Thanks for the responses so far. I posted a lot of questions, so there is a lot to respond to for followup/clarification. I'll keep the same format.
1. I was looking for models that are good, not so much brands. Trane makes a line of Hyperion AHU that are advertised as "ultra quiet", but that's a lot like "reduced fat". It's all relative. I haven't found any noise specs. The Hyperion XL has variable speed fan and when paired up with their XL20i heat dual compressor heat pump, it will supposedly run lower speed and quieter when it can. But I thought an axial fan would be quieter, so I might try to get something engineered from their commercial side. The commercial side has acoustic modeling software (TAP).
2. Trane (Honeywell) makes a really cool thermostat seen here: http://www.youtube.com/watch?feature...&v=9VQ3Fs8PQGU
3. Less holes in the aquarium makes sense. I just thought since the ducting itself can have noise associated with it, it might make more sense to keep that outside of the isolation envelope. I also wondered if a mini-split located inside of a soundproof soffit would make any sense. Mits has some 19dB mini splits.
4. With dual zone, the variable speed fan shouldn't require dumps. For the same money I could also trick out a single AHU better than two dedicated systems - i.e. add filtering, ERV, nice tstats, etc. But I was told the dampers themselves, when closed to only supply air to the HT, would cause noise from the air bouncing off them. But I'm not sure how much that really matters.
5. It's new construction, so if I used a dead vent I would size the exterior of the theater to handle the heat load of the interior. I'm just wondering if dead vents are quieter than running dedicated supply & return ducting around the inside of the HT (from the AHU). In other words, when designing a room from scratch, are dead vents a better approach than a conventional "ultra quiet" central forced air HVAC system?
6. For ERV, I meant one attached to the furnace. Like Trane FreshEffects. My understanding is it's built into the return ducting to exhaust a portion of the stale air, and replaces with fresh air.
7. My plans call for over sized ducts, and similar has been quoted here as de facto AVS standard, similar to GG & DD for walls. I think larger ducts reduce static pressure for a given CFM, which should reduce noise, and that's where the recommendation comes from. It may also be to build in some breathing room since the guys on the ground often make a lot of compromises during install.
8. The comfortlink II thermostat has controls for humidity. The AHU has options for hydronic heating. The ERV is also suppose to help humidify in winter (by retaining the moisture present in the fresh air). I think I will only address high humidity, which the AC system can do on it's own fairly well without needing a dedicated humidifier/dehumidifier.
9. The requirement for -30F has also become an AVS de facto HVAC recommended standard.
This goes back to my original question, are people here actually following the recommendations/designs they receive? Not once have I ever seen anyone question, why -30F? That's a significant upgrade to be able to hit that number. So much work goes into wall design - clips, glue, and even discussion about which model screws to use. When it comes to HVAC, it's basically a NC noise requirement, with a few commercial standards for air quality, some best practice advice, and general acknowledgement that it's unlikely your typical residential HVAC guy will be able to achieve those requirements.
10. Everyone likes flex because it's easy to install. I'm just not sure it makes sense in the context of HT. After you've done special framing, clips, channel, 2 layers of drywall, and got smelly green glue all over everything... does 'ease of installation' for the HVAC lines really matter?