Should I Use the Outboard Amp in My 7.2.4 Setup for Front L/R or Atmos Speakers?

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Q I have a 7.2.4 home theater with a Marantz SR7015 AV receiver powering 7.2.2 of the 7.2.4 speaker setup and a Marantz MM7025 stereo amp powering two of the overhead Atmos speakers. I can’t exactly remember why I decided to wire it this way, but I’ve since wondered if it would make more sense to use the MM7025 to power the two front speakers rather than two of the Atmos speakers. Or does it not matter? Would it alter the Audyssey calibration process (which obviously I would run again after changing)? Are there any disadvantages? Thanks! —Mike Antoniello

A Great question, Mike, and a situation I’ve personally encountered on several installs! With the generation prior to your Marantz SR7015 — the SR7013, and even the newer SR6014 — when driving an 11-channel system such as you describe, you are only able to power the Height 2 speakers using an external power amplifier such as your MM7025. Frankly, this is a real waste of potential as most systems have higher performing and more demanding front/main speakers compared to whatever is connected to Height 2. Not to mention how much more signal those front channels receive — especially if you’re a music lover — compared what is sent to the Height 2 output.

Fortunately, Marantz made a change with the 7015 Series, and when using an 11-channel speaker system, you can assign the output to either the Front (main left/right) or surround Height 2 outputs. (You can find this under the “Amp Assign” section of your Marantz’s owner’s manual.) Of course, you can still connect an external amplifier to any of the other pre-outs to power other channels if desired.

While the power ratings between the SR7015’s amps (125 watts/channel) and the MM7025 (140 watts/channel) are similar, the MM7025 wouldn’t be sharing its power supply across all of those other amplifiers so it should have more power reserves to deliver more dynamic peaks when called on. Also, by off-loading that power to the outboard amplifier, the SR7015 would have more dynamic potential for the other channels it is powering.

There are zero disadvantages to this approach, however, I’m pretty sure that once you make the configuration change in the Marantz’s amp settings, it is going to force you to re-run Audyssey if you want to use it. But this would give you a perfect opportunity to try out the Audyssey MultEQ Editor app on your mobile device, or the new MultEQ-X PC app!

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