Hi chaps just to fill you in on my thoughts so far.
I have posted some photos of the RTA pink noise plots with and without eq here as well as my first test results:-
http://myweb.tiscali.co.uk/prosoundhire/dr290.htmI am keeping a very subjective point of view regarding this cab even after spending the time building it. In fact to be fair this gives me all the more reason to be sure it does what I want of it before commiting to spending more time building the next cab.
Its very time consuming and you have to be very accurate as all of the cab is built with curved panels and an overall 4deg slope top and btm. You have to bear in mind these things are a very complex design/build next to any other cab design.
As far as testing the cab:-
It was simply superb on the vocal output.
My Current tops sounded better with
some cd source material but the DR's sounded better with other's. Still room for further EQ improvement on the DR290.
After setting the system flat, and then tweaking a little more down on the top end, the Vocal check with a mic was the last thing I did.
Next to the DR290 my current tops sounded pretty thin in the lower mids.
It was simply superb on the vocal output.
The output of the DR290 was higher than my existing tops at high levels.
I dont have a laptop to use Smaart, so can't carry out any tests other than the RTA measurement and time delay/phase settings using my Ultradrive (I understand the Behringer measurement mic is not accurate for phase response but good for flat eq response)
I plan on building another cab design before I commit to the time building another DR290.
I have plans for a coaxial 1x12 & 2". I am going to mock up the horn and again do a full A/B/C listening test to try and get a subjective result between all three top packs.
One thing I need to check out is the horn impedence again as I was pretty sure they where both 16ohm units, simply because next to the 2416 was a 16 in a circle. But if they are both actually 8ohm units then I was pushing way to much into the HF component which would explain the high un eq'd RTA level of the DR290 as seen on the RTA plot.
Not sure about the polarity issue though as the Ultradrive swapped both the 12" and the pair of 1" drivers around. Its more than likely that I have a cocked up the polarity of one of the patch cables I made to test the system out on this last test as the polarity was not swapped when I first tested the cab.
Dont quite understand why one poster thinks that I am trying to rubbish Bills designs, Dont think I would have committed to the long and complex build if that was the case.
Dave