Baffle Shape for Smooth Frequency Response

[scottjoplin]

Hi, no problem. Yes, petals would be best, symmetry is important. I wonder how far one could go with the petals....... something based on fractals perhaps?

 

[NATDBERG]

Mount a driver in some romanesco broccoli (whatever it's called).

 

[Daihedz]

I wonder if anyone has tried somethings similar for OB, a bit simpler than flower petals

I once managed to iteratively "saw" out a perfect BUT2 highpass-behavior within +- 0.5dB with a open baffle, starting from an asymmetric logarithmic snailhouse contour. Along with a complementary electric BUT2 this provided a neat LR4 behavior. No kidding, it worked.

1. But it only worked straightly measured aligned with the driver axis.
2. And any asymmetric design will completely ruin constant directivity. So you better avoid linear snailhouse contours over 360° as in the example shown in this thread.

 

[Joseph Crowe]

I don’t think the shape (looking straight on-axis) will have much of an impact on the sound quality. For the cleanest sound the baffle needs to carefully transition the wavefront away from the driver. This improves the off-axis performance since edge diffraction isn’t causing artifacts due to stored energy. This shows clearly in a spectral burst decal plot or impulse response measurement.
Also, Olsen’s graphs were hand drawn based on guessing. I do not agree with some of them based on my own experience.

 

[Joel Wesseling]

For the cleanest sound the baffle needs to carefully transition the wavefront away from the driver. This improves the off-axis performance since edge diffraction isn’t causing artifacts due to stored energy.

"carefully transistion" - Have you determined a specific baffle profile that is best? Pic? thanks!

 

[Mattes]

Hi,


the careful transmission works indeed good. Difficult to measure, at least for me, didn´t succeed. But to my ears, it sounds better than any other baffle I tried (quite a few...), cleaner, no artifacts, better 3-D-illusion. Of course, this is very subjective.
The shape has no special formula or determination - just a smooth curve from the membranes exit angle to the very large roundover.


All the best


Mattes

 

[Juhazi]

Petal shapes work well, but are difficult to make. A ball or dome shape is pretty good at at preventing diffractions too. See the old B&W Nautilus and their modern tweeters. Designer or those was Laurence Dickie who is now designing Vivid Audio speakers.

 

[Joel Wesseling]

I thought maybe JC had some measurements to support a best overall shape.

Yes, quantifying the audible effect is difficult.

I have made spherical tweeter pods. Felt is installed around the front and flat on the tweeter faceplate. Fabulous sound.

I owned N801 for 2 years and had to unload them. They are extremely open but have several major issues that make them hard to live with. I believe the N tweeter holder is a bad design as there is no baffle for the dome.

Its nice to see creative ideas for dealing with baffle reflections. I like the style of this speaker that has diffusion machined into the baffle..