One sub, a two channel system ,one HT reciever ??

Rolling off their bass may enable them to play louder but when I have tried it I found the benefits mostly theoretical and the drawbacks obvious.

One of the obvious problems from removing copious amount of bass distortion is that you can now hear copious amounts of lower midrange distortion or you may hear the obvious dull compression of the midrange. Often these effects are hidden by bass distortion. Masking effects on the ear do work in a designers favor...a ported resonant and harmonically distorted bass with a lousy impulse response can hide a lot of other shortcomings. This is not well understood but as a consequence modest amounts of distortion are often regarded as pleasing - making the music flow and sound more natural by hiding the obvious midrange blemishes of a poor design. This may be one of the reasons it is so hard to match a subwoofer to a panel...since a good panel has very low midrange distortion it sounds worse when masked by the subwoofer (contrary to a normal speaker that benefits from added bass distortion: think your average car stereo which sounds pretty good despite all the distortion)

Bob , without getting personal I would like to ask if you have ever heard ANY of the equipment I have described. I am describing experience, you are mouthing platitudes The Spendor , for example , was designed by the BBC and used around the world by other national radio networks as monitor speakers. The Nelson Reeds were designed as monitor speakers for movie studios. I probably made a mistake posting on an AV Question as the performance parameters appear to quite different. I was a Quad dealer for over 20 years and of course they are famous for distorted sound. Note to self, no more AV postings.

I was a Quad dealer for over 20 years and of course they are famous for distorted sound.

Do I detect some tongue-in cheek?

I would add that anyone with a typical modern system where it is often difficult to hear dialogue on movies without jacking the sound way up (background sounds cloud diaglogue) needs to ask themselves what might be wrong with their midrange and what might be wrong with the "impressive" bass....one word "distortion".

Thanks all

What worked was to run the Kef 104.2 full range. I used the Kube 200 active equalier to extend the kef 104-2 base range and the second line level output of the Kube to send a second independent line level signal to the Velodyne subwoofer. I set the low pass crossover to about 60 Hz which gives me the missing bottem octave.

More playing to do but I am making progress.

I suspect with a better quality sub that I would have more options since this sub vibrates or buzzes if I set the cross over too high (80 hz).