LCR with 12" full range in SEALED BOXES - help with little tips and tricks

[audfrknaveen]

Hello All,

I am about to build LCR speakers for home theater with 12" Full range drivers. SEALED BOXES with approx 2ft high, 14" wide and 9" deep.

But i am wondering if there can be little improvements i can do in the box design and driver position.

So here are my questions...

1. Please see the attached image with different driver placements.
Options 1,2 and 3 are divers placed in the center, top and near to one corner respectively. Which is better?

2. If the driver needs to be offset from the box center, are there any thumb rule dimensions for D1, D2, and D3?

3. Flush mounting the driver with the baffle Vs mounting the driver on the baffle makes any significant difference?

4. Rounding off the edges of the front baffle is good or doesn't matter much?

Can you help with my queries please ....

Thanks a lot in advance !!!

 

[GM]

View a speaker box as a tiny room and assuming it will only be minimally damped, we ideally want a good room ratio to sufficiently randomize its eigenmodes and then only damp to 'taste' one of each parallel walls.

Ditto the driver location at an acoustic or golden ratio offset.

Been years now, but all the math plus calculators were online, so imagine they still are + some new ones.

GM

 

[GM]

Every little bump, lip, corner, termination, etc., creates an acoustic mismatch which in turn creates a reflection [eigenmode], so while a relative few little ones get lost in the 'mix', 'God' is in the details, and at least the big ones should be attenuated as much as practical.

To be more than mostly cosmetic, corners need relatively huge radii, so the bigger the cab the larger the round over. I did one set that the baffle width round overs needed to be so large it wouldn't leave enough flat baffle to mount the horn, not to mention a time consuming PITA to do, so wound up cheating by cutting the corners at the appropriate diagonal, then just dealt with the little sharp edges. Later, the owner's wife made some built-up foam bumpers to give them a ~ Art Deco look.

GM

 

[audfrknaveen]

Dear GM,

Thanks a lot for very useful inputs.
May be il make a regular rectangular box like OPTION2 in the image.

Later i will see the possibility of adding large radius etc with additional additional foam board or some kind of cardboard etc.