2x10 Eminence BP102 cab build

[jongor]

i have two of these drivers out of a pair of BFM cabs that I don't use so plan to put them together to make a 4 ohm bass cab.

I'm kind of rookie using WINISD but entered the driver info and modeled the cab to get started.

Using the Eminence cab build paper as a start I ended up with a 3.4 cu ft volume tuned to 42hz, 2 3"dia ports 4.2" long.

The db curve shows 44hz is at -3db.

The plan is to orient the drivers vertically with the ports between them.

Without a lot experience with cab design I'm not sure if this will result in a usable cab.

Should I add a mid driver?

I play 4 string in a funk band a occasionally use an octave pedal.

Is a high filter necessary?

I will be using the cab with a 300 watt Eden WT AMP.

Any info or remarks would appreciated!

[Invalid or Expired Link Removed]

 

[Rick James]

Put them in a 2x10 BFM Simplexx 10. There's a lot more to designing a cab than plugging numbers into WinISD.

 

[jongor]

Just checked out Bills website and don't see that the BP102s are used in that cab.

 

[pie_man_25]

A pair of those drivers would make a great 210. You'd want to use a mid and tweeter with them if you want any clarity for a good flat response. If you only use a tweeter you'll get a natural dip in the mids, those drivers aren't too middy, good drivers though, I'd say they're almost as good as the kappalite 10s, definitely better for the money IMO.

 

[Rick James]

Just checked out Bills website and don't see that the BP102s are used in that cab.

They are recommended in the plans.

 

[pie_man_25]

They are recommended in the plans.

If that's so, it would be a good idea, bfm puts a lot of thought into design. Which is why many of his designs are relatively unorthodox, as far as bass gear goes. That said though, he just pulled then out of a bfm cabinet, maybe he just did that because he wants something different

 

[jongor]

Im not against building a BFM Simplexx cab, the Bfm Tubas are too big for my car, and I don't have the proper PA gear to use them (bi-amp w/crossover).

I have seen other threads of people following the Eminence recommended cab plans with good result.

 

[Rick James]

The Eminence plans are fine so far as they go, but that's not very far. You're on your own where all the details are concerned, and its the details that make the difference. The sketchup models alone are more than worth the price of the plans, and the BFM forum sets the standard for support.

 

[lakefx]

I didn't use BFM plans for my build because I wanted to go through the whole design process. It was a lot of work, but TB is a wealth of knowledge and I even got bracing suggestions from Jeff Genzler once I had made a sketch up model.

 

[jongor]

So I am going to use the BFM Simplexx 10 plans, however I'd like to use a mid driver rather than a tweeter.

I know this is a loaded question, but how do I select the proper mid and high/low pass filter components to achieve this?

 

[Woodstockz]

So I am going to use the BFM Simplexx 10 plans, however I'd like to use a mid driver rather than a tweeter.

I know this is a loaded question, but how do I select the proper mid and high/low pass filter components to achieve this?

I have a BP102 in a 1.5 cu ft test box. I use it for testing mid range speakers. It sounds really good. More on that later.

The BP102 sounds good, is relatively cheap, and has a lot of bottom, which works well for funk. Add a tweeter for pops. For more versatile applications, some people refer to it as dark. IMHO, adding a mid is the right thing to do to make it sound more hifi.

Selecting the proper mid and crossover... Well, that is kind of a trick with this one, which can open up a pretty big can of worms. But if you spend a little time and work on it, you will get good results.

First, take a look at the frequency response chart. Note a the dip from about 250 to 700 Hz. That is the problem, unless you like that scooped sound. A lot of mids are crossed over around 1000 or 2000 HZ. So you you might want to get a mid that goes down lower than most other mids to cover the hole in the BP102 response. But there is also impedance and efficiency to match your woofers to consider when selecting the mid.

Then there is the problem with the crossover. You will need a steep crossover slope. And as the crossover frequency goes down, the price of the crossover components goes up. And since you are doing a 2x10, your speaker impedance is 4 Ohms. Most off the shelf crossovers are 8 Ohms. The Eminence PXB2:500 would work OK if you had an 8 Ohm load, but since your load is 4 Ohms, you have to make a custom crossover, or have one made. For calculating the values, you can use an online crossover calculator like this one...

2-Way Crossover Designer / Calculator

With this calculator, you can select your desired crossover frequency, and you can select a mid with a different impedance than your woofer.

I like the BP102, but I only use it for my experimentation in my garage. For funk? I can nail the intro to "If you want me to stay" with it. But since my test cabinet weighs a ton (3/4" ply) and the speaker is ceramic, and I have a rotator cuff issue, it never leaves the garage. I use neos for everything else. Since you have to do so much work to get the right mid and crossover, I have looked at other options. I prefer to use 12 inch deltalite neos or faital 12pr300s for just a little more money. But that's not an issue for you since you already have the speakers.

