Dual center channel Speakers

dldvision

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I want to run dual center channel speakers. I understand that when you remove the jumpers from a nominal 8 ohm speakers, you now have two separate nominal 8 ohm speakers (high and lows). Now I connect those terminals in series so I should have a single nominal 16 ohm speaker.

What is the downside?

The specific speaker is Klipsch RP-504c.

Now I connect a separate nominal 8 ohm speaker in parallel, for example, another RP-504c. From the amplifier's perspective, it sees a nominal 8 ohm speaker?

What is the downside?
 
If you think about it, the downside is that the tweeter wiring/crossover is designed for a much lower rated power level. You will be effectively passing the power required to drive the woofer through that wiring/crossover - i.e. not advisable and probably won't work! Also the speaker impedance is a TOTAL of both drivers and crossovers - each one separately could have a different impedance.

If each speaker is 8 Ohms, just wire them in parallel to give a 4 Ohm load to the amp or in series to give a 16 Ohm load to the amp.
 
Not quite the whole story.

The tweeter side is connected via the crossover so only (mostly) loads the line for the tweeter frequencies, same for the woofer so it's not just two 16 ohm loads in parallel, it two 8 ohm loads that operate at different frequencies, in parallel, so back to ~ 8ohms again.

The tweeter is usually DC decoupled via a capacitor so not only might you blow your tweeter you would find very little or no output from the woofer.

The final part is it's likely you will need a slight difference in timing between an above screen center and a below screen one, depending on screen size and position so you would need a separate processor out to drive it or at minimum something like a minidsp. Probably the channel EQ would need to be different too, especially if you have dirac.

So try it with separate amps or parallel if your amp is happy with 4 ohms but unless your AVR or processor has capability to process a center height channel, I think you won't find it works well.
Auro 3D does this I think, Trinnov can, maybe others, I gave this a go once many years ago and it sounded horrible.
 
Thanks for the information, I really appreciate it.

I recently installed a Sony XBR-AG9 OLED TV with Acoustic Surface + and decided to ditch my sound bar (TV sits only 1/4" off the surface of the stand). I purchased a Klipsch speaker setup without a center channel speaker because the TV has "Center Channel Mode" where the TV speakers are driven by the "Audio System", in my case a new Sony STR-DN1080.

When the speakers arrived, I setup a speaker AB switch and tested my RP-600M book case speaker under the TV against the TV Speakers. It was clear the RP-600M sounded better, at least most of the time, but what sounded best was using both the TV speakers and the RP-600M in parallel. When using both, the sound appears to come directly from the screen and is overall more natural.

I have now ordered a RP-504c center channel speaker and plan to do the same test again. Assuming the same result, my plan is to run the 4 ohm speaker setup from the center channel output of the receiver and hope the receiver handles it. I rarely play at high volumes and will avoid clipping in any case.

Sony, if you are listening, you should have allowed the Zone 2 outputs, most often unused, to mimic any of the 7 standard speakers, then I would be golden! There is mode where Zone 2 uses the same source as Zone 1, but I assume they mimic the left/right channels in this case.
 
Friendly thread bump here...lol.

I posted this over on a few other forums, but I wanted to post it for discussion here as well. One of the new specs being touted about the channel layout for the DTS-X Pro and IMAX Enhanced soundtracks is the 'Center Front Height' channel, and this has piqued my interest..

Many, if not most, home theater enthusiasts suffer from some sort of compromise when it comes to locating their center channel either below or above their screen, so this new spec surprised me and I'm wondering about it's potential implications.

From the meager amount of info I've been able to find online about the purpose and function of the Front Center Height channel, it sounds like they decided to implement a sort of 'dual center channel' approach. There are a couple of YouTube videos where the Sound United guys talk about the speaker layouts for IMAX Enhanced and DTS-X Pro (and Auro), and the IMAX theater screens were mentioned as the original motivation for their need to implement 2 center channels, because the IMAX screens were so large. That concept then got adapted for the home environment and they mentioned using this new Front Center Height channel as simply another discreet speaker in the setup, and that it used phantom imaging between it and the other speakers nearby (L / C / R / and Wide spkrs) to better lock the sound to the screen.

Historically, the dual center channel approach has been frowned upon and is cautioned against because of the potential for comb filtering, lobing and other negative side effects (which I agree on). The forums and threads covering this topic all mentioned one explanation for why doing dual center channels was a bad idea, and that was 'if it was so easily done and such a reasonable approach then one of the big companies would have done this and just added a 2nd discreet center channel above the screen'. It seems to me like this may be what has happened here with the CFH channel approach by IMAX and DTS.

I may very well be wrong in my interpretation of this channel's use, but I'm curious what everyone's thoughts are about it and it's potential, considering that it would solve the center channel localization problem that so many people have.
 
There are current products that already support a "centre height" channel and have done for a long time, not sure if you're aware @cheyneb25?

E.g. from AVC-X8500 manual:

1647942370585.png
 
There are current products that already support a "centre height" channel and have done for a long time, not sure if you're aware @cheyneb25?
I was aware that Auro had done something along those lines, it just sounded to me like the IMAX Enhanced and DTS-X Pro formats were handling the implementation of that channel a little differently than Auro was, but again, I could be wrong. I frequently am with many other subjects, lol.

I guess I was just really interested and surprised to see that someone was trying to do some variation of the dual center channel idea by using another discrete channel above the screen. What are your thoughts about using a 2nd discrete center channel located above the screen to better lock the sound to it?

And here are the 2 YouTube videos I was referring to where they talk about the CFH channel.
- between the 8 and 9 minute mark
- CFH channel mentioned intermittently
 
I was aware that Auro had done something along those lines, it just sounded to me like the IMAX Enhanced and DTS-X Pro formats were handling the implementation of that channel a little differently than Auro was, but again, I could be wrong. I frequently am with many other subjects, lol.

I guess I was just really interested and surprised to see that someone was trying to do some variation of the dual center channel idea by using another discrete channel above the screen. What are your thoughts about using a 2nd discrete center channel located above the screen to better lock the sound to it?

And here are the 2 YouTube videos I was referring to where they talk about the CFH channel.
- between the 8 and 9 minute mark
- CFH channel mentioned intermittently


My thoughts are (1) if the second speaker is a "centre height" then it has it's own channel and will be processed, EQed, time aligned by the AVR or processor. If (2) it is another speaker outputting the centre channel signal then my thoughts are the same as @AndreNewman above. You'd need something on the output such as a MiniDSP so you can time align the two centres together. And even then you may find it just doesn't quite work.

Speech is not only the most important part of the soundtrack but also the bit that the human ear is most tuned to. Tiny differences in alignment of the sound between those two speakers (and remember they won't always sit in the same off-axis too - your MLP can be two inches up and you've just changed those vertical angles) could be very irritating.
 

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