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#288156 - 01/22/10 12:36 PM Two Center Channels
Sloped Offline
veteran

Registered: 12/17/08
Posts: 110
Loc: Fonthill
A friend of mine is going to bring over his VP150 so we can see the effects of two center channels on a 7.1 setup. I've notice some of you in the forum here are running configuration like that as well, but usually with a VP100 and VP150.

My question is, do you have these connected in series, parallel or split the preout's to separate amplification for each. As well, I'm wondering if there was a reason for a 100/150 combination rather than 150/150 other than the obvious economic benefit.
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HG Cherry M60's,VP150,Qs8's,EP350

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#288164 - 01/22/10 01:12 PM Re: Two Center Channels [Re: Sloped]
Potatohead Offline
aficionado

Registered: 05/14/09
Posts: 670
Loc: Vancouver
Just run the wiring to one, and then from the first one red/black to the second one red/black.

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#288171 - 01/22/10 01:41 PM Re: Two Center Channels [Re: Potatohead]
ClubNeon Offline
connoisseur

Registered: 02/06/09
Posts: 3466
Loc: Western Maryland, USA
That's wiring them in parallel, and will, with two 6 Ohm speakers, present a 3 Ohm load to the amp. Some amplifiers, depending on playback levels may not be stable with that low of a resistance, and could go into shut down.

To wire them in series, you run the + from the amp to the + of one speaker, then the - of that speaker to the + of the other, and the - of the second speaker back to the - of the amp. That will make two 6 Ohm speakers appear as a 12 Ohm load. That'll decrease sensitivity (requiring an increased speaker trim setting). Plus the impedance curves of the two speakers will stack, resulting in a less linear response. So this is less ideal than the parallel wiring, but could be required depending on how the amp handles a 3 Ohm load.

The best option, is to run external amps. Split the line-out for the center into two separate amps (or two channels of the same amp), and let each drive an individual speaker at 6 Ohms. There'll be a slight voltage drop in the dividing of the line out, so the channel trim may need to be boosted a little; your SPL meter (or auto setup) will tell you how much.
_________________________
Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris

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#288176 - 01/22/10 02:01 PM Re: Two Center Channels [Re: ClubNeon]
CatBrat Offline
axiomite

Registered: 08/05/09
Posts: 6015
Loc: Milky Way Galaxy
Just curious. With two 6 ohms wired in parallel for a 3 ohm load, could you add a 5 ohm resister off of one of the wires between the receiver and the 1st speaker encountered? So that a total of 8 ohms are used. Or would this be disadvantageous?


Note: Disadvantageous is a word used by the "Disadvantageousness Club". Members only.


Edited by CatBrat (01/22/10 02:21 PM)

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#288179 - 01/22/10 02:14 PM Re: Two Center Channels [Re: CatBrat]
ClubNeon Offline
connoisseur

Registered: 02/06/09
Posts: 3466
Loc: Western Maryland, USA
The problem is, speakers do not have a fixed impedance throughout their frequency range. Adding a fixed resistance in series will change the response curve (just as wiring the speakers in series with each other does).

This is also why you shouldn't use very thin wire which offers too much resistance, as it will function to change the tone of the speaker.

EDIT: Oh yeah, 1000 posts! Done in less than a year.


Edited by ClubNeon (01/22/10 02:14 PM)
Edit Reason: 1000 Posts!
_________________________
Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris

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#288182 - 01/22/10 02:37 PM Re: Two Center Channels [Re: ClubNeon]
RickF Offline
axiomite

Registered: 02/26/05
Posts: 5210
Loc: Vero Beach, Florida
Sloaped I'm running a 100/150 combo only because of speaker upgrading from a small room into a larger room and that's what I ended up with. I wired mine in parallel for a 3.43 ohm load and have never had any issues whatsoever with our older 75wpc H/K AVR635 pulling that load in almost five years of daily use, although I am using a Rotel RB1080 pre-outed from the 635 for the mains (80s).

We're upgrading to a front projection system sometime this spring and then I'll probably get another 150 to match the current 150 but in the meantime the 100/150 combo is working perfectly fine and dandy.
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Our Room

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#288186 - 01/22/10 02:43 PM Re: Two Center Channels [Re: RickF]
CatBrat Offline
axiomite

Registered: 08/05/09
Posts: 6015
Loc: Milky Way Galaxy
One more thought projection on adding a resister. By doing so would change the response curve apparantly, but couldn't Audyssy, MCACC, or whatever, straighten the curve back out? So now you have something easier to power and a flat response?

Edited to add: Of course, that is if you like the results of using the EQ. Since currently I happen to like it, then it seems that would work for me.


Edited by CatBrat (01/22/10 02:49 PM)

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#288191 - 01/22/10 03:13 PM Re: Two Center Channels [Re: CatBrat]
Luke Smith Offline
buff

Registered: 01/13/10
Posts: 43
Loc: Brisbane, Queensland, Australi...
The resistor will waste and dissipate a lot of energy, and in the end will probably leave you with less headroom than the series config.

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#288193 - 01/22/10 03:25 PM Re: Two Center Channels [Re: Luke Smith]
ClubNeon Offline
connoisseur

Registered: 02/06/09
Posts: 3466
Loc: Western Maryland, USA
The resister isn't going to use that much energy, but the effect on the response curve may be enough that you'll use up most of the range of the EQ to try to recover from it. While a slight digital EQ adjustment may improve things, pushing it to its limits may start to show the weakness.

I'd just try the straight parallel, and see if it work. It may very well be OK. It's only toward the low end of the frequency range that the impedance drops.
_________________________
Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris

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#288198 - 01/22/10 04:14 PM Re: Two Center Channels [Re: ClubNeon]
Sloped Offline
veteran

Registered: 12/17/08
Posts: 110
Loc: Fonthill
Thanks everyone. I was aware of the different ways you can hook them up, I was more interested in why anyone went in a particular direction. I'll be hooking them up parallel since I've sold off all my external amps.

Now I like impressions of peoples perceptions and experiences of doing this configuration.
_________________________
HG Cherry M60's,VP150,Qs8's,EP350

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