Need help with simple MTM crossover design, how does this look?

[DaveFred]

Does this MTM crossover look like it will work?

I am looking to build an MTM with Dayton RS180-4 bass drivers and DC28F tweeters.

Using all I learned yesterday, I came up with this crossover design,

This is what the freq response looks like,

and possibly using these components,

Am I even close on this?

Thank you,

David.

 

[Lojzek]

Hi Dave, you have simulated without a baffle step impact. The overall sensitivity with full bsc compensation and worked out crossover will be about 85 dB. I'd increase the XO frequency to 2 kHz. The graph is my simulation of the units with your crossover in an enclosure and free space. Used the tweeter response off Zaph's website. The closer to the walls, the less of bsc should be calculated in. One has got to try out first to know better.

 

[DaveFred]

Hi Dave, you have simulated without a baffle step impact. The overall sensitivity with full bsc compensation and worked out crossover will be about 85 dB. I'd increase the XO frequency to 2 kHz. The graph is my simulation of the units with your crossover in an enclosure and free space. Used the tweeter response off Zaph's website. The closer to the walls, the less of bsc should be calculated in. One has got to try out first to know better.

Bok,

Did you model one or two bass drivers?

David.

 

[Lojzek]

I have modeled two of the woofers wired in series as you have done. The spl reduction comes from the baffle of the enclosure that is not supporting bass frequencies as an "infinite baffle" is, and manufacturer's graphs are done in such a way. Still, if you move your loudspeakers closer to the walls then this range of bass spl will start to increase, that's why I said that one needed to experiment with it to develop a feeling what one might like better.

 

[DaveFred]

How about this one,

This is still with the RS180-4's, but I swapped out the Dayton Tweet for an Usher 9950-20.

R4 can be easily changed to raise and lower the output above 1K hz.

What do you think?

 

[Lojzek]

If you have Excel, get Response Modeler, define your baffle measures there and work out new frd's to see what kind of an effect it would made your new filter.

 

[Lojzek]

Noticed your latest 4th order crossover filter with RC's on both of the units with parallel RL before everything. That all seems unnecessary complicated for you could have gotten an equivalent response with almost only half as much parts. I can promise you to work out frd's and zma's for your woofers once you define the baffle measures and driver position. Then you will see more clearly what the crossover is doing.

 

[armeker]

It looks like you are showing a 6db gain on the woofers like they are wired in parallel but your diagram shows series. I think you might have something off.

 

[DaveFred]

This is the crossover I am going with.

I changed the drivers as the project was getting to expensive to build. I am building these for fun more than anything just to see how they turn out.

I ordered everything today and will post pictures of the build if anyone is interested.

Thank you,

David.