HI Fosty 47,
Trust me, you don't need to design a crossover larger than 18dB / octave, and even then, only if you plan to use it for concert sound systems.
For home use, 6-12dB/octave will be more than sufficient. The speaker drivers themselves provide some filtering due to their characteristics.
For a 2-way system, you could pretty much run the woofer right off of the incoming line from the amp.
For a 3-way system, you might want to be a little more daring.
Again, as I mentioned before, the characteristics of the individual drivers will determine if you need to include a Zoebel network, amongst other components, into your crossover network.
When I was designing speaker systems in the past, we used POLK audio speakers as one of our references for design, only becaude they were very popular, and we had to compete with them. Those speakers had very complicated crossovers, due to the multiple networks in place across and in series with their drivers, and all to compensate for the characteristics of the individual drivers, themselves.
In my opinion, they still sounded like "C**P". ( And I can prove it, compared to our designs.) Anyway, speakers and the way they sound, are a very subjective subject, and as such, if you are designing a speaker system for yourself, for your home, for serious music listening as opposed to "Home Theatre" use, then, the system will have to be designed accordingly, which means, give us all of your deepest, darkest, listening room, and speaker system requirement details (Muahaaa!!!!!) ( evil laugh! )
We will CREATE!!!!!!!!!!!!!!!
Sorry, it's been a long day...
I hope that "Audio Guru' might step in with his two pence worth, then again...
Remember, the cabinets are required to be designed around the speaker drivers, and what you want them to do.
The standard way to design speaker systems is to:
1- Determine what the speaker system/cabinet is to be used for, that will tell you what kind of SPL levels that you need to achieve. Is a home system, or a Professional installation/PA system ?
2- What frequencies are you trying to cover with the sysytem/drivers? Are you designing a Booming/Thumping system, or is this going to be a speaker system to listen to music at home, in private, undisturbed, etc.,
Both types of speaker systems require a crossover of some type, and amplification of some type. ( Sometimes a lot of amplification )
3.After that, it can get complicated
Before I go any further, please tell me/us what exactly, you are trying to accomplish.
Cheers,
Andy