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2 Center Speakers


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15 replies to this topic

#1 of 16 OFFLINE   drobbins

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Posted January 25 2005 - 05:43 AM

I would like to hook up 2 center speakers. One above and one below the screen to help center the voices with the picture. I have JBL 8 ohm speakers. How can this be done? In series or in parallel? My receiver will handle 6 ohm speakers, but not 4. Will it effect the volume for the center channel? Is there something I am missing?
Dave

#2 of 16 OFFLINE   John S

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Posted January 25 2005 - 06:16 AM

I'd do parallel, at 4 ohms.. Most AVR's easily handle this on one channel. Another story if every speaker attached is 4 ohm for sure. The additional power on the dialog is an advantage in my experiences with it. I run two just this way on my Denon 4802 for a long time now.

#3 of 16 OFFLINE   JimHaskell

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Posted January 25 2005 - 06:30 AM

Running parallel will increase the sound output by 3 dB, so you may have to turn down the center channel. This is good, because you will be using less power on that channel, so the amp won't feel as much strain under the 4 ohm load.

#4 of 16 OFFLINE   JohnSmith

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Posted January 25 2005 - 08:33 AM

You might have combing problems, so I would be careful about positioning or even using two centres in the first place.

#5 of 16 OFFLINE   drobbins

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Posted January 25 2005 - 02:01 PM

My main concern is, if I will damage my receiver or not. I am not much on electrical stuff. Would adding a 4 ohm resister do anything to bring it back to 8 ohm?
The other reason I want to try the 2 speakers is that I am having some troubles with the some midrange frequencies. Sometimes it is hard to hear the dialog and then the action scenes are too loud. I have balanced the system with a SPL meter and replaced the center speaker with a larger one. That is why I have the second speaker. During the "sweep" test it drops out around 80 - 100. I think the only way to see if there is a combing problem is to try it. How would I recognize it?

#6 of 16 OFFLINE   Phil_O

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Posted January 25 2005 - 08:20 PM

Adding a 4 ohm resistor to the output path of the receiver? That's the same as adding a second 4 ohm speaker in parallel at the center channel output, as speakers are just that -- resistors. Two 8 ohm speakers in parallel would equal 4 ohms, which should not be too much of a problem for a robust receiver at moderate volume. If your receiver has an equalizer adjustment you can boost the dB output of the 80-100 Hz frequencies and that would help. Or try repositioning your center. I don't know if putting another one in a separate spot near the first one would help.
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#7 of 16 OFFLINE   JohnSmith

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Posted January 25 2005 - 09:02 PM

Sounds like you should calibrated your system, adjust the dynamic range compression setting, or buy a better speaker (with the last definite improvement over budget centres, centre mix is more intelligible)

#8 of 16 OFFLINE   darrylCHER

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Posted January 26 2005 - 11:12 AM

I would find and buy a better center speaker 10 times before I would use 2 "center channel" speakers.

Also it could be your receiver is not up to the task of clear dialog.

I use mid level gear: (Yamaha 5760, (3)Athena AS-C1's for my LCR, (2)AS-B1's for my surrounds, and (1) Athena AS-P400 sub.

My system is calibrated by the Yamaha YPAO, and double checked/fine tuned with a sound meter.

The dialog on my system sounds like the actor is in my room. Always clear and easily heard no matter how dynamic the sound track is.



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#9 of 16 OFFLINE   Phil_DC

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Posted January 26 2005 - 11:36 AM

Quote:
I would find and buy a better center speaker 10 times before I would use 2 "center channel" speakers.


I would have to agree,

I have heard dual centers , in both side by side configuration and with one above screen and one directly below screen. Neither setup sounded right particulary if you are going to use your HT for high res surround sound music playback.

Even the few people I have heard claim to be running dual 7.1 surround systems I believe only use one center speaker.

