IX, it appears that you are way stressed out on this decision. First of all, if the 3801 has inboard amps for all the 7 channels then.....you do have a great start and use those amps.
To worry about THX/DTS......don't worry about it. The Denon is more than capable to faithfully deliver the intended soundtrack. I use a Meridian 861 and never use the THX (enhancements?) except for logic material.
You may want to go with the 4800 or 5800 if it improves upon the D/A stage, and that you are a critical listener. That's for you to decide. You can however improve upon the sonics by adding a multichannel high-end external amplifier/s to the mix.
So your answer isn't as simple as you asked because you can go in many directions to achieve the sound that you want.
How much do you intend to spend to get the performance that you seek?
To worry about THX/DTS......don't worry about it. The Denon is more than capable to faithfully deliver the intended soundtrack. I use a Meridian 861 and never use the THX (enhancements?) except for logic material.
You may want to go with the 4800 or 5800 if it improves upon the D/A stage, and that you are a critical listener. That's for you to decide. You can however improve upon the sonics by adding a multichannel high-end external amplifier/s to the mix.
So your answer isn't as simple as you asked because you can go in many directions to achieve the sound that you want.
How much do you intend to spend to get the performance that you seek?