Is there an xover design program..

[cobbpa]

..that lets me input the components of an already made crossover design and modify it? Specifically, I'd like to alter some of the Mission Possible designs to have no BSC built in. I don't have testing software but have started playing with some of the FRD tools. Is this possible or is it better to start from scratch?

[cjd]

It is best to approach the designer(s) and request a "no BSC" version

You need to start with good measurements - once you have those, all crossover software will help you do what you need to do. But, most the designs here don't make every component discrete, so BSC is built into the crossover.

C

[Jed]

.. to have no BSC built in.

Yeah this is possible if you get the FRD and ZMA files from the designer. However, I can't imagine this type of speaker sounding very good- even when placed against a wall. Which speaker did you have in mind and what are your reasons for no BSC? Just so we're all on the same page.
Jed

[ThomasW]

FWIW I can tell you that there are no FRD or ZMA files available for Jon's designs.

And since the BSC is integrated into Jon's designs, one would need to completely redesign the crossover from scratch to obtain a BSC free design.

There is a remote possibility that Jon will have a few vacation days in Denver sometime in mid October. If that's the case, and if the 'gods' smile, there maybe some BSC free designs available. BUT don't hold your breath since all this is tentative....

This version of the original M8a-MKIII has modified BSC for on-wall mounting...

http://home.comcast.net/~audio-worx/page92M8a-MKIII-Sealed.html

The box can be sealed, ported, or the internal volume changed to increase the bass output. BUT do not change the baffle width or the driver spacing.

Short thread about the various M8a projects

http://www.htguide.com/forum/showthread.php4?p=66268#post66268

Pic of the original design HiVi M8a woofer, Focal TC120DX tweeter.

[cobbpa]

I've been making some posts & searching to do some research on similar subjects. My uncle is building a HT room and wants to put some speakers on the wall; not sure yet if the enclosures will be outside the wall or hidden behind drywall. I've suggest to him the Dayton RS towers as mains & RS WMTW center along with the Modula MT as surrounds. I've given him a design where the towers & center may be able to be placed a foot or so in front of a rear wall, but that's yet to be decided.

[cjd]

Well, I'll be needing a "near wall" set for my own HT, 'cause the room is just too small for anything else.

That's not entirely in the near future on the project list, though the sooner I get my other stuff done the sooner I get to play again...

I have appropriate variations on the MTM's as well (minimal/no BSC)

C

[cobbpa]

Well, I'll be needing a "near wall" set for my own HT, 'cause the room is just too small for anything else.

That's not entirely in the near future on the project list, though the sooner I get my other stuff done the sooner I get to play again...

I have appropriate variations on the MTM's as well (minimal/no BSC)

C

Yeah, I've shown him your design also, the only concern is the size of the room. It's something like 9'x 20 x 35 with half of one long side open. That's just an estimate, but it's something around that size. Hence choosing speakers big on cone area. We may use your MTM's as surrounds.

[cjd]

Just puttin the options out there

You could always cross actively to a "bass" bin - maybe some 10" RS subs...

Or we could consider pushing my next project a bit ahead...

C

[Outfitter]

Or we could consider pushing my next project a bit ahead...

C

C'mon CJD, what kind of incentive do you need to get started? As much as i like the big WMTW with the 225, it's just too big for me. I'd like to know what it's gonna take to push you to get the HT project started!

[cobbpa]

Just puttin the options out there

You could always cross actively to a "bass" bin - maybe some 10" RS subs...

Or we could consider pushing my next project a bit ahead...

C

If it's close to the cone area of the big RS towers, but designed for near-wall placement...I would give serious consideration to building some.

[cjd]

C'mon CJD, what kind of incentive do you need to get started? As much as i like the big WMTW with the 225, it's just too big for me. I'd like to know what it's gonna take to push you to get the HT project started!

Well, it may not be much help for you then. But, it may. I'm somewhere between a pair of RS180's and a pair of RS225's for bass duty. It'll probably be a 2 box affair as well, so I suppose I could option both... :P

Really, I have a couple furniture projects to do. Have to finish my desk (drawers outstanding), owe my wife a box (smallish) and a narrow dresserish thing. And for the latter, I may need a bandsaw to do the legs.

I also have a trip to Italy I'm still paying for (~2 weeks)... so, there's no "play" fund available.

Anyone that lives close enough or otherwise wants to loan boxes/drivers, I can probably get a jump start if I'm not doing the box construction labor.

C

[cobbpa]

Well, it may not be much help for you then. But, it may. I'm somewhere between a pair of RS180's and a pair of RS225's for bass duty. It'll probably be a 2 box affair as well, so I suppose I could option both... :P

Anyone that lives close enough or otherwise wants to loan boxes/drivers, I can probably get a jump start if I'm not doing the box construction labor.

C

RS225's = teh sweetness.

Where abouts are you located?

[Jed]

Another quick option would be to download Roman B.'s Daedalus speakerworksop file from his website (rjbaudio.com) and modify the crossover using his measurments. This speaker uses RS225, RS125 and RS28a.- Jed

[cjd]

RS125 is a no go for me, and the sensitivity of his isn't either.

I'm in NE IL...

let's see how thing look, I'll ponder this some.

C

[Jed]

RS125 is a no go for me, and the sensitivity of his isn't either.

Well, remember this design wouldn't have the BSC, so add 3-4DBs and we're at 87-88DBs. Not bad at all.

[cobbpa]

RS125 is a no go for me, and the sensitivity of his isn't either.

I'm in NE IL...

let's see how thing look, I'll ponder this some.

C

Hmmm...I do get up to Chicago several times a year, and a cousin also involved in the project does live in Wheaton & enjoys woodworking..

If somehow your free time & the window between which my uncle decides to build & when he wants them done by line up, it'll be kind of amazing, but very optimal. Keep us posted!

[Doug Lockwood]

Small World. I live in Wheaton Ill. too.

[mmoeller]

I work in Lisle...

[Rick Craig]

I've been making some posts & searching to do some research on similar subjects. My uncle is building a HT room and wants to put some speakers on the wall; not sure yet if the enclosures will be outside the wall or hidden behind drywall. I've suggest to him the Dayton RS towers as mains & RS WMTW center along with the Modula MT as surrounds. I've given him a design where the towers & center may be able to be placed a foot or so in front of a rear wall, but that's yet to be decided.

I have a version of the WWMT that allows you to vary the BSC. Ask Dennis Murphy to do a crossover for you with the woofers in series and he can minimize the BSC for you.