I'm not looking at the watts for 8 ohms I'm looking at the 4 ohm watts. Plus it has nothing really to do with the watts, my concern was whether the Denon 3806 receiver was 4 ohm stable. Meaning can it handle 4 ohm loads for extended periods of time under normal to higher volume.
That is a nice receiver, back in the day one of the best. I just hate to see you damage it.
Put it this way, if the Denon is rated 120 W into 8 ohms, it will be rated at least 60 W into 4 ohms. For real world music and movies, it will be able to do more than 120 W into 4 ohms and stable, but the issue would be if it is used to play compressed music for extended periods it will overheat and hopeful shutdow before it cooks itself to well done.. As always, the safe bet would be to use the online calculator that has been linked many times. The calculated numbers would be based on 8 ohms, but you lower the entered speaker sensitivity by 3 dB and the results will then be good for 4 Ohms. Or use the specified sensitivity, but whatever "watts" you entered, once you get the targeted spl, half it and that would be the correct number. I think you know that very well already..
Peak SPL Calculator (homestead.com)
Regardless, for use with 4 ohm load, I would put a fan on top.
Below is the linked to the AVR-3805 test I mentioned earlier, that it passed the 1 ohm test:
Report (milleraudioresearch.com) Note: No sign up required
The 3806 was also tested, but only down to 2 ohm, they did not do the 1 ohm test on it:
Report (milleraudioresearch.com) Note: Any tests results after 2004 required sign in, but it is free to join.
Again, those low impedance torture tests were measured obviously based on some dynamic output measurements standard/protocol. If you use the thing on 4 ohm nominal speakers and expect the same 8 ohm rated maximum output for extended period, then it is a different story. For such use you really should use the calculator to find out if the 3806 would be up to such a task.
Bottom line is, the 3806 is quite powerful, and for 2 channel use I would think it is comparable to something like an Outlaw 5000/7000, or Emotiva A-300.