True 3-way fEARful bass enclosures

[edwinhurwitz]

The thing I love about the fEARful designs is the mid. For me, I prefer a paper cone mid driver, crossing in the 800~1000 range. I play Rics, and that type of design makes my bass's grind the way they were supposed to instead of a compression driver horn crossed at 4kHz. But I also like a woofer that can play up to 4k w/o a mid/tweet when I do old school. The fEARful LF driver just can't go that high. Everything is a compromise. I really luv my fEARful 15/6 with the stock CBG x-over most of the time. I have a Genz-Benz 410 Uber for the other times.

I did a show at the Fillmore in Denver where I used a 15/6/1 in conjunction with a Sunn 200S with JBL K140s. QSC CX1202v driving them with 800 watts for each cabinet. It sounded great. The fEARful did all the nice deep lows and highs and the JBLs provided that perfect midrange.

 

[DiabolusInMusic]

I can safely say that this mod has now been done to a 1212/6 if anybody is thinking about trying it. I got this mod done a few weeks back and it is a major improvement (to my ears) over the CBG, highly recommended.

Big thanks to @12bass for helping me out with assembly and install.

 

[Jim Carr]

Hi All—

Just resurrecting this zombie to ask: Has anyone has built a true 3-way crossover for a 12/12/6/1 fEARful yet? A good friend is building a 1212/6/1 and wants to go t3w, a.k.a. true three way, a.k.a. true 3-way. Have searched on Greenboy forums and found the
current 2015 designs, but no 12/12/6/1 circuit other than some verbal guidance.

We have that (latest?) paper from 2015 on the 15/6/1 t3w, but wonder if anyone has executed the posited, but unrealized 1212/6/1 version. Thanks!

 

[Foz]

PM sclift for advice - he and I discussed this question some time ago and IIRC he had some pretty well formed ideas on how to mod the 12/6+1 tru3-way for that application.

Good Luck

 

[12bass]

Just resurrecting this zombie to ask: Has anyone has built a true 3-way crossover for a 12/12/6/1 fEARful yet? A good friend is building a 1212/6/1 and wants to go t3w, a.k.a. true three way, a.k.a. true 3-way. Have searched on Greenboy forums and found the
current 2015 designs, but no 12/12/6/1 circuit other than some verbal guidance.

We have that (latest?) paper from 2015 on the 15/6/1 t3w, but wonder if anyone has executed the posited, but unrealized 1212/6/1 version. Thanks!

Built a T3W 1212/6/1 crossover for DiabolusInMusic back in 2015, based on the T3W 15/6/1 IIRC. However, it would be best to contact sclift and confirm the design specifics. From what I recall, it sounded very good, though slightly different than my T3W 15/6/1.

 

[Foz]

Basically IIRC it amounts to halving the coil values and doubling the caps on the dual woofs - using the 6nd410 mid with the values shown for the 12/6 but with no resistor pad - and using the ASD1001S or D220Ti-8 tweet driver then turning the L-pad all the way up [or leaving it out]. But get sclift to weigh in if he is available.

Something like this?

 

[12bass]

Can't seem to find the schematic I used (or the relevant correspondence with sclift), but from the pic posted above it looks like we used the XD125 tweeter.

 

[Foz]

I believe the XD125 will work - again it probably needs to be dimed to balance. I am a little concerned about the phase match up with the mid going to dual woofs [wofferage impedance change] = might have to modify the mid board / maybe flip the polarity? Perhaps Steve [sclift] has the validated 12/6 electrical model handy and would be willing to pop 2 woofs in it and take a looksee at the summing behavior of the woof + mid.

If not I can try and dig it up but I would try very hard to get Steve's input before buying parts et cetera.

Good Luck

 

[Jim Carr]

Thanks guys. Trying to get my friend Bill Cornish to join in here.

