/the rears boosted to 10db (max), they are barely adequate for the rear fill....Did some research and the AR mains are rated at 90db and the rear JBLs are 86db...obviously a decent mismatch.

What would you do?

Find a receiver that lets me dial down the mains as well as the center/rears?
Replace mains?
Replace rears?

Thing is, I got the fronts and rears for great deals so I don't want to invest too much but I do want to hear more from the rears...I've considered some matching/similar fronts but the towers are great for music....

Just thought I'd pick some brains....
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jmaxima
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Postby jmaxima » Wed Jul 12, 2006 9:20 pm

Cheapest method, and perfectly acceptable would be to use a passive method. L-pads for the mains.
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Robert_J
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Postby Robert_J » Thu Jul 13, 2006 4:16 pm

How are you determining that the surrounds aren't loud enough? Normal listening? Receiver generated test tones? SPL meter?

Proper calibration requires a test disc like Avia or Video Essentials and the Radio Shack SPL meter (cheapest decent meter on the market). It's about a $40-$50 investment but it will guarantee the proper speaker levels.

-Robert
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newguy
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Postby newguy » Thu Jul 13, 2006 8:01 pm

Primarily by ear and in comparison w/a friend's setup. Now before anyone yells, I've used the same DVD in both setups and the friend's Sony rear surrounds are much louder. With mine, the ambient sounds are much less audible....

Where should I pick up one of these test discs?

And considering the large difference in sensitivity, the L pad may be the way to go...it wouldn't be so bad if the surrounds had the higher sensitivity level because I could lower the output level but the mains are just overpowering the rears too much...


Jeremy
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Robert_J
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Postby Robert_J » Fri Jul 14, 2006 7:29 am

Avia - http://www.ovationmultimedia.com/avia.html
Video Essentials - http://www.amazon.com/gp/product/B00005PJ70/ref=pd_lpo_k2_dp_k2a_3_txt/104-3550584-0740747?%5Fencoding=UTF8&v=glance&n=130
Sound & Vision Home Theater Tune Up - http://www.amazon.com/gp/product/B00005TRZA/qid=1152880008/sr=1-1/ref=sr_1_1/104-3550584-0740747?s=dvd&v=glance&n=130
SPL meter - http://www.radioshack.com/product/index.jsp?productId=2103668

Any of the DVD's above along withe the SPL meter will work great. I use Video Essentials. It has detailed step by step instructions on the DVD how to properly set up both your audio and video along with the appropriate test tones and test images.

-Robert
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Mlstrass
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Postby Mlstrass » Fri Jul 14, 2006 10:27 am

I have matching Klipsch Legends all around and they've been calibrated. When watching movies the rears do NOT put out as much sound as the mains. Just how the majority of movies are mixed.

I run my center and rears hot, +4, and I'm guessing your buddy may be doing the same. Another possibility is that your "old" receiver puts out less power to the rears. I had an old Pioneer that did that, only 25wpc to the rears, but 100wpc to the mains. I vote for updgrading your receiver.

I say this because it seems that bringing the mains "down" to the level of the rears could leave you less than thrilled with your set up.
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Robert_J
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Postby Robert_J » Fri Jul 14, 2006 11:09 am

Mlstrass wrote:I say this because it seems that bringing the mains "down" to the level of the rears could leave you less than thrilled with your set up.
Thta shouldn't be a problem either. Just turn the volume knob up a notch or two to compensate for lowering the fronts and it will sound EXACTLY the same.

My receiver doesn't have a balance control but I can adjust each of the 7 speakers and LFE +- 10db. My left speaker is about 2db louder due to it's position near an uncovered wall. The right speaker is next to a curtain that absorbs some of the reflected sound. During the auto-calibration, the left is set a little lower and no EQ is added while the right is set at "zero" on the ajustment and 3db is added to the treble.

-Robert
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newguy
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Postby newguy » Fri Jul 14, 2006 4:43 pm

Well, all he owns is a HTIB setup and has done nothing to it, though the factory system may be setup in such a way as you describe...

I'll have to go back and see what my receiver puts out to the rears....all I know at the moment is that it does 100 or 110x5 (DD/DTS,etc)....another issue that I've found others have encountered is that it doesn't like to play in DTS mode though it's built to....
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Postby jlaine » Sun Jul 16, 2006 11:06 am

I would just get a new 5.1 receiver... That's your main problem right there anyway - and snag the radio shack SPL meter as it is a handy tool to have around.

I thought to get the DD logo they all had to have built in noise generators and have adjustable volume levels for the channels... Wonder if that was THX certification... So many damn rules I forget all of them now. <blah>
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Postby --m-- » Sun Jul 16, 2006 11:45 am

I think your trying to run your rears on the hot side. The rears aren't there to add volume but to add ambience/depth. When set up properly you will rarely hear them unless you have something specif fly to the back of the soundstage. At firt it sounds wrong with not always hearing them...but once you get used to it you'll start picking out the little nuances in the soundtrack.
Once you've hit rock bottom there's only one way to go....sideways

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