Previous postings from this thread can be found in the thread "K 145".

The last posting from "K 145", is duplicated here though.
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First of all I would like to wish everyone a HAPPY NEW YEAR, although the new year celebrations have been very somber here, since estimates say that more than 150 000 people have died in Asia, of which more than 3000 were Swedes.
None the less I have been occupied trying to learn some about my project.
I'm anxiously awaiting the return of Earl K and hoping the discussion will continue soon.

-Earl K
In case you're back already, there have emerged a few questions during the holidays, which I would be grateful if you would like to address first.

You wrote:
While Operating in 43XX mode :
- This concept of some form of overlap within the 4-way crossovers' slopes ( between bass and mids ) is something I believe you can do with your Behringer. This will help provide some sonic "glue" for the split between the 2215 and the 2123 . You'll need to experiment some to find the best combination .
For example ; the 2215h lowpass could be set for around 340 hz, while the 2123H hipass might be set around for 120hz ( you will need to port/tune) the 2123 to add a bit of midbass extension. I'd mix and match slopes , like 12db for the 2215 lowpass and 6db for the 2123 hipass .
I’ve been thinking, perhaps I should try to make the boxes sealed. I’ve read that sealed boxes have a much better transient response, so I was thinking of using a large (D, 30cm*L, 15cm) cardboard duct, for the 2123’s. For the bass-bin I was thinking of making it possible to go both sealed (80L) and vented (163L), by plugging the holes in the internal bracing.

Do you think a bit of shelving EQ, on both woofers would be able to extend the frequency range somewhat, as well as making it possible to lower the output, so that they won’t be as pronounced in the 300 - 600Hz region, like you said and at the same time keep the sonic “glue” intact?
Any comments on this?

I have also read somewhere that a first order x-over on the bass and mid-bass (giving a 90 degree phase shift), should be complemented by an equally first order x-over, or a third order (90 or 270 degree phase shift) x-over on the midrange, giving a total of 180 or 360 degree, or a full turn, phase alignment, which would give a perfect summation.
In my case, using the 2441, I think a third order x-over would be better/safer with a x-over at 1000Hz. Wouldn't you agree?
Then the task of time-aligning the drivers, would be much easier for the Behringer UltraDrive, at least I think.

While you were away for the holiday’s, I’ve also been busy trying to figure out the best/ideal x-over point between the 2441 and the 2123 and all things considered I think that 1000Hz/34cm distance between driver-center, seems best in my view.

I’ve also come across a program called XDir, which is said to calculate lobing-effects, though I’m not sure how it works, or how to find the best values. Perhaps you’re familiar with the program? http://www.tolvan.com/xdir/ .

BR
Roland
This is the latest design attempt of my MTM project and there are also a few pictures of the first pieces and a few of my tools.







EDIT: Here are a few of my tools, as well as one of my "co-workers", as always taking a brake!