How does room correction on an AVR work with an external amp?

[ChicagoLR3]

I am debating getting a Emotiva XPA-200 to power my mains (Aperion 6T). At present I am using a Pioneer Elite VSX-52 which is presently sending approximately 100 watts to each of my front three speakers (6T + 5C center). Since the 6T are 6ohm, I be getting around 190-200 watts out of the XPA, which is a significant jump over the AVR. Theoretically, since my receiver will only be powering one channel (center) it should be able to produce higher power, even if its not as high as the XPA. Will running MCACC on my receiver level this out? Basically, will it pull back the amplifier to balance with the center? At some point I would like to switch to a full 5.1 setup, which will change things once again.

I thought about getting a 3-channel amp to give each its own power, but XPA-3 don't come up used very often, and have more power than I probably need anyways.

Another variable is the sensitivity. The 6Ts have a 91db sensitivity, while the 5C is only 87 db. How will this impact it?

 

[KEW]

Yes, once you incorporate the amp, run MCACC and it should balance levels for you.

 

[ChicagoLR3]

I get that part, but since the amp is stronger than the AVR will this result in me not being able to take full advantage of the amp? Will they basically equalize somewhere between the two?

 

[WaynePflughaupt]

At present I am using a Pioneer Elite VSX-52 which is presently sending approximately 100 watts to each of my front three speakers (6T + 5C center). Since the 6T are 6ohm, I be getting around 190-200 watts out of the XPA, which is a significant jump over the AVR.

It’s not that significant. Doubling power only nets a 2-3 dB increase in SPL. You pretty much have to quadruple power to get a “significant” increase.

I take it that by “leveling out” you don’t really mean matching the speaker levels. If MCACC “pulls back” the Emotiva amp to balance speaker levels, that only means it’s reducing its input signal. That has no effect on the amplifier’s maximum output. It only means the pre-amp must be turned up more for the amp to deliver its maximum output.

It’s tough to definitively quantify your question since we’re dealing with different speakers, but maybe this will help: If your center and main speakers were matching, what you’d “benefit” with the external amp is this: At the point where the center channel amp ran out of steam and started clipping, the L/R would have a few dB more headroom. I put “benefit” in quotes because it should be evident that there is no real benefit if your center channel is clipping while the L/R speakers maintain clean output.

Your real “balance” situation is that you have a speaker with 87 dB sensitivity powered with a 100 watt amp, and speakers with 91 dB efficiency powered with a 200 watt amp. Things would be more “balanced” if the two were reversed.

Regards,
Wayne A. Pflughaupt

 

[j_garcia]

NO, you will NOT be pulling 200W when using your speakers. They will be capable of drawing that much, but to actually play at normal listening levels you will be using only a small amount of the amp's power on a regular basis. PEAKS may see spikes in draw, but not sustained. The receiver still calibrates to the same level regardless of how much draw you have.

 

[PENG]

I get that part, but since the amp is stronger than the AVR will this result in me not being able to take full advantage of the amp? Will they basically equalize somewhere between the two?

First of all, balancing the L/R to the center will not result in not taking full advantage of the amp. If the amp is in fact more powerful than the AVR, it only means if you keep turning the volume up, the AVR will distort/clip sooner than the amp but it won't limit the output of the amp at all.

Secondly, based on the following information, I would say if the Pioneer is driving only the center channel, it will be as "strong" as, or even "stronger" than the XPA-200. The XPA-200 has unusually large capacitors, in factor 50% larger (in terms of capacitance) than those in the XPA-3 so it is going to do better in providing short burst of power. I also wonder if Emo had a typo in the specs. Other that, I am quite sure the Pioneer has a much larger power supply than the XPA-200.

VSX-52

http://www.soundandvision.com/content/pioneer-elite-vsx-52-av-receiver-ht-labs-measures#G80IoObtduBwWRb7.97

"This graph shows that the VSX-52’s left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1 percent distortion at 108.7 watts and 1 percent distortion at 136.8 watts. Into 4 ohms, the amplifier reaches 0.1 percent distortion at 164.5 watts and 1 percent distortion at 211.2 watts."

XPA-200

150 watts / channel; into 8 Ohms; both channels driven.
240 watts / channel; into 4 ohms both channels driven).

Power Supply:

• 90,000 uF of low-ESR storage capacitance.
  360 VA heavy duty toroidal transformer.