My first BFM build

[profwacko]

I've had the plans now for nearly three years (just got an updated CD. TVM, Bill), and I have finally gotten around to building something.

I wanted a small cabinet to play electric piano and a Hammond clone through, so I've started with an XF210.

I picked up a used pair of JBL E-110s (there's not any new ones any more that I could find) for $150.

I had used a small cabinet with two of these in it for exactly this purpose in the past, so I figured it would be even better in a cabinet with better dispersion.

So, tell me what you think:









I decided to spring for the Line-X on my first attempt mostly because I just didn't have the time to experiment with something else. It was a little more expensive than I had thought ($45), but it really adds to the perceived professionalism of the cabinet. It is also a trifle shinier than I thought it would be.

Like the rounded fronts? I have a formula to calculate the radius of the circle necessary for a given extension amount for a rounded front based on the cabinet width. I'll post it elsewhere if no one is scared off by raw naked trigonometry. In other words, if your cabinet is 23" wide and you want a 2" deep rounded front, your radius would be 34". This will work on any cabinet.

Here's a 3D rendering of what I thought it would look like sitting on the rack that powers it:


It's still missing the metal mesh grille and the handles.

I can't wait to try it out at rehearsal tomorrow night.

I also can't wait to build something else. Maybe my ex-DJ buddy will jump back into the fray again...

-Jack

[Harley]

Lookin' good for your first cab build!

[Scott Brochu]

yes, very good.

[David Carter]

Nice work. The LineX finish looks great.

Like the rounded fronts? I have a formula to calculate the radius of the circle necessary for a given extension amount for a rounded front based on the cabinet width. I'll post it elsewhere if no one is scared off by raw naked trigonometry. In other words, if your cabinet is 23" wide and you want a 2" deep rounded front, your radius would be 34". This will work on any cabinet.

Please do share...

[profwacko]

Thanks very much for the kudos, guys.

I suppose that it's only fair to add that this is my first BFM build, but definitely not my first cabinet build.

I still have those 15" 2-way reflex cabinets from 1986 somewhere or other...

>>Please do share...

CAUTION!! RAW NAKED TRIGONOMETRY WILL BE SHOWN BELOW!!

SENSITIVE PERSONS SHOULD STOP HERE!!

Ok, buckle up, trig fans.

Let's say we want a rounded front on our 23" wide (W) cabinet that extends out beyond the straight line front edge by 2" (X).

First, we need to calculate the length L of the line from the center of the rounded portion back to one of the front corners.

So, L = SqRoot { (X squared) + (W squared / 4) }

Now, we need the angle B = ACOS( X / L)

We also need angle C, which is at the center of our big circle we will be drawing.

C = 180 - ( 2 * B)

So, we're down to the final part, which is the calculation of the radius (R).

R = L * sin(B) / sin(C)

In our example where W = 23 and X = 2, L = 11.673, B = 80.134 degrees, and C = 19.73 degrees.

So, R = 11.673 * .9852 / .3376 = 34.06".

If you are using the Calculator accessory on your PC, be sure you are doing calculations in degrees and not radians or grads.

I will post a graphic that will make this a lot more clear a little later today.

Also, I have an Excel spreadsheet with the calculations already present.

Shoot me a private email, and I'll send it along.

-Jack

[Harley]

CAUTION!! RAW NAKED TRIGONOMETRY WILL BE SHOWN BELOW!!

SENSITIVE PERSONS SHOULD STOP HERE!!

Ok, buckle up, trig fans.

How about setting this up in an Exel spreadsheet !!! so Scott and I can be lazy and just punch in the 2 numbers

[David Carter]

CAUTION!! RAW NAKED TRIGONOMETRY WILL BE SHOWN BELOW!!

SENSITIVE PERSONS SHOULD STOP HERE!!

Ok, buckle up, trig fans.

How about setting this up in an Exel spreadsheet !!! so Scott and I can be lazy and just punch in the 2 numbers

He's already done that. He sent it to me the same day he posted...

Also, I have an Excel spreadsheet with the calculations already present.

Shoot me a private email, and I'll send it along.