It would be interesting to know the CMS (Compliance) measurement of that 8" NQ driver. Over the course of playing with quite a few speakers / drivers... I think I may have stumbled upon why one woofer driver sounds better thru its midrange than another, and what that means for its low end output.
I am experiencing it right now between different speakers / drivers... and it's influencing the choices I'm making. Using the M165NQ in the Merlin VSM in place of the Scan-Speak 8545 was a revelation, and I think I know why.
The M165NQ has a lower CMS / Compliance measurement (.723 mm/N), so it's a "tighter" driver, which means it can play clearer up thru the midrange. That's why the curve is so nice, and probably contributes to it only needed 2 parts in the network for the low end. It naturally wants to play smooth, it just needs to be told when / how much to roll off. It gives up some low end to play better thru the midrange, but it still makes bass in the ported enclosure it's in.
In contrast, the SS 8545 has a CMS is 1.62 mm/N... it's more "floppy", which also means it plays lower; however, it cannot match the clarity of the M165NQ. It is plain as day, and I've heard it in a direct application comparison with the same Dynaudio Esotar tweeter. The only thing not the same are the caps on the woofer... Duelund CAST PP on 8545, Sonicap on the M165NQ. It would be shocking if
that accounted for the difference in clarity. I don't think so.
The Merlin VSM Danny did measures great, and sounds far better than the original version... this is a good example where a simple frequency response measurement may not tell the story of "clarity". That measurement is a 4ms snapshot in time, what happened after that time, and when did the speaker stop moving? The Decay Plot...
When you start looking at woofer drivers that have a similar CMS measurement to the M165NQ, get ready to spend some money. I certainly haven't heard but a fraction of drivers that are out there, but the M165NQ has to be one of the best values anywhere... and might be among the very best sounding too.
My Wilson Audio Duette use a ScanSpeak Revelator 22W/4851T00 8" Woofer. Those SS 4851 Revelator 8" are $381/ea (Wilson charges $800/ea, I inquired), with a CMS of 1.85mm/N; however, there is more clarity in the midrange from the Duette compared to the 8545 in the Merlin VSM. I suspect similar CMS measurements from drivers of different sizes don't equal the same story in clarity.
Having already owning the Duette, it would be interesting if the GR 8", if it ever happens, has top shelf clarity but because of the larger diameter can also play into the mid-30Hz range in a ported enclosure. For many, that is enough low end... and that would be quite a speaker - I bet.
Of course, I could be wrong about all of this, but that's what my eyes, ears, and connecting dots are telling me.
