The Dutch & Dutch 8Cs have been here a couple of weeks now and I have been experimenting with placement, Martijn ( chief acoustician) recommends placing them close to a rear wall ideally between 10cm and 50 cm, he said that it would improve the 'punch' from the bass and he was correct!
There are boundary settings for both rear and side walls, the speakers can also be used 'free field', 70cm free space is recommended to each side of the speakers, this enables the cardiod response to be most effective, D7D state a 15dB reduction if used optimally!
I positioned the 8cs and the Kii THREEs in the exact same position and measured both speakers from the listening position.
The Kiis are in green and the 8cs in magenta, as you can see the plots are incredibly similar and both are spectacular!
The dip at 200Hz might be a room mode or a discrete reflection, I don't consider it important I would be far more concerned with a significant peak.
I placed some traditional ,well respected active loudspeakers in the same position and also measured those.
Blue is the traditional speaker!
Martijn is translating his 'explainer' into English but in the meantime he sent me some advice regarding room acoustics and the 8cs.
Below 100 hz: The room is dominant. Speaker type has some effect on mode excitation, but positioning of speakers and listener are more important. Steady-state response at the listening position strongly correlates with what we hear. Use the DSP to fix peaks.
Between 100 and 400 hz: Discrete reflections are dominant. This is where a cardioid has its greatest advantages over conventional speakers. Correlating measurements with what we hear is most difficult in this region. Be careful with using the DSP to fix peaks and dips, you might make things worse.
Above 400 hz: The speaker is dominant. Look for a speaker with flat and smooth response and even dispersion. If the speaker is of high quality, don't use any EQ to fix peaks and dips in the response. What you might do, is apply some subtle global EQ, for example to reduce the treble a bit in order to compensate for a lively room.
Floyd Toole explains this stuff very well in this video (over 1 hour!): https://www.youtube.com/watch?v=zrpUDuUtxPM
More measurements and how the 8cs work to come!
This was the Kii THREE measured in the same position,