Changing dipole baffle from 12" to 14"-Consequences?

[Eric H]

I am getting ready to assemble a pair of Adire DDR dipole kits that I've had laying around. I also will be building two bass bins that are 14" wide, and the DDR's will be on top. The DDR's are supposed to be 12" wide. What would the sonic implications be to my going with 14" baffles to match the bass bins?

Thanks, Eric.

[ThomasW]

Doing that lowers the baffle reinforcement frequency. I don't imagine it will make much difference in the overall performance

[Eric H]

Great, thanks Thomas.

[JoshK]

I just read that some German proved that a baffle 2.2 times the effective width of the driver in question is optimal for minimized diffraction effect. take that fwiw. I saw it mentioned on diyaudio.

[thadman]

I just read that some German proved that a baffle 2.2 times the effective width of the driver in question is optimal for minimized diffraction effect. take that fwiw. I saw it mentioned on diyaudio.

the mounting frame or the diameter of the speaker cone derived from its area?

[JoshK]

I'd have to look up the link...I got the impression that effective width was cone diameter or maybe including surround.

[Rudolf]

I just read that some German proved that a baffle 2.2 times the effective width of the driver in question is optimal for minimized diffraction effect.

The effective (sic) width is meant as the moving area of the driver aka Sd.
One has to keep in mind that this analysis was purely mathematical. And strictly speaking it relates to a circular baffle with the driver in its center only.
The more your real baffle departs from this assumption, the less you need to care about the findings.

The source

[Dennis H]

Thanks for the link, Rudolf. My German is a bit rusty but it sounds like he's saying 2.2*D should be the largest size to minimize diffraction but smaller is okay. Is that how you read it?

And of course, as you say, he's testing a circular baffle and assumes 'perfect' dipole drivers with no rear basket, etc., so real-world results will probably be different.

[Rudolf]

My German is a bit rusty but it sounds like he's saying 2.2*D should be the largest size to minimize diffraction but smaller is okay. Is that how you read it?

Exactly!
But you are not allowed to call your German "rusty" as long as you can understand anything of that prose.
In fact that paper is written more complicated than the theory it describes.