Are angled braces necessary?

[PWatts]

I'm busy building a pair of MTMs with built-in active subs. To make the cabinet rigid, they're rigged with braces, and lots of sub-compartments (some as small as 2litres). This lets each driver "see" a complex maze instead of just a rectangular enclosure. Problem(?) is, though a complex cabinet, all the angles are 90degrees. With all the precision work required, angles braces would have been almost impossible without subcontracting a professional.

Question is: Considering the magnitude of small interconnected mini-enclosures as well as the effect of damping material, would angled braces really have made any difference?

Another question: The sealed (MTM) compartments are stuffed with fibreglass and the backpanel lined with egg-crate foam. The ported (subwoofer) enclosure is lined with egg-crate foam and a very light fibreglass stuffing behind the driver. Any improvements that can be made on this (without audio-specific materials such as Deflex)? How about a mixed cocktail of long-fibre wool, polyurethane, fibreglass, dacron etc. to get the best of all their properties?

Thx,
Pierre

[leadbelly]

I'm busy building a pair of MTMs with built-in active subs. To make the cabinet rigid, they're rigged with braces, and lots of sub-compartments (some as small as 2litres). This lets each driver "see" a complex maze instead of just a rectangular enclosure. Problem(?) is, though a complex cabinet, all the angles are 90degrees. With all the precision work required, angles braces would have been almost impossible without subcontracting a professional.

Question is: Considering the magnitude of small interconnected mini-enclosures as well as the effect of damping material, would angled braces really have made any difference?

I don't understand. Are you saying that you took an existing design with complex internal bracing and modified it by shifting the braces around so that all cuts are 90 degrees? I don't think anyone can answer this without you identifying the design.

[PWatts]

No, no. It's my own design. I'm just curious why several people go through all the trouble to use angles corners & braces, while several designs work perfectly with 90-degree angles. Does people use them only for peace of mind, as dampling material plays a far bigger role.
Pierre

[leadbelly]

angles corners & braces

I still don't understand. Do you mean chamfers? That's when the edges are bevelled or rounded over so they are not sharp anymore.

[PWatts]

No, not chamfers- they are used on the baffle to counteract diffraction. I mean the inside shape. Some people shape the cabinet so that none of the joints (i.e. between baffle and top) are not 90 degrees but say 70, because it will minimise standing waves. This makes sense for an undamped box (especially if one dimension is a multiple of another), but damping material will IMO make a much larger difference than angled corners.
Pierre

[phase_accurate]

He is talking about something that was called a "matrix" by B&W.
I am currently working on a prototype cabinet as well that is using a rectangular stiffening matrix. I think this is still much better than no stiffening at all or the use of just some very simple braces.
I don't know if it is really worth the hassle to make non-rectangular joints. There will be a difference for sure but I don't know how large.

Regards

Charles