 

[DiabolusInMusic]

While I own the cab, I owe a great debt to @12bass for helping me out with everything. This is all over my paygrade. I can gladly pop the cab open if anybody needs but that is a much better picture of the board above than I could take.

It has been a long while since we did it but the upgrade gave everything a much more even feel, the highs felt a lot less shrill. I am still 100% satisfied with the cabinet.

 

[12bass]

While I own the cab, I owe a great debt to @12bass for helping me out with everything. This is all over my paygrade. I can gladly pop the cab open if anybody needs but that is a much better picture of the board above than I could take.

It has been a long while since we did it but the upgrade gave everything a much more even feel, the highs felt a lot less shrill. I am still 100% satisfied with the cabinet.

Glad you're still satisfied with it. IMO, the T3W is a huge improvement over the CBG... much smoother sounding, especially above 2kHz or so, without that nasty ~4kHz midrange driver cone resonance peak. Gives the design much more of a flat, balanced, "what goes in is what comes out" sort of sound. A friend and I built our fEARfuls at the same time, and his 15/6 has the original CBG crossover; the difference is impossible to ignore, as the ~4kHz harshness is immediately evident. Personally, I wouldn't even bother with the original crossover, and would just "do it right" with the T3W.

 

[Jim Carr]

While I own the cab, I owe a great debt to @12bass for helping me out with everything. This is all over my paygrade. I can gladly pop the cab open if anybody needs but that is a much better picture of the board above than I could take.

It has been a long while since we did it but the upgrade gave everything a much more even feel, the highs felt a lot less shrill. I am still 100% satisfied with the cabinet.

Do you have a drawing or schematic or even a photo of a t3w crossover for a 1212/6/1?

 

[DiabolusInMusic]

Do you have a drawing or schematic or even a photo of a t3w crossover for a 1212/6/1?

The picture in post #85 is the board. I'll try to pop the cabinet open later today and snap some pictures for you.

 

[JimVS]

Is there a link for Greenboy registration?

 

[12bass]

I've contacted Steve Clift regarding the T3W 1212/6/1.

Is there a link for Greenboy registration?

Should be available here: [Invalid or Expired Link Removed]

 

[12bass]

Do you have a drawing or schematic or even a photo of a t3w crossover for a 1212/6/1?

1212/6/1 info from the T3W PDF, page 3:

No design has yet been formulated or tested for the 1212/6. If one wishes to attempt this we suggest using the standard woofer low pass for that module (1.5mH inductor + 68μF capacitor into the dual 3012LFs), the 15/6 midrange network described below, and one of the tweeter modules that is suitable for the 15/6/1 + 15sub. The midrange pad and level switch could be retained to provide two voicing options, or simply removed.

This seems familiar... what we went with in the above T3W 1212/6/1 was reusing the existing CBG woofer lowpass circuit for the 1212/6, plus the T3W 15/6/1 midrange bandpass and 15/6/1 XD125 highpass circuits for the midrange and tweeter (6/1). So, from this it seems that a different tweeter could also be used, as long as it has sufficient output to match the midrange/woofers. The T3W crossover board pictured above is a composite circuit with both the 15/6/1 midrange bandpass and XD125 highpass filters (woofer lowpass is on a separate board).

 

[Jim Carr]

Thanks much!

 

[Foz]

FWIW I'd probably use a bigger coil [1.65 mH target] - the ESQ55-16-1600 would fit the bill pretty close:

Link Removed

 

[sclift]

The posts by Foz and 12bass outline the approach. The T3W mid networks optimize the driver response on the baffle. The 1212/6/1 baffle layout around the mid and horn is roughly the same as the 15/6/1 layout, so it would be slightly preferable to use the mid network for the 15/6 instead of the one for the 12/6. Remove R1, R2 and the switch for a flat response, or leave them in if you want to try throttling the mids back a touch. An XD125 or an H07E/D220Ti would work for the high end. The XD125 has the advantage of a simpler crossover.

 

[Foz]

Howdy Steve - What coil would you use of the woofs?