Triangle Baffle?

[southpaw17er]

How would the diffraction look for a driver mounted in a triangular baffle?

Assuming a sphere is the best for diffraction, the end of a cylinder (or a 2D circle) the worst, and a rectangle somewhere in the middle, where does the triangle fit (both equilateral and acute or obtuse)??

I can't seem to find this mentioned anywhere...

Thanks in advance.

Ted

[Vikash]

The cylinder is worst assuming the driver is mounted in the centre because all edges of the baffle are equidistant from the driver edge. Mount if off-centre and the story changes.

So you can see that a triangle baffle has potential if you can spread out the driver to baffle edge distances.

Search for a program by one of our members called 'the edge' IIRC. You should be able to simulate this for yourself

[Vikash]

here it is: http://www.tolvan.com/edge/

[southpaw17er]

Thanks for the info Vikash, very useful program.

But what about a spiral baffle, in which the center of the driver is a different distance to all parts of the edge of the baffle (as seen in my artistic attachment).

Any ideas, since I can't simulate this in the program.

[Variac]

It depends on how you are using the baffle.
Are you hanging it in the air? Set on top of a bass box?
On the floor?

I have considered the same issues. I am using a rectangular one now which actually has quite a few different distances, so really isn't bad.

Lets think of a variety of possibilities.

[poptart]

I'm a newbie, but I've been wondering about the same thing, open baffle shapes. It seems the spiral, or a mirrored one like a cardioid would do the job, but would it be noticeably better than a rectangle to make it worth the added work?

I guess I don't understand why these peaks and valleys happen, I think it has something to do with the distance from the speaker to to the baffle edge being an even multiple of the wavelength of certain frequencies, but I can't clearly picture what's happening. If anyone could explain with the basic case of a speaker in the center of a round baffle it would really help me out

I also wonder why the baffle is always flat, what happens if you give it some thickness? If you move from the speaker in the center of a flat baffle case to a speaker in the "hole" of a donut, what changes? (please don't say everything )

[Vikash]

Originally posted by southpaw17er
Thanks for the info Vikash, very useful program.

But what about a spiral baffle, in which the center of the driver is a different distance to all parts of the edge of the baffle (as seen in my artistic attachment).

Any ideas, since I can't simulate this in the program.

I made the observation many moons ago:
Here's an animation that attempts to illustrate the concept of baffle edge diffraction for various baffle shapes.

It requires a SVG Plugin plugin (if it's not already installed in IE).

As mentioned, any close room boundaries can extend the baffle.

[Vikash]

Originally posted by poptart
I'm a newbie, but I've been wondering about the same thing, open baffle shapes. It seems the spiral, or a mirrored one like a cardioid would do the job, but would it be noticeably better than a rectangle to make it worth the added work?

I guess I don't understand why these peaks and valleys happen, I think it has something to do with the distance from the speaker to to the baffle edge being an even multiple of the wavelength of certain frequencies, but I can't clearly picture what's happening. If anyone could explain with the basic case of a speaker in the center of a round baffle it would really help me out

I also wonder why the baffle is always flat, what happens if you give it some thickness? If you move from the speaker in the center of a flat baffle case to a speaker in the "hole" of a donut, what changes? (please don't say everything )

I'm no expert but I'll give it a shot.
Of all the baffle shapes usually described, the sphere is the only one considered on all three axis. The point here being that the front wave has a more gradual slope in merging with the rear wave as the edge of the baffle is reached thus producing a smoother baffle step transition.

The other shapes are concerned with having different lengths from driver edge to baffle edge (although the fall off is sudden) to again try and smooth out the half-space to full-space transition. This is why rounding over baffle edges (on a bog standard rectangular baffle) is a good idea, although it is requires a large radius for any real effect, and also mounting drivers off centre.

But how many big commercial rectangular baffle designs do this...

[Vikash]

A good starting point: http://www.t-linespeakers.org/tech/b...intro-bds.html

[poptart]

Thanks, that explains what's happening in the low frequencies well. I guess this thread isn't about open baffle speakers, so my question about what causes the peaks and dips in the higher frequencies isn't in the right place here.