How to model 3-way loudseaker in WinISD

[dih1118]

In my other thread (3 Way Loudspeaker Design) people recommended that I model my 3 way sealed loudspeaker in WinISD.

However, I can't figure out how to model 3 speakers in one enclouse.

All I can do is model each component separately in the same size enclosure.

Could someone tell me how to do this? If WinISD doesn't allow this, could you recommend me a program that will? I also need a program that will model the accompanying 3 way crossover.

I am not looking for a handout, I just need a program to model the speaker, and I'm sure you guys know of one.

Thanks
-David

[pinkmouse]

Hi David

Ok, a few simplified basics first. T/S parameters are only really useful for calculating the low end response of a driver, and this is what all design programs that use them will simulate.

For a three way speaker, each driver should be in a separate enclosure to avoid interaction. However, most tweeters, and some mid drivers have a sealed back, and thus can be mounted in a common enclosure.

So, you probably don't need to worry about the tweeter's T/S parameters. The mid needs to be in a box that gives a gentle roll off below the crossover point to the woofer, you don't need to extend the low frequency response, just get a smooth roll off, that way you will get better results from the mids.

The woofer is the driver you need to really model, and there are many posts here and elsewhere as to how to go about it, so just do a bit of research to get a good handle on what you need to look for.

However, IMHO, you may be a bit out of your depth starting as a newbie on a three way design, as they require a lot of optimising and can be tricky to get working properly, especially in the crossover. I have been playing with speakers for over 15 years, and it was only about 6 years ago I finally designed one that really worked the way I wanted it to. I would suggest starting with a smaller two way to get started, after all, you can always use them in the bedroom, or as rear speakers later in a HT setup.

[dih1118]

Just to be perfectly clear - you're saying each speaker component needs a separate chamber inside the overall enclosure to function properly? The mid I'm using does not have sealed back. But I've never seen a three way enclsoure with three separate chambers ....

[Vikash]

you're saying each speaker component needs a separate chamber inside the overall enclosure

yes.

The response from a driver depends on its enclosure, and each type (woofer, midrange, tweets) requires its own enclosure within the overall cabinet. Generaly speaking tweeters can do without as they are already sealed. But you should probably seal it from the rest of enclosure anyway to prevent unwanted vibrations affecting it.

But I've never seen a three way enclsoure with three separate chambers ....

I don't think I've seen without at least the woofer/midrange seperated.

[dih1118]

Thanks for your help guys - this really clears things up.

I wanted to do three separate chambers but I had never seen it done. Perhaps I should stop opening up old Sony speakers as my baseline.

[pinkmouse]

Originally posted by dih1118
Perhaps I should stop opening up old Sony speakers as my baseline.