K140 2 way bass guitar cab?

[jnewmark]

I'm planning on having a 2 way bass guitar cab built for me with a K140 and a as yet to be determined horn/tweeter. I did a little searching here and discovered that the K140 should be in a 4 cubic foot box tuned to 38 hz. Would the addition of a horn/tweeter change this inner volume? Also, should the cab be tuned differently, and where should the crossover point be? I'll be using using between 300- 500 watts in this cab. Any other advice you care to give would be greatly appreciated, as I will be turning over this info to my builder. I would like to go as light as possible as far as building materials go. Thanks.

[jcrobso]

The volume of the horn will affect the cabinet if the horn is a large one.
In general the K140 is fairly good up to 3khz. The JBL spec is 2.5khz.
I would run the K140 with out a crossover, add the HF driver with 12db( or higher) at about 2~2.5 KHz.
Since I have a pair of K140s in an old Acoustic dual 15" bass bottom, what would I use? JBL or other brand? So my question to you is what is you budget for the HF driver? JBL could be some BIG $$$, there are some other lower cost solutions. Think about what you want to do and re-post.
Plywood would be the lightest. John

[jnewmark]

The volume of the horn will affect the cabinet if the horn is a large one.
In general the K140 is fairly good up to 3khz. The JBL spec is 2.5khz.
I would run the K140 with out a crossover, add the HF driver with 12db( or higher) at about 2~2.5 KHz.
Since I have a pair of K140s in an old Acoustic dual 15" bass bottom, what would I use? JBL or other brand? So my question to you is what is you budget for the HF driver? JBL could be some BIG $$$, there are some other lower cost solutions. Think about what you want to do and re-post.
Plywood would be the lightest. John

I will be running this cab full range, so would'nt I need a passive crossover in the cab? In another bass combo I have an E140 paired with a 100 watt Foster tweeter that I really like the sound of. I aslo have a Selenium horn in another cab, but I much prefer the Foster.

[jcrobso]

There is not a big sound difference of a K140 vs E140.
The biggest difference is the weight of the magnet! I have an E140 also.
What works with the E140 should also work with the K140.

[jnewmark]

There is not a big sound difference of a K140 vs E140.
The biggest difference is the weight of the magnet! I have an E140 also.
What works with the E140 should also work with the K140.

Thanks. And a passive crossover ?

[Harvey Gerst]

Thanks. And a passive crossover ?

Just a roll-off for the high frequency unit; let the K140 run wide open.

[Fred Sanford]

I have a similar sort of setup in two cabinets, one with 1 x 15 (E140) & 2 x 10s, one with 2 x 15s (Altecs). After trying lots of permutations, both ended up with the "bottom" 15 running full range, and the "top" 15 or 10s high-passed & level-controlled.

je

[jnewmark]

Just a roll-off for the high frequency unit; let the K140 run wide open.

Let's see if I understand this right ( I'm not much of a tech guy ). I need to tell my cab builder that I want the K140 to run wide open and just a roll-off for the tweeter? Also, 4 cubic foot cab at the minimum?

[jcrobso]

Let's see if I understand this right ( I'm not much of a tech guy ). I need to tell my cab builder that I want the K140 to run wide open and just a roll-off for the tweeter? Also, 4 cubic foot cab at the minimum?

The guy that's building the cabinet, is he a speaker guy or just a box builder?
Is he just building just the box or the whole speaker system? I understand that your not a tech guy, but a little more info would be very helpful.
I'm familiar with Selenium but not Foster.
What passive crossover are you using in the other cabinet? I think you have the info you just need to look at what you currently have.

[jnewmark]

The guy that's building the cabinet, is he a speaker guy or just a box builder?
Is he just building just the box or the whole speaker system? I understand that your not a tech guy, but a little more info would be very helpful.
I'm familiar with Selenium but not Foster.
What passive crossover are you using in the other cabinet? I think you have the info you just need to look at what you currently have.

The guy who will build it is Don Oatman at Low Down Sound in Detroit. He pretty much builds bass guitar cabs and is very knowledgeable when it comes to bass cabs. I was just hoping to give him enough info to get started, although I'm sure he will have his own suggestions. The other cab he built for me is a 2-way, 112, horn cab with an Eminence 3012LF and Selenium 100 watt horn. Not sure what the crossover is. don will build the whole thing from top to bottom, I will supply the K140.

[grumpy]

Foster horn is stuck in a lot of bass cabinets ... helps the snapping/popping
thing to come through. SWR, Eden, Ampeg all have had examples at one
time or another, IIRC. They seem to integrate better if there's something
between them and a 15 or 18" bottom (e.g. multiple 10" drivers). I mostly
leave mine off.

[Fred Sanford]

Foster horn is stuck in a lot of bass cabinets ... helps the snapping/popping
thing to come through. SWR, Eden, Ampeg all have had examples at one
time or another, IIRC. They seem to integrate better if there's something
between them and a 15 or 18" bottom (e.g. multiple 10" drivers). I mostly
leave mine off.

Yeah, I'd used a few horns in SWR, GK & (I think) Hartke cabs, and went with 10"s instead.

je

[jcrobso]

The guy who will build it is Don Oatman at Low Down Sound in Detroit. He pretty much builds bass guitar cabs and is very knowledgeable when it comes to bass cabs. I was just hoping to give him enough info to get started, although I'm sure he will have his own suggestions. The other cab he built for me is a 2-way, 112, horn cab with an Eminence 3012LF and Selenium 100 watt horn. Not sure what the crossover is. don will build the whole thing from top to bottom, I will supply the K140.

Since Don has experience ask him what he would recommend.

Maybe this combination would work. The high pass filter might have to custom made but that is not a big deal.
This driver.
http://www.parts-express.com/pe/show...number=264-204
And this horn.
http://www.parts-express.com/pe/show...number=264-306
Or this horn, JBL uses a horn like this on some of the PA line.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2572

[jnewmark]

Since Don has experience ask him what he would recommend.

Maybe this combination would work. The high pass filter might have to custom made but that is not a big deal.
This driver.
http://www.parts-express.com/pe/show...number=264-204
And this horn.
http://www.parts-express.com/pe/show...number=264-306
Or this horn, JBL uses a horn like this on some of the PA line.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=292-2572

Thanks for the info, everybody.

[A9X]

Unless you are dead cert on using the K140, I would look at greenboy's fEARFUL designs on Talkbass with a 3015LF and a 6ND410.
http://www.talkbass.com/forum/showthread.php?t=508659
http://www.talkbass.com/wiki/index.p..._12/6_%26_15/6

I had something similar prototyped (different drivers, similar concept) before I stopped playing out and it was the best rig I've had or heard.