My RS180 MTM Design

[hoxuanduc]

Re: My RS180 MTM Design

Mr. Bagby,

Many thanks for sharing the elegant cross over design. The speakers sound great! Spot on tonal balance, natural, great imaging and soundstaging. On one song a bird was singing 5ft above the speakers right at the ceiling. You can hear surround effect on 2 channels (e.g. sound coming from behind you w/o processing) on Netflix.

Duc

[Jeff B.]

Re: My RS180 MTM Design

Mr. Bagby,

Many thanks for sharing the elegant cross over design. The speakers sound great! Spot on tonal balance, natural, great imaging and soundstaging. On one song a bird was singing 5ft above the speakers right at the ceiling. You can hear surround effect on 2 channels (e.g. sound coming from behind you w/o processing) on Netflix.

Duc

Thank you for the kind comments. I am glad you are happy with them.
Jeff

[billschulte]

Re: My RS180 MTM Design

Jeff...any chance you could give me a crossover for the HDS Scan Speak tweeter as a substitute for the Dayton ...thanks

[Chris Roemer]

Re: My RS180 MTM Design

Link, or at least a full model no.?

[Jeff B.]

Re: My RS180 MTM Design

Jeff...any chance you could give me a crossover for the HDS Scan Speak tweeter as a substitute for the Dayton ...thanks

It wouldn't be real accurate. I have files already, but I don't have any RS180's to work with, so I can't measure them together. If I substitute the HDS files for the RS28a files there would be some assumptions that would have to be made regarding response on the same baffle and how the sensitivities actually match up. This would make the crossover less than exact.

[DannyG]

Re: My RS180 MTM Design

Jeff nice job and nice and simple x-over,I think I've seen some builds useing these same drivers but the x-overs were far more complicaded.Is there a reason for a more involed x-over?

[Jeff B.]

Re: My RS180 MTM Design

Jeff nice job and nice and simple x-over,I think I've seen some builds useing these same drivers but the x-overs were far more complicaded.Is there a reason for a more involed x-over?

I have found that there are usually simpler ways to achieve the target transfer function than I often see used. It's all a matter of optimization of the network.

[DannyG]

Re: My RS180 MTM Design

Right,I look for a good build but dont like to spend more money on the x-over than the drivers.

[RBG]

Re: My RS180 MTM Design

Jeff, are you planning to make some new designs using new RS paper drivers?

[Jeff B.]

Re: My RS180 MTM Design

Jeff, are you planning to make some new designs using new RS paper drivers?

Yes actually, the 180 and the RS28f are on the docket. Probably after the InDIYana gathering.

Jeff

[Jesse055]

Re: My RS180 MTM Design

I'm having some difficulty understanding how you came up with the inductor and capacitor values? I had made a crossover based on 4 ohm tweeter and woofer at 1700 from all the online calculators for LR 2nd orders and I came up with .75Mh and 11uf caps?

Now I do realize the tweeter is 3 rd order so I see that is most the difference ibut those numbers still off too. I'm just not understanding how a 1.2 mh inductor with a 20uf cap crosses at 1700 hz. Hope you can explain how these values were determined

[Jesse055]

Re: My RS180 MTM Design

I'm having some difficulty understanding how you came up with the inductor and capacitor values? I had made a crossover based on 4 ohm tweeter and woofer at 1700 from all the online calculators for LR 2nd orders and I came up with .75Mh and 11uf caps?

Now I do realize the tweeter is 3 rd order so I see that is most the difference ibut those numbers still off too. I'm just not understanding how a 1.2 mh inductor with a 20uf cap crosses at 1700 hz. Hope you can explain how these values were determined

[Ryan_M]

Re: My RS180 MTM Design

There is lots the online calculators don't account for...

- Baffle step compensation
- response of the drivers
- dynamic impedance of the drivers
- baffle diffraction effects
- difference in sensitivies between the drivers
- tonality of the speaker
- time alignment and phase
- presentation of the speaker
- off axis response and power response
- plus a few I'm probably forgetting

The crossover is where the magic is. This is what makes greats like Jeff, well great. The online calculators will give you typically nothing that will function well besides to protect the drivers.

[isaeagle4031]

Re: My RS180 MTM Design

Fairly simple, yet complex at the same time. The online calculators assume that the woofer and tweeter are static loads. However, impedance varies with frequency. Jeff uses an excel spreadsheet that he developed (and many of us use for that matter.)

[Jesse055]

Re: My RS180 MTM Design

I understand it's complex, but at the same time these values are based off linkowitz Riley work and those were pretty smart guys also. Also the. Ross over was still stated as 1700 hz. But still, I talking strictly cossover point and these values correspond to a point around 900 hz. So, I would just like to have someone hopefully jeff explain it so I can understand......or maybe he is low passing at 900 hz?