Originally Posted by armystud0911
Designing speakers takes skill and a lot of experience, which is why very few people, even in DIY do it.
He isn't kidding. I'd hate to add up the hours I've spent learning, measuring and building. Its a deep subject that takes a multi-disciplinary knowledge base. You also need tools that have a learning curve and will spend a lot of time making bad speakers before you make good ones.
Some hints to get you on the way:
#1. Measure your drivers in the enclosure you are going to use them in. You should have a basic idea of how they are to be used from Manf. specs so build the enclosure. Do your measurements outdoors, with the enclosure about 8ft off the ground. I built a support for doing this so that I get good clean measurements. You have to start with good clean data to get good repeatable results.
#2. Measure FR for the drivers in the enclosure they are to be used in @ about 2M (more for something like a line array). Make sure your well into the far field of the loudspeaker. Set your levels and take one measurement, then swap to the other driver without moving the mic or changing levels. Take the second FR, if your doing a 3-way take the third driver FR measurement, etc....
#3. Measure the Z in the same set-up but obviously you can take your proto -box off the stand.
I also like to get off-axis measurements for the drivers while its in the same position. That way you can model the off-axis data with the real off-axis measurement. I can swap between measurement data with a given crossover and see how it looks with both the on/off axis measured data (the Z doesn't change
Then you build something and re-measure to see how close you are to the model. Then you start the listening process to "voice" it to taste. I re-measure multiple times in the voicing process.
Lots of fun but it takes a ton of time and the better you understand the reasons for the FR & Z the better you are at making good choices in terms of design tradeoffs. The better you understand the underlying reasons for non-linear distortion and what is & is not audible, the better your chance at getting a good design.