HVAC: Need help RE-designing. HRV not effective.

Hello, I have had a HRV installed for ventilation of my Seattle studio, it has been ineffective as my studio often feels hot and muggy, esp with 4 or 5 musicians in here, with gear on. The original design is this: I have two 8" hard ducts coming from my garage (getting air from the outside), via a Heat Recover Ventilator into my studio, then splitting via a plenum to four 8" soft ducts (one for fresh, one for exhaust, for each of my two rooms). I am looking to have the 320 cfm HRV replaced with two higher power fans. Having the air coming in, be the temperature of the outside air would be better than the HRV (which heats the incoming air with the exhaust of the hot room), but ... ...I also want to see if an AC exists that can feed ducting, inline (with say a 4" duct going straight into the incoming vent's duct. Is this possible- do AC's exist that send cool air through a duct? I am hoping I can have a small AC in the garage feed the ducting so I can manually turn that on to get some colder air coming in when it gets too hot. Most of the time the straight fresh air from the outside would be all i need. So- 3 questions. 1. How many CFM can I push through an 8" hard duct that is about 4 feet long, then spitting into two 8" ducts (8 feet hard, 8 feet soft? 2. Does an AC exist that can feed a duct? 3. Any recommendations on quiet, powerful fans? (I have been looking at the Panasonic Whisperline, but open to suggestion). Thanks, Evan Schiller

Any good recommendations for quiet, powerful ventilation fans? I'm looking for around 500 cmf, best cfm to sone rating I have found is the Panasonic Whisperline FV-40NLFI, which is 440 cfm at 2.1 sones. I'd ideally have more CFM than this, but need to keep the sones down pretty low. Thank you for any recommendations! Evan