Math Question on speakers

[niget2002]

First, let me say this question is NOT the normal "series/parallel" type of question.

I'm wanting to use a normal schematic test software to play around with filter design... It's more for an educational purpose than anything else.

I also like to use linux, which means my software choices are a little more limited.

I've recently found a pretty nice circuit simulation software called qucs. It has its pluses and minus, with one of the big minuses being it has no model for a speaker.

Does anyone know where I can find the mathematical models of a speaker so I might try and create one?

qucs has the really nice feature of being able to have mathematical equations injected into a circuit

[J-Dub]

Im probably completely wrong here as this is a little out of my realm but i'll give it a shot.
I remember when searching for crossover design information on google i found a very informative site. I will try to post again if I find it. The guy on there did model a driver as a circuit but i think it will be different for each driver. the voice coil has its own inductance and the driver has its own resistances if im not mistaken. That's about all I can share untill I find that site again.
Good luck.

[littlesaint]

Im probably completely wrong here as this is a little out of my realm but i'll give it a shot.
I remember when searching for crossover design information on google i found a very informative site. I will try to post again if I find it. The guy on there did model a driver as a circuit but i think it will be different for each driver. the voice coil has its own inductance and the driver has its own resistances if im not mistaken. That's about all I can share untill I find that site again.
Good luck.

Was it this?

http://sound.westhost.com/lr-passive.htm#s3.1.1

[niget2002]

That's a good link, littlsaint!

I found a similar one on another site... That gets me the impedance graph for a speaker. Now, to pull out the old books for getting from the impedance graph to an amplitude one.

[littlesaint]

Being a newb at crossovers, I found that article very educational. Remember that the values given in the figure just an example, and in the real world, the values would change depending on the driver.

[J-Dub]

Thats exactly what i was talking about Littlesaint!
Great find!

[JonMarsh]

I added that link to the Elliot Sound Products page on Passive Crossover Design to the Reference Sites in the Missions Accomplished sticky.

I've seen this page a few times before but keep forgetting about it when someone needs a good reference to the basics.

~Jon

[niget2002]

That link worked well for getting me an equivalent network for a speaker.

I had to pull out the old college books to remember how to measure impedance from that. I'm still looking for the rest of the equations I want (phase and amplitude).

Qucs' ability to inject any equation into a circuit is very nice and interesting at the same time. It also has the ability to do parameter sweeps to help optimize a circuit.

[niget2002]

I also found this site very helpful:

http://www.geocities.com/f4ier/vented.htm

It has a link to the origionator of the topic and he has a pdf file on his site that talks about building SPICE models of elector-mechanical devices.

[Dennis H]

http://www.linkwitzlab.com/thor-design.htm