Upgrading a 5.1.2 Setup that Has Bi-amped Front L/R Speakers

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Q I have a 5.1.2 setup based around an Onkyo TX-RZ840 receiver and a Monitor Audio Bronze speaker package using the Bronze 2 stand mounts. My left and right front speakers are bi-amped. My media space is 14 feet wide by 13 feet deep and I’m looking to upgrade to 5.1.4. My inquiry is twofold: I wish to add an Emotiva BasX A5 and A6 as external amplifiers plus a Denon AVR-X4700 or Marantz SR-7015 AV receiver in preamp mode or a Marantz 7706 preamp processor. In principle, the 7706 would provide the best audio quality, but given the size of my media space and the speakers I’m using, would I get a worthwhile upgrade in audio quality choosing the 7706 over the Denon or 7015 in preamp mode?

Secondly, is the pre-output voltage in this equipment a good match with the Emotiva amplifiers? I read an excellent article in your magazine explaining the relationship between the pre-out voltage from the receiver/processor and power-amp gain, but I’m not sure how and where to check. Would a receiver and a power amp serving the LCR speakers and the receiver amplifiers looking after the four height speakers and rear surround speakers provide good results? —Dan Pinnock, via email

A There’s a lot to unpack here! You didn’t give your room height, but assuming an 8-foot ceiling, your room is 1456 cubic feet, which is on the smaller side. (This is exactly in the middle of a THX Certified Compact and Select room size, by the way.) Your Monitor Audio Bronze 2 speakers have a nominal impedance of 8 ohms, a sensitivity rating of 90 dB, and a maximum power rating of 100 watts, so any of the options you suggested will provide plenty of power and performance.

While both receivers can support bi-amping your front speakers, doing so will limit you to a 7.1.2 layout, not 5.1.4 as you plan, as the bi-amp connection requires using the Height 2 speaker connections. Both the Denon and Marantz AVRs have similar rated power amplification (125-watts, 8-ohm, 20 Hz–20 kHz, 0.08%, 2-channels driven), with a “70% power guarantee,” which the company defines as “a minimum of 70% of the stereo power indicated in the specification section will be available when 5 channels are simultaneously used.” The Emotiva BasX has similar power ratings (120-watts, 8-ohm, 20 Hz–20 kHz, <0.02%, 2-channels driven; 95-watts RMS per channel, all channels driven, <0.1%). So, I’m not sure how appreciable the performance gain would be by using the Emotiva amp(s) over the AVR’s internal amps.

Regarding the Pre-Amp Mode on those receivers: This feature disconnects the internal amplifiers to provide a clearer signal path and more tolerance in clipping levels. However, this is an all-or-none feature; using Pre-Amp Mode means bypassing all the internal amplifiers.

Ultimately, it really depends on your budget. If you have the means, get the Marantz AV-7706 and both the Emotivas, as this will be the basis for an excellent system. Otherwise, I’d get the SR-7015 and have it drive all of the speakers, with the upgrade path of adding the Emotivas later. However, I feel compelled to tell you that both Denon and Marantz displayed new models at CEDIA (Denon AVR-X4800 and Marantz Cinema 40). The big difference is that both AVRs support up to 11.4 channel processing with four independent subwoofer outputs, the option to disconnect internal amps by specific channel pair on top of the all or nothing pre-amp mode, and future upgradability to Dirac Live room correction.

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adrianbyrne's picture

Can someone tell me about the sound and price of these high-frequency speakers I am thinking to buy a new speaker set and dispose of the old one. Well, I am the CEO of CV help agency in ireland and I liked the informative content of your website.