I built a bass cab with a 15 on top and an 18 on bottom

[Codygx123]

I need help with a crazy idea
So I have this cab I built to house 2 speakers. A 15 inch, 4ohm 400watt 40DB low, and a 18 inch 4 ohm 400 watt 38DB low.
I play a 5 string bass and want to basically send the lower frequencies of the low B to the 18 inch with a lower DB rating and the rest to the wider range 15.
will a passive crossover solve all of the my problems? Or will it just work that way?
I plan on wiring it in series.

 

[basscooker]

I'm not sure this is going to work out.

I dont really have any specific instructions, but questions.... Are you sure those dB ratings you posted are correct?
What speakers, again? Did you model them? Are they sharing airspace? Let's start there.

 

[BasturdBlaster]

Yea, separate air space as a first!

 

[agedhorse]

I have no idea what you are talking about regarding your drivers.

If you are using a crossover (or want to or think you want to), you can't wire them in series or parallel. Each driver would be fed from the output of the crossover.

A passive crossover for the frequencies that MIGHT be useful is going to be both massive and expensive.

It looks like you don't have any experience with this, based on what you have posted. How much money are you willing to waste?

 

[Codygx123]

I'm not sure this is going to work out.

I dont really have any specific instructions, but questions.... Are you sure those dB ratings you posted are correct?
What speakers, again? Did you model them? Are they sharing airspace? Let's start there.

The are sharing air space, the are
Wharfdale 224d
And
Wharfdale
240?

I have no idea what you are talking about regarding your drivers.

If you are using a crossover (or want to or think you want to), you can't wire them in series or parallel. Each driver would be fed from the output of the crossover.

A passive crossover for the frequencies that MIGHT be useful is going to be both massive and expensive.

It looks like you don't have any experience with this, based on what you have posted. How much money are you willing to waste?

as much as it takes to get what I want
I’ve made speaker cabs before but this is the first time I’m doing something unconventional

I'm not sure this is going to work out.

I dont really have any specific instructions, but questions.... Are you sure those dB ratings you posted are correct?
What speakers, again? Did you model them? Are they sharing airspace? Let's start there.

 

[lz4005]

I need help with a crazy idea
So I have this cab I built to house 2 speakers. A 15 inch, 4ohm 400watt 40DB low, and a 18 inch 4 ohm 400 watt 38DB low.
I play a 5 string bass and want to basically send the lower frequencies of the low B to the 18 inch with a lower DB rating and the rest to the wider range 15.
will a passive crossover solve all of the my problems? Or will it just work that way?
I plan on wiring it in series.

dB is a measurement of volume, not frequency response.
If you're using a crossover the speakers aren't in series or parallel.
You have a lot of research to do before your project is even remotely possible.

What are you hoping to accomplish? People abandoned the myth that you need an 18 to reproduce the lows of a B string over 20 years ago.

 

[David Jayne]

Speakers ain't what they used to be. These days, bigger ones are usually louder. Without real in depth knowledge, that's about all you can count on.

 

[agedhorse]

Those Wharfedale model numbers are home hi-fi type cabinets and I don't see where you are getting an 18" and 15" from???

What exactly are you talking about, I'm even more confused now than before.

 

[agedhorse]

Speakers ain't what they used to be. These days, bigger ones are usually louder. Without real in depth knowledge, that's about all you can count on.

I'm not even sure that's true... all you can really say is that the bigger one is bigger.

 

[lug]

This is all I need to know about speaker design!

 

[Redbrangus]

You can't really get there from where you are. A simple high-pass filter could do the frequency-dividing part, but that can't be accomplished if the speakers are in series. Plus, as previously noted, the two drivers are sharing the same air space. Plus the drivers are home hi-fi speakers. You can't really get there from where you are.

It does appear to be a nice enough piece of construction, though. Good job on that.

 

[David Jayne]

I'm not even sure that's true... all you can really say is that the bigger one is bigger.

Fair enough. I was assuming that within a given model range the larger ones would be larger in order to be louder. But I don't know that.

 

[walterw]

I play a 5 string bass and want to basically send the lower frequencies of the low B to the 18 inch with a lower DB rating and the rest to the wider range 15.

on top of all the other reasons why this will probably not sound that good, if you did correctly use a real crossover between the two speakers, there would be no point in the top speaker being any bigger than like a 6" midrange driver

 

[lz4005]

on top of all the other reasons why this will probably not sound that good, if you did correctly use a real crossover between the two speakers, there would be no point in the top speaker being any bigger than like a 6" midrange driver

Which is exactly why you're supposed to finish the design before you begin construction.

 

[Bass_Pounder]

Back to the drawing board...………..

 

[Omega Monkey]

A 15 inch, 4ohm 400watt 40DB low, and a 18 inch 4 ohm 400 watt 38DB low.

Huh?

 

[And I]

If this were a "talk me out of doing this" thread i think you'd get a lot of helpful advice!

Looks like a fun project, but... The way you are going about trying to reach your stated goal is not going to get you there, no matter how you wire it together. You've chosen the wrong speakers and built the wrong box. Not to mention the entire premise of your stated goal ignores the basics of psychoacoustics...

 

[DJ Bebop]

I have no idea what you are talking about regarding your drivers.

If you are using a crossover (or want to or think you want to), you can't wire them in series or parallel. Each driver would be fed from the output of the crossover.

A passive crossover for the frequencies that MIGHT be useful is going to be both massive and expensive.

It looks like you don't have any experience with this, based on what you have posted. How much money are you willing to waste?

He said, "How much money are you willing to waste?"

 

[DJ Bebop]

Those Wharfedale model numbers are home hi-fi type cabinets and I don't see where you are getting an 18" and 15" from???

What exactly are you talking about, I'm even more confused now than before.

 

[Tim Skaggs]

For the cabinet to be extraordinary, it would have to be the size of a troll’s house.