 

[jongor]

Thanks for the info!

Should I go as low as 250hz with the crossover?

 

[pie_man_25]

I have a BP102 in a 1.5 cu ft test box. I use it for testing mid range speakers. It sounds really good. More on that later.

The BP102 sounds good, is relatively cheap, and has a lot of bottom, which works well for funk. Add a tweeter for pops. For more versatile applications, some people refer to it as dark. IMHO, adding a mid is the right thing to do to make it sound more hifi.

Selecting the proper mid and crossover... Well, that is kind of a trick with this one, which can open up a pretty big can of worms. But if you spend a little time and work on it, you will get good results.

First, take a look at the frequency response chart. Note a the dip from about 250 to 700 Hz. That is the problem, unless you like that scooped sound. A lot of mids are crossed over around 1000 or 2000 HZ. So you you might want to get a mid that goes down lower than most other mids to cover the hole in the BP102 response. But there is also impedance and efficiency to match your woofers to consider when selecting the mid.

Then there is the problem with the crossover. You will need a steep crossover slope. And as the crossover frequency goes down, the price of the crossover components goes up. And since you are doing a 2x10, your speaker impedance is 4 Ohms. Most off the shelf crossovers are 8 Ohms. The Eminence PXB2:500 would work OK if you had an 8 Ohm load, but since your load is 4 Ohms, you have to make a custom crossover, or have one made. For calculating the values, you can use an online crossover calculator like this one...

2-Way Crossover Designer / Calculator

With this calculator, you can select your desired crossover frequency, and you can select a mid with a different impedance than your woofer.

I like the BP102, but I only use it for my experimentation in my garage. For funk? I can nail the intro to "If you want me to stay" with it. But since my test cabinet weighs a ton (3/4" ply) and the speaker is ceramic, and I have a rotator cuff issue, it never leaves the garage. I use neos for everything else. Since you have to do so much work to get the right mid and crossover, I have looked at other options. I prefer to use 12 inch deltalite neos or faital 12pr300s for just a little more money. But that's not an issue for you since you already have the speakers.

This is fairly accurate, I've really only seen the BP102's paperwork. It tends to want a very large ported cabinet, or a decently sized sealed cabinet. I'd say that two of them in a sealed box of about 2 cubic feet would be great for the lows, but like you've said you still have the dip in the lower to mid mids to worry about. if you were to go with a mid, like you say it would be a bit difficult finding the right one - I tried looking at 5" mids, but perhaps a 6" or 8" might be a little bit better to match sensitivity in the low to mid mids.

 

[Arjank]

You could counterbalance the 500hz dip a bit by choosing the appropriate baffle width. The baffle width is accountable for the bafflestep.
If the width is 18" you'll get a 3dB increase around 500hz which would compensate the dip nicely.

The response will then be ok to mate the two BP102's with a mid driver that takes over the duties somewhere between 800 - 1.2khz.

 

[Woodstockz]

Thanks for the info!

Should I go as low as 250hz with the crossover?

If you go too low, you begin to loose the benefits of the mid.

For 8 Ohms, the Eminence PXB2:500 crossover covers most of the hole at 500Hz.

Arjank has a great suggestion about the baffle step... I have not seen the BFM Simplexx 10 plans.

With a little head scratching, you can get a nice rig with the BP102.

 

[jongor]

Thinking about using the [Invalid or Expired Link Removed], crossed over at 250hz.

The Simplexx 2x10 uses corner vents, not a shelf.

 

[Arjank]

Thinking about using the [Invalid or Expired Link Removed], crossed over at 250hz.

I can't recommend crossing that low.
Btw. the Alphalite 6a is smoother in the mids and has better efficiency. I think it's a great partner for two BP102's when crossed at 800hz (which is much easier to achieve with a passive crossover then 250hz).

 

[jongor]

Why, because of the crossover?

The mid dip of BP102 is 250-700, crossing the mid at 800 wouldn't do anything for that.

 

[will33]

Arjank's on about the baffle step.

Eminences regular Alpha6 plays pretty well with a pair of bp102's. Good candidate for a 800-1khz crossover.

Bp102's can go way deep in a big box but I think you'll find about 3 cu.ft. ( ~85 liters ) would get a pretty deep sounding yet still managable size 210 bass cab.

 

[Woodstockz]

I can't recommend crossing that low.
Btw. the Alphalite 6a is smoother in the mids and has better efficiency. I think it's a great partner for two BP102's when crossed at 800hz (which is much easier to achieve with a passive crossover then 250hz).

Faital 6FE200 is also more efficient.