Purité Audio's first pair of Dutch&Dutch loudspeakers arrive this week, their 8C model, Martijn Mensink is D&Ds acoustician and designer of the 8C,we were discussing the specification of the 8C and whether the addition of a subwoofer would be beneficial even though in standard form the 8C extends down to 20Hz at only -3dB, below Martijn's reply.
In theory the advantage of a cardioid is that it excites more modes (it is both a velocity source and a pressure source), whereas a dipole (velocity source) and a monopole (pressure source) excite fewer modes but transfer more energy to them. In my experience this might indeed be an advantage, but it is very room dependent and the room itself remains the dominant factor. I've had good and less good results with monopoles, dipoles and cardioids for bass. In my view the greatest advantage of a cardioid in comparison to freestanding dipoles and monopoles is that they are less sensitive to placement. Especially if you have one main listening position and the ability to EQ, all three can sound great. Clearly the greatest advantage of a cardioid is in the upper bass and lower midrange, where discrete reflections lead to comb filtering and audible coloration.
What I like about the multisub solution, is that you it allows you to actually cancel modes. The bass becomes even tighter and improves throughout the room. It is my preferred solution in terms of sound quality, but a lot less practical than just having two speakers. The 8c with its boundary coupled woofers and a bit of EQ to tame the biggest peaks sounds very nice and tight by itself, but by adding two subs you have the potential for even better bass. The issue is that they are relatively difficult to set up properly and many people are biased against subs for music in general. '
I must admit up to this point I had only considered using sub woofers as additions to extend the bass response of main speakers, I had considered the use of multiple subs to destructively drive a room as the preserve of multiple seat 'cinema' implementations.
Adding and configuring a couple of active sub woofers would be simple enough using an Illusonic processor.
Dutch&Dutch's 8C's arrive soon ,subjective and in-room measurements will follow.