And yes, thanks to your excellent post above I am now clear on the gain matching issue. It's for sure something desirable to have but not essential for proper performance and a fantastic experience.
That's very true especially if you want to achieve that in a full blow combined HT/music system. To achieve near perfect gain matching you would have to consider every piece of gear in the signal chain, the speaker sensitivity and your listening habits. Even if you can do it you may gain a few dB lower in the overall THD+N from input to output. Based on the information you have provided so far, the Trinnov will likely output between 1.6 and 1.7 V to drive the Outlaw 7220 to its rated 220 W into 8 ohms and I would estimate about 1.4 V will drive the Outlaw 5000X to also about 220 W into 8 ohms.
If you are currently listening with the SR7009 at between -8 and -15 then I would estimate your pre out voltage will not exceed 1 V or even 0.7 V most of the time, except during the highest peaks on the content and/or when you crank the volume to 0. Since the Outlaw amps seem to maintain the
same input sensitivity** for both balanced and unbalance input, when you use the Trinnov, the pre out voltage will most likely remain the same as that of the SR7009. That is actually very good because it means you can be sure even if crank things up to get reference level spl, the Trinnov will never get close to its clipping point. For even better gain matching, the Hypex or Purifi amps will be better as they have about 3 dB lower gain than the Outlaw amps so naturally you will get lower noise. Then again, going from say -85 dB THD+N to -105 dB seems like a lot, but it will not likely make any audible difference. I don't know what the min/max volume is for the Trinnov, if it is the same as the SR7009 (it most likely is
not the same), then you can expect lowering the volume dial from your current -8 to -15 to about -13 to -21.
** Many power amps such as Marantz (even some older ATI or Outlaw amps) have 6 dB (typical) lower gain for their XLR input to compensate for the higher (2X) voltage.
By the way, as you already know, there are other thing to consider gain matching is that it depends on what kind of scenarios one is thinking for best matching. Take a look of the following scenarios:
a) when I say your SR7009's pre out will be below 0.5 V most of the time, keep in mind that is average, not peak (let's stick with rms regardless). For example, when watching a THX standard movie such as the Star War series, the AVR may output between near 0 to 2 V, and averaging say 0.2 V for you to hear 85 dB average, then during the maximum peak level at 105 dB, the pre out might have to peak to a whopping 2 V! Under the same scenario, the Trinnov would output about 4 V, because the ration XLR to RCA is 2:1. So suddenly your perceived gain matching looks much closer right? That is, about 6 V rated, and it is actually reaching 4 V during the 20 dB peaks in the movie, so the Trinnov would still have some headroom but not excessive any more. Its a little complicated, not black and while that can be described or defined in one sentence.., though of course one can generalize..
b) this one is obvious, now you have an Outlaw amps with gains about 28 and 29.7 (based on Gene's measurements on the older 5000 model), but there are many excellent power amps that offer much lower gains. For example, the currently best measured Benchmark AHB2's gain is selectable, from 9.2 dB to 23 dB and the second best measure amp would be one of those Purifi based amp that has about 25 to 26 dB gain so you can see that if one has a rule to say match the preamp and power amp gain a certain way, one would have either relax that rule, or replace not one but both amps.
Just learning the ins and out of the Altitude will be a beast all on its own though...so wish me luck, lol.
I do wish you luck, but in reality, what you might need more is time, to thoroughly read the owner's manual, do the setup properly to optimize all settings and get the best out of the supposedly excellent Room EQ software.
Have fun, for that kind of money you deserve to have lots of fun setting that new toy up.
Edit: Forgot to ask, does the Altitude 16 has HDMI 2.1/8K, if not, is it upgradable? If you are sure it is not something you want then it doesn't matter.