I'm running 208s in an approximately 4500 cu ft room with 800 wpc into 4 ohm for the front stage (the 208s dip down to ~3.7 ohm per Amir's measurements), but I think that's way more power than I'll ever need. I think 400 wpc into 4 ohm will be more than enough unless you plan to open the windows and play a concert for your neighbors. The only thing I would make sure is that amp is rated at full bandwidth, not something like 1khz. If it puts out 400 wpc into 4 ohm continuous with full bandwidth and low THD, then I think you're good to go!
On the question of 208s vs. 206s, I auditioned the 206 at the dealer and ended up with the 208. The 208 renders a larger soundstage with more perceived depth because of its mid/low output. Everyone here told me go 208s and I'm glad I did. They are the best speakers I have owned.
I had the same question when I bought the AHB2 and drove the Salon2s with a single AHB2 in stereo mode.
Aquaman BD played loud (to our tastes) was putting out some serious bass and the AHB2 was not clipping.
This was puzzling so I decided to measure my Salon2s at my listening position to get a power baseline.,
A stereo sine-wave at 0 DBFS 1Khz (also 2kHz and 205 Hz) and 2.83 volts produced 86 dB at my listening position.
The Salon2s are basically 4 Ohms so that computes to 2 watts. With that as a base, I plugged that into a spreaksheet to compute the maximum power usage at volume levels labeled to match my habits.
With digital signals, these are the maximum power at each Volume setting.
This may be too complex for most but it is an accurate measurement of my power requirements.
The problem with power calculators is it is easy to be off by 4X.
Here is the crown calculator for power required for 101 dB.
This is one speaker so, for two cut it in half and that is 445 watts versus the measured power of 64 watts. The crown calculator over estimates by over 7 times.
Here is a better SPL calculator for 2 speakers with the most optimistic settings for gain, 86 dB (though at 4 Ohms it uses 2 watts), my speakers are not really in the corner but it gives more gain.
Peak SPL Calculator (homestead.com)
With optimistic settings, this calculator computes that 101 watts produces 104.5 dB at the listening position.
This calculator shows that100 watts produces 104.5 compared to my measurements where 100 watts produces about 102.5 dB (eyeballing it).
Basically, a normal seating position with 2 speakers reasonably close to the rear wall are going to deliver about the same as their sensitivity ratings at 10 feet in most rooms. This calculator (Peak SPL Calculator (homestead.com) ) is pretty good with "In Corner", in my case, even though the Salon2s are not stuffed into the corner but are within 2 feet of the rear wall.
- Rich