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Need Help From Speaker Cab Gurus

Low Class

Low Class

Jul 4, 2005
4,418
2,750
Disclosures
Gasaholic
#1
I have a 15" ported bass cab that I want to put a speaker in and need help from anyone familiar with using WinISD.

The internal dimensions are 13.5"D x 21"W x 15"H. It has 2-3" tubular ports that are 7" long each.

There are 2 speakers I am considering.
The first is an Eminence CB158. Here are the specs:
[Invalid or Expired Link Removed]

The second is a CA154. Specs:
[Invalid or Expired Link Removed]

I realize that one is 8 ohms and the other is 4 ohms. The CB158 is my preference, but I want to use whichever would require the least modification to the cab. The CA154 is also chosen because I already own one.

Any help is GREATLY apprecaiated. If anybody needs anymore info let me know. Also any other speaker recommendations are welcome.
 
Last edited:
#2
I'm getting 2.4 cuft, 40.95 tuning. What I'm coming up with for the CB15 is that you need another speaker above bass freq's. You could track down a prebuilt crossover, or make your own, but either way, you're hitting your -6dB at around 900 Hz. I'd really want to see the -3dB or lower for xover, though, which would be around 600hz max. I didn't do the CA154, but it looks to me this box won't like the CB15. Is anybody else coming up with different/better results?
 
#3
I can't make it all too pretty no matter what I try. Nothing will change that it needs something up higher, either. I even doubled the box size to see what would happen, raised the tuning to shorten the port length, eliminated one of the ports, nuthin'. I could get it looking like a good sub, but with that thing falling like a rock above 600Hz, I just don't see it working by itself for bass guitar. Maybe someone will come along with better ideas.
 
#4
basscooker said:
I can't make it all too pretty no matter what I try. Nothing will change that it needs something up higher, either. I even doubled the box size to see what would happen, raised the tuning to shorten the port length, eliminated one of the ports, nuthin'. I could get it looking like a good sub, but with that thing falling like a rock above 600Hz, I just don't see it working by itself for bass guitar. Maybe someone will come along with better ideas.
Click to expand...


Dang!! I was afraid of that. If I come across any other speaker candidates I'll post them. Thanks!!
 
#6
Well I just used Kappa 15 already entered in the library, not labeled as 15A, so it could be very different. With that, it appears to be a far sexier result, like enough that maybe no modifications would be necessary. I'd enter the specs from that link to be sure, but you'll see. There's no trickery going on here, just enter them. Plug and play, you'll figure it out, really.
 
#7
basscooker said:
Well I just used Kappa 15 already entered in the library, not labeled as 15A, so it could be very different. With that, it appears to be a far sexier result, like enough that maybe no modifications would be necessary. I'd enter the specs from that link to be sure, but you'll see. There's no trickery going on here, just enter them. Plug and play, you'll figure it out, really.
Click to expand...

Thanks!!
 
#8
FWIW, WinISD isn't much accurate when you get into the mids and higher where the driver and box don't really interact much.

Use it to predict things up to a couple/few hundred hz, and then just mentally splice the response chart from the driver datasheet in for the mids and highs.

The CB158 is on the warmer side of tone, but can still have definition on its own, up to 2500hz or so.

2.4 cu.ft. is small for any ported 15 really.
 
#12
chienmort said:
To be fair Will it is not just WinISD but all speaker sim programs work only on the lows. You need to look at the graphs on the spec sheet for the mids and higher. Also look at the off-axis response if given.
Click to expand...


Good to know. I don't have much experience with a bunch of different modellers. Gotten good/predictable results using the combination od WinISD and response charts.

It can show you a bit about how different specs affect things. For example, increase Le or listening angle and it rolls out more highs, so it's showing you the effect of doing that, but doesn't mean that particular result is accurate for your particular speaker.
 
#13
Actually, that CA 154 would have a ~2dB hump around 120-180Hz, which is a tad boomy but probably workable. F3 is around 65Hz, fine for a 4 string. If you already have it, I see no reason not to try it.

CB15 would have a smaller hump but a similar f3. Either one should work, I think.

As noted, this is a small box for a 15. It is not what I would build for one of these, but it will work.
 
#14
basscooker said:
I'm getting 2.4 cuft, 40.95 tuning. What I'm coming up with for the CB15 is that you need another speaker above bass freq's. You could track down a prebuilt crossover, or make your own, but either way, you're hitting your -6dB at around 900 Hz. I'd really want to see the -3dB or lower for xover, though, which would be around 600hz max. I didn't do the CA154, but it looks to me this box won't like the CB15. Is anybody else coming up with different/better results?
Click to expand...
I agree with the calculation for box size, although you need to reduce that value a bit for the driver and ports. Close enough, though.

I agree with the others though that you can disregard the box effect above 400-500Hz and just use the manufacturer's chart above that.
 
#18
Someone correct me if I'm wrong, but from CB158 cab design sheet it seems that the medium box design may come close if I change the ports to 4" diameter.

Here's the link

[Invalid or Expired Link Removed]
 
#19
You can tune the box up by shortening the 3" ports you have now (or down by lengthening them). I rounded your box size to 2.25 (interal volume less 10% for speaker) and came up with ~43Hz with 2- 3" x 7" ports. The box you're referencing has Fb=50. If you cut the 3" ports to about 4.5" then you'll get close to that tuning.

There is a risk that 3" ports could chuff (make audible noise) at high volume levels, depending on port flare and how good a match the speaker is to that particular tuning. A larger area port reduces that risk.

Some people say that WinISD port calculations are off, but they're close.
 
#20
INTP said:
You can tune the box up by shortening the 3" ports you have now (or down by lengthening them). I rounded your box size to 2.25 (interal volume less 10% for speaker) and came up with ~43Hz with 2- 3" x 7" ports. The box you're referencing has Fb=50. If you cut the 3" ports to about 4.5" then you'll get close to that tuning.

There is a risk that 3" ports could chuff (make audible noise) at high volume levels, depending on port flare and how good a match the speaker is to that particular tuning. A larger area port reduces that risk.

Some people say that WinISD port calculations are off, but they're close.
Click to expand...

So if I go with 4" ports what would be the optimal length?
 

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