Inverting baffle step and diffraction effects?

[johnnyrichards]

Just want to do a few experiments, is there a way to "invert" the effects of baffle step loss and diffraction effects on raw, on-baffle measurements?

[Sydney]

The 6db adjustment for the baffle would be easy, for the effects of diffraction not so; it would depend on the geometry of the cab and would vary at different points off axis, and signal EQ cannot be selectively applied to particular directions and orientations.

[neildavis]

Just want to do a few experiments, is there a way to "invert" the effects of baffle step loss and diffraction effects on raw, on-baffle measurements?

It's easy to do if you have a routine that can model and properly calculate the diffraction effects of the baffle. I've got a good diffraction routine, but what you are asking for is in the "tools" category. Is there much use for that type of tool?

[johnk...]

You could measure the driver on the baffle and then measure it when mounted in a wall (2PI) and then subtract the 2Pi data from the baffed result.

[johnnyrichards]

You could measure the driver on the baffle and then measure it when mounted in a wall (2PI) and then subtract the 2Pi data from the baffed result.

I wonder what my wife would say if she came home from work and I have turned one bedroom wall into a measurement baffle? :)

I was hoping for a software solution, I just want to get an idea of how much the woofer cavity is affecting the tweeter response.

[johnnyrichards]

It's easy to do if you have a routine that can model and properly calculate the diffraction effects of the baffle. I've got a good diffraction routine, but what you are asking for is in the "tools" category. Is there much use for that type of tool?

I would find a use for it, but I am a nerd like that :D

[neildavis]

I was hoping for a software solution, I just want to get an idea of how much the woofer cavity is affecting the tweeter response.

I don't think there has been any attempt to model the effect of the woofer cavity on tweeter response, and there won't be a software solution until a good model is available and all of the parameters are identified and properly factored. You are going to have to take measurements and subtract out the difference.



I wonder what my wife would say if she came home from work and I have turned one bedroom wall into a measurement baffle? :) .

Tell the wife she is going to have to suck it up for the sake of science :D

[johnnyrichards]

I don't think there has been any attempt to model the effect of the woofer cavity on tweeter response, and there won't be a software solution until a good model is available and all of the parameters are identified and properly factored. You are going to have to take measurements and subtract out the difference.

This is why I was hoping to find a software tool that will take out the baffle influence on my measurements, actually. I just want to get a feel for what the woofer is doing to the tweeter. I recently measured a project I did in pure simulation and noticed some oddities. So I re-ran all of the simulations from the CLIO files and arrived at the same conclusion: the woofer is impacting the summed response enough to make the simulations not super-accurate.




Tell the wife she is going to have to suck it up for the sake of science :D

:D

[tom_s]

This is why I was hoping to find a software tool that will take out the baffle influence on my measurements, actually. I just want to get a feel for what the woofer is doing to the tweeter. I recently measured a project I did in pure simulation and noticed some oddities. So I re-ran all of the simulations from the CLIO files and arrived at the same conclusion: the woofer is impacting the summed response enough to make the simulations not super-accurate.




:D

You have probably already though of this, but you could make a wooden disc that bolts flush over the woofer hole. That would at least give you the with woofer and without woofer responses. I think you can subtract one frd file from another in Speaker Workshop to give you the result.

[johnnyrichards]

You have probably already though of this, but you could make a wooden disc that bolts flush over the woofer hole. That would at least give you the with woofer and without woofer responses. I think you can subtract one frd file from another in Speaker Workshop to give you the result.

Maybe just use some duct-tape instead... Hmmm... Good idea, Tom.

[Jeff B.]

Just want to do a few experiments, is there a way to "invert" the effects of baffle step loss and diffraction effects on raw, on-baffle measurements?

My earlier version of the Response Modeler had an invert function for the diffraction model, but I took it out for version 3 because I was getting a lot of comments regarding how much it confused people, and I felt it had very limited application. I included it originally to do just what you described - to take measured data that had baffle effects and back them back out to leave something like an infinite baffle response. As it has been pointed out though, there are things that create diffraction that go beyond cabinet edges, like the woofer cavity and flange or surround edges. So, this method would not actually work as well as you might think.

Jeff

[OlderMongrel]

You have probably already though of this, but you could make a wooden disc that bolts flush over the woofer hole. That would at least give you the with woofer and without woofer responses. I think you can subtract one frd file from another in Speaker Workshop to give you the result.

I tried this, pretty interesting results.

http://techtalk.parts-express.com/showthread.php?t=225356

John

[DDF]

I tried this, pretty interesting results.

http://techtalk.parts-express.com/showthread.php?t=225356

John

Saved me a post. Oh, wait a minute...

Dave

[johnnyrichards]

I tried this, pretty interesting results.

http://techtalk.parts-express.com/showthread.php?t=225356

John

That is right where my problem areas were on the builds I did purely from simulations.

[Sydney]

...As it has been pointed out though, there are things that create diffraction that go beyond cabinet edges, like the woofer cavity and flange or surround edges. So, this method would not actually work as well as you might think.
Jeff
Indeed, this is an important distinction.