crossover for RS180/RS28 MTM

[2ROCKY]

Hi guys I'm new to this. I built the BR-1 but I'm not shure if that counts or not. Anyway I plan to build a set of RS180/RS28 MTMs. Roman Bedark has designed a 2.5 for this MTM. I like the reason he designed this version but I can't find much information about how well it works. I figure that I'll bulid this version or the Natalie P. Any information or opinions you knowledgeable folks can share will be most appreciated.

Thanks Daniel

[ThomasW]

Hi, and welcome to HT-Guide.

It's Roman Bednarek

http://www.rjbaudio.com/RS180MTM/rs180-rs28-mtm.html

This might help you understand.....or just further confuse...:wink:

The design of a standard MTM 2-way is such that the two woofers acoustically couple to function as one larger driver across their entire passband.

Standard 2.5 ways (TMM) are constructed so there are some shared frequencies, but the bottom driver doesn't play as high as the top woofer.

If one makes a MTM as a 2.5 way, the woofers of course aren't reproducing the same frequencies throughout their passband. So at some frequencies the woofer are coupling and at others they aren't. I'd be curious to see the lobing pattern that creates....

So the concept of an MTM 2.5way sounds a bit weird to me given what I know about TMM 2.5 ways and MTM 2-ways. But I've never heard one of Roman's designs so I don't know how they work in the real world.

If Roman showed testing of the dispersion patterns comparing the 2-way MTM vs the 2.5 way MTM then making an educated guess would be easier. As is I don't have a clue.

My recommendation for you is build the NatalieP. Many have done so and all seem quite pleased with what they built.

[Rudy Jakubin]

I've been comparing the Natalie P's and Roman's 2.5 for the past two weeks.
In Roman's design I've put the .5 as the top woofer and this setup sounds more like a TM instead of an MTM. The Natalie P's are wonderful crossover's for an MTM.
So far I'm liking Roman's 2.5 only because I stand up and move around a lot. Sitting down I can't tell the difference.
Now if only Jon Marsh would come up with a Quasi-Series crossover for the RS180's and the Seas 27TDFC tweeter.
Either way you can't go wrong. This is an excellent sounding speaker design.

[2ROCKY]

Thanks

First, Roman please let me apologize for spelling your name wrong.

Thanks guys, your replies really help me to understand a little more, I think. Rudy is there much of a price difference between the two crossovers?
That might be a large determining factor for me. Roman sent me a layout for the 2.5. Rudy do you have or canyou direct me to a layout for the Natalie P cross?
The more I look at doing this, the more I know that I don’t know.
One thing I do know is I couldn’t do this without help from folks like you.
Thanks a lot.
This is going to be fun!

Thanks again.
Daniel C

PS Thomas do you live in Denver by any chance?

[ThomasW]

Images not available

PS Thomas do you live in Denver by any chance?

Yep... :B

[2ROCKY]

Thomas, thanks for the pictures. What am I looking at? Are they two different crossovers or sections of the same one? Do you use
silicone to hold the caps and resistors too? I been wondering about
the thickness of the wire used for speakers. People use large gauge
wire to hook up their speakers but the wire that the caps and resistors have is more like 20 or 22 gauge. I know that I don’t know what I’m talking about but why hook up large gauge wire to very small gauge wire? I wouldn’t hook up a fire hose to a garden hose.
Anyway thanks again.

Daniel Cross

Oh by the way I live in Longmont