Is this kind of bracing ok?

[mr_push_pull]

My box will be approx. 15x25x40 cm (internal dimensions), and the bracing like shown in the pic (W is woofer, T is tweeter, P is port, B is bracing).
My question is: is it OK to have the horizontal braces very close to the upper and lower walls, won't this create a helmholtz effect? The distance to the walls will be approx. 3 cm.

And if you're thinking that the middle brace will obstruct the air flow, I'll either drop it or cut a hole into it.

Thanks.

[richie00boy]

You would be much better just making one shelf that runs perpendicular to the walls with cutouts for airflow. Those side parts are serving no purpose in strength as they are so close to the walls. And yes I suspect they will turn your box into a bandpass box.