Mid-Drivers and Crossovers, Point me in a Direction?...

[wcriley]

Greenboy did one, too, made out of a rack case.
Might still be photos and details somewhere in the old fEARful threads.

[will33]

Originally Posted by Bmorefoozler

The CBG 1212/6 xovwer is 4 ohms/8ohms and available pre-built at speakerhardware.com
throw that and an 18sound mid in a seperate box and you are good to go.

The problem I wouod have there, aside from being driver-specific to the fearful, is that, I think anyway, the CBG crossover is 12db/oct. around 750hz. Fs of the closedback mid is up around 500hz. Not steep enoigh being that close to fs I would think. Any closedback mid I've heard doesn't have a "pleasant" sort of distortion, but a rather nasty one.

OP. A call to Leland Crooks might be in order. Explain what you want to do and he could point you in the right direction. Either by just building the thing or by other advice.

A separate topbox isn't a bad idea at all. Could make this thing sort of an add-on to other future cabs. The lowpass section will vary, 4 or 8ohm nominal impedance there but more so, various different woofers impedance curves rising at different rates on the way north.

[will33]

Or...if you really wanted to break some rules.....could just put a 1.6khz highpass only filter on the 6 and chain it along with whatever you've got. Most woofers impedance should be rising enough by then, it might not cause a problem for a 4ohm amp.

Most decent bass guitar speakers will also have good output up there, probably conflict with the 6 too much, and might sound worse than just letting them run on their own. That's what happens when you break too many rules.

[wcriley]

I think that at least some of the CBG x-overs are asymetrical. Different slopes and -3 points on the HP and LP sections.

But Will's right about them being driver specific and the general X-over area (somewhere in the 700-800 range).

[Passinwind]

Originally Posted by Freddels

IIRC, 4Mal or Passinwind did a separate box for a mid driver. Do a search and then contact them.

I've done a few different ones, pics and some very basic details are here.

[Count Bassie]

Originally Posted by Freddels

IIRC, 4Mal or Passinwind did a separate box for a mid driver. Do a search and then contact them.

I'll do that. I know there's also that fEARful Headcase jig.

[Count Bassie]

Eh, apparently I missed a few posts here! Reading...

[Count Bassie]

Originally Posted by will33

Or...if you really wanted to break some rules.....could just put a 1.6khz highpass only filter on the 6 and chain it along with whatever you've got. Most woofers impedance should be rising enough by then, it might not cause a problem for a 4ohm amp.

See, this is 'dark arts' in my book...

Originally Posted by will33

Most decent bass guitar speakers will also have good output up there, probably conflict with the 6 too much, and might sound worse than just letting them run on their own. That's what happens when you break too many rules.

The Hartke VX 215 has 15s that are called by some number followed by "LF". It's a dark-sounding box without the tweeter, and I'm thinking now that a mid with a high low-pass shut-off would give it some 'body' in the upper mids.

[Count Bassie]

The box for housing a mid-driver, a-la 'Headcase', I think...

[will33]

Plenty 'nuff room in there. I have an SM400s like that. I'd start by putting the 6 in a box and using your amp to actively biamp to it. Can toy with different crossover frequencies, try different 6's etc. until you run into a configuration you really like, then have somebody design a passive crossover for your setup. Active biamp capability like that eliminates the need for a passive XO in the first place.

I do it all the time, with that amp, or an 800rb, or my Tmax, or anything with an active crossover.

[Passinwind]

Originally Posted by will33

Plenty 'nuff room in there. I have an SM400s like that. I'd start by putting the 6 in a box and using your amp to actively biamp to it. Can toy with different crossover frequencies, try different 6's etc. until you run into a configuration you really like, then have somebody design a passive crossover for your setup. Active biamp capability like that eliminates the need for a passive XO in the first place.

Yep, that's how I do all of mine. My active crossover appliance also lets me do time alignment and dedicated EQ per driver, both of which can be ported to a passive crossover if you're sufficiently masochistic.

[will33]

Originally Posted by Passinwind

Yep, that's how I do all of mine. My active crossover appliance also lets me do time alignment and dedicated EQ per driver, both of which can be ported to a passive crossover if you're sufficiently masochistic.

Hahaha....


If I pull the XO from my PA rack, I can pile different eq, etc. on each side, still no time alignment majic though. It spins my head enough just trying to figure out how to make a passive do what my active does. Perhaps I should delve into this masochism.

[Count Bassie]

Originally Posted by Passinwind

Yep, that's how I do all of mine. My active crossover appliance also lets me do time alignment and dedicated EQ per driver, both of which can be ported to a passive crossover if you're sufficiently masochistic.

See? Dark arts! Charlie, Will, I simply cannot go there. But I can do the x-over on the SM-400 easily enough, find the weest-spot with a reasonable driver, and then do the passive filtering.

Would a high-pass filter for the mid alone be enough, without the actual crossover? Maybe I should just let the 15s fly and slide the mid driver in where it would be effective reinforcement for the upper mids?

Originally Posted by will33

Hahaha....


If I pull the XO from my PA rack, I can pile different eq, etc. on each side, still no time alignment majic though. It spins my head enough just trying to figure out how to make a passive do what my active does. Perhaps I should delve into this masochism.

Dude... God bless you...

[Passinwind]

Originally Posted by Count Bassie

See? Dark arts! Charlie, Will, I simply cannot go there. But I can do the x-over on the SM-400 easily enough, find the weest-spot with a reasonable driver, and then do the passive filtering.

Would a high-pass filter for the mid alone be enough, without the actual crossover? Maybe I should just let the 15s fly and slide the mid driver in where it would be effective reinforcement for the upper mids?

After you try biamping first and see what the highest frequency is that works reasonably for you, that answer should come more into focus. If you can con someone into doing an impedance sweep on your 15s it'd help a bit. There's certainly plenty of tech talent in your part of the world.

In some of my cabs I've used a simple 1st order low pass on the woofer, which simplifies things a bunch. Still kind of expensive for a 2-15 though.

[Foz]

...on the cheap maybe slap together a 3 liter box and buy a $40 emi alpha 6

http://greenboy.us/fEARful/DL/12+6/

http://www.speakerhardware.com/alpha-6a.php