Mtm crossover question

squamishdroc

I posted my latest build on my IG account the other day and some guy asked me if i used a D'Appolito crossover. I just used a 12db slope on both drivers. He then tells me it is not a D'Appolito design then and i should change the crossover. Is there a certain way to design a crossover for an mtm or is the way I did it just fine? 

PWRRYD

I think Joe D'Appolito started out with 3rd order Butterworth acoustic slopes on his MTM.  Later he decided that 4th order Linkwitz-Riley worked better.  I've done 3 MTM designs myself and have always targeted 4th order L-R slopes, with minor voicing tweeks.  They all sounded very good to my ears and measured well.

PWRRYD

BTW those look great!  How do they sound?

rjj45

I agree with PWRRYD - the guy was blowing smoke at ya - I"ve typically used the same topology as a normal TM - 2 order LR on the woofer, 3rd order BW on the tweeter. They measured and sounded great.

S7910

PWRRYD said:

I think Joe D'Appolito started out with 3rd order Butterworth acoustic slopes on his MTM.  Later he decided that 4th order Linkwitz-Riley worked better.  I've done 3 MTM designs myself and have always targeted 4th order L-R slopes, with minor voicing tweeks.  They all sounded very good to my ears and measured well.

I fully agree with this for the traditional "D'Appolito style" MTM.

However, as to the OP's question, I would say that the crossover that achieves the desired response from the drivers used is the correct one for an MTM. From what I've read all D'Appolitos are MTMs, but not all MTMs are D'Appolitos - if that makes any sense.

squamishdroc

Thanks guys - kind of how I felt too. They do sound good for the cost of the drivers - good bass for a little driver.