Single driver vs traditional 3 way loudspeakers

Not sure where to get this EQ you are talking about.. Ebay??
Price?
The WBer experiements set me back, audio budget very tight.
So what is your purpose of testing EQ in your lab. 
To ck to see where a  speaker is weak?
I am not sure what the reason is testing EQ?
I am sure if I hook the W8 or W4 or even my complete 4 way speaker to some EQ gadget, like having say 10 EQ levers,, I am sure the sound,,or lets say, some fq ranges that I perfer might geta boost in some recordings. 
But then the  musc has to pass through this gadget = more distortion. 
EQ gadget may boost FQ's, but adds distortion. 
The EQ thing on the Onkyo sounded better in off mode. 

Not sure why you don't play around with the davidLouis VX6 and add in a  TB W3. 
Then add   a pair of DavidLouis Magnesium 8's per cabinet and then add in the Davidlouis Be/Nd tweeter.
25cm , not the 28.

I think you''ll be pleasantly surprised. 
That combo will beat my system, perhaps, ,,
magnet system is a  beast.
IMHO Magnesium is the best cone material to intergrate intoa  WBer system, as its neutral /not warm.  vs paper types which i don't like. 
I know you offer paper 10's, not my cup of tea. Too muddy/boomy. 

https://www.ebay.com/itm/324521174123?hash=item4b8ef8246b:g:BFIAAOSwoRRg1EKi

Price ?  Free, Online downloaded, sorry  i did not remember, which one

You are quite right Eric.
Tannoy makes coaxial speakers.
Coaxial speakers provide the magic that those with full range drivers are looking for.
Maybe that should be rephrased. What I assume those with full range drivers are looking for.
Tannoy and Altec got it right decades ago.
Point source is where it's at.

Tannoy dual concentric driver...I love mine....

Everyone's talking cones.
By far the best approach to a full range single driver speaker is electrostatic.
True, none is flat below 50Hz but there isn't the distortion produced by a full range cone at that frequency.