Here follows an extract from my 3805 manual, I would expect the 4306 to be similar:
NOTE:
• Select “Large” or “Small” not according to the actual size of the speaker but according to the speaker's capacity for playing low frequency
(bass sound below the frequency set for the Crossover Frequency) signals. If you do not know, try comparing the sound at both settings
(setting the volume to a level low enough so as not to damage the speakers) to determine the proper setting.
Large...................Select this when using speakers that have sufficient performance for reproducing bass sound below the frequency set for the
Crossover Frequency mode.
Small...................Select this when using speakers that do not have sufficient performance for reproducing bass sound below the frequency set
for the Crossover Frequency mode. When this is set, bass sound with a frequency below the frequency set for the Crossover
Frequency mode is sent to the subwoofer.
None……............Select this when no speakers are installed.
Yes/No….............Select “Yes” when a subwoofer is installed, “No” when a subwoofer is not installed.
2spkrs/1spkr .......Set the number of speakers to be used for the surround back channel.
If the subwoofer has sufficient low frequency playback capacity, good sound can be achieved even when “Small” is set for the front, center
and surround speakers.
The point is that the Bose speakers roll off from 280Hz and have no capability below the 80Hz crossover, whilst the subwoofer won't kick in until the cross-over frequency. So you would be better off raising the crossover frequency a bit. The key issue I was trying to point out is that if you use the auto-configuration then the amp does some correction for equalisation and will boost bass to the small speakers. As I said this can lead to very high power and burnt out coils. I know because I did this to a pair of Energy Encore speakers. Denon support was very helpful, whilst Energy did eventually admit the auto set-up could cause a problem but they haven't included a warning in their set-up instructions yet. I got partial compensation for the repairs!
If you go with large I suggest you check what the amp sets for equalisation after the calibration and beware DVDs with deep bass (especially the beginning of Blade 3 where the subway noises are intense). You can compensate for bass by increasing the sub-woofer volume.
The manufacturers of small speakers claim that large is ok because it usually is but the auto equalisation of the Denon upsets things.
