The Scanspeak 12" bass drivers (30W/4558T00) arrived, they are fairly substantial drivers with cast alloy frame/basket and a large magnet.



I just used a library shot, but this is how they come.
I built some 55L sealed test cabinets, this volume gives a QTC of 0.707 and an f3 of around 36/38Hz.





I used 18mm chipboard for the construction of this temporary evaluation cabinet, with 18mm MDF for the front baffle and internal brace. All joints were rebated with a router for extra strength and the whole thing was glued without the use of screws or dowels. I used four cargo straps to pull it all up tight while the glue set.




Driver fits well and all joints pulled up without gaps. I loosely stuffed the cabinet, with a generous amount of fibre glass loft insulation. Need to get some hours on them now, before evaluating their performance.



Finished the second test cabinet and still running them in, one thing, there is bass a plenty.

SUMMARY AND CONCLUSIONS

So, I have tried the passive Quad Mid/Tweeter set up, paired with both the Yamaha 12" Bass and Scanspeak 12" Bass, crossed actively at 310Hz.
Each configuration had 150 hrs use before evaluation and were auditioned in my living room and in a larger setting.
The Yamaha version was used at the 2017 Hifi WigWam Scalford Show and the Scanspeak at the NEBO 8 bake off.

My concerns about the Scanspeaks ability to perform in the upper bass and crossover region were unfounded and it out performed the Yamaha in every area. Obviously from the specification, it would have deeper bass, but its noticeably a lot deeper, which gives a strong platform to work with. Its faster and tighter, not that the Yamaha is poor in these areas, but the Scanspeak is better and can only improve in a more rigid cabinet. The big surprise was in its upper region, where it is subtle and tuneful, blending seamlessly with the mid range. Comparatively the Yamaha is muddy and slow, not that I would ever have said that prior to the comparison, as I like the Yamaha's a lot.

The overall presentation of the speaker system using the Scanspeak is very enjoyable, it has depth and detail. The Ribbon Tweeter is very clean, not spitty like some and produces sweet highs. The mid range is musical and vocals are particularly well produced. It's by no means a tame sound and rock guitar riffs soar. London Grammars “Hey Now” has a deep droning bass note that typically sets rooms off, with this set up it has a cleaner more controlled sound with layering and depth in the note I wasn't aware of previously and my room doesn't complain in quite the same way because of it.

This combination of a pair of book shelf speakers, mated with a pair of sealed woofers instead of the usual single Sub Woofer, is something I had to try. The results in both my small, less than ideal room and in a much larger setting are very pleasing and its a sound I could easily live with. This is a milestone and a reference point, should I want to revisit and continue the development from here, maybe fully active?

I am now curious about how the Scanspeak 12” Bass and Fountek Ribbon Tweeter will work with the legendary Yamaha Beryllium Dome Midrange. This will be a fully active set up, call it NS-1000 revisited!
But that's another project.