#10 of 16 OFFLINE   drobbins

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Posted January 26 2005 - 11:07 PM

I am using a Yamaha 5740 receiver. I have run the Avia calibration DVD. I started out with a JBL speaker that only had 3 1/2 in speakers in it. During the frequency sweep, the volume would drop out starting around 140 and be gone at 90. At 80 the sub would take over. I upgraded the center speaker to a much larger JBL With 5" speakers. (EC25) I have adjusted the built in equalizer for the center speaker, but It's frequency range is limited. It only has one band in the problem range - 100Hz. I also changed the crossover for the sub to 90 Hz. All this helped greatly, but I am still having some drop out and now with the larger center all the dialog "looks" like it comes from speaker, not the actor on the screen. Didn't do this with the smaller speaker. My room is relatively small. I sit back about 13' from a 91" screen with the center mounted directly below it. I was hoping adding another above it would help both with the frequency problem as well as the perception of where the sound originates.
I tried hooking it up last night and recalibrate everything. It did help with perception issue, didn't do much during the frequency sweep, it was much easier to hear the dialog though, and I couldn't quite put my finger on it, but the sound didn't come across as clear as I remembered.
I appreciate all your the input, any more ideas?
Thanks,
Dave

#11 of 16 OFFLINE   darrylCHER

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Posted January 27 2005 - 03:13 AM

Dave, it sounds like you're doing everything you can. Maybe turn the center up 2db or so will help.

I have my center up 1db and my surrounds down 1db from what my YPAO/meter says is calibrated. Thats what I meant about "fine tuning" my system to my liking.

I have only heard 1 double center system, and it sounded really bad. Almost like he was using a bi/di pole speaker for the center. Dialog came from nowhere/everywhere. It was awful.

Just keep messing with your settings, heck try the center in "large" mode. Don't be afraid to try settings that some might think were "incorrect".

Get your system to sound the best for your tastes, no matter what the final settings are!

Test sweeps are great, but I think actual movie scenes are the best test for dialog, bass, sound pans, surround envelopment ect....


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#12 of 16 OFFLINE   John S

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Posted January 27 2005 - 03:23 AM

I guess I am not a purist. I adjust my center, dialog channel per program / content. I always have even when I only had one speaker and over many years of having many different models of single center channel speakers.

I actually adjust my sub (Way Hot), and my center this way. Oh well, it does seem to be working well for me, I will admit usually there are no adjustments needed, but I still adjust them rather freely.

#13 of 16 OFFLINE   darrylCHER

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Posted January 27 2005 - 04:44 AM

Dave, I forgot to ask, is the center speaker aimed up right at your listening position??

If not, find some little "rubber feet" from Home Depot or the like, and tilt the center up so it's delivering its sound straight at you.

This little adjustment makes a huge difference. Mine is the opposite as my center sits on top of my tv.


Darryl

#14 of 16 OFFLINE   Phil_DC

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Posted January 27 2005 - 05:19 AM

If it is on the floor you might be better off with an ajustable center speaker stand like the
SDACC CENTER CHANNEL STAND so you have more control over its positioning.

If it is on a TV then you might want to get some MoPads check out this thread for a link to them:

http://www.hometheat....hreadid=224027

#15 of 16 OFFLINE   drobbins

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Posted January 27 2005 - 05:36 AM

I have my center mounted on 2 shelf brackets below my wall mounted screen. It may be a little lower that my listening position, but not much. I am going to play with it a little more tonight. I am going to try adjusting the EQ more but I will probably do away with the second speaker. It sounded better with out it.
The other factor in this is my ears. My wife always tells me that I don't hear her eitherPosted Image

#16 of 16 OFFLINE   drobbins

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Posted January 29 2005 - 08:08 AM

I ended up tilting the top speaker up some to aim at the seating better and adjusting the tone of the centers to the right & left speakers. This seems to have done the trick. I have crisp clean sound that comes from the screen, not below it.
Thanks for all the input.