Hi Juha
I’ve used this for speaker building for a while now.
http://www.speakerworkshop.com/
There are more complicated and more accurate applications out there but they cost money, sometimes lots.
You will of course need a decent microphone, preferably two.
An impedance test jig is also a great help.
My view is, there comes a point when the measuring has to stop and you need to start listening to the speakers in the environment you’re going to use them in.
I find Speaker Workshop is perfectly adequate to get you to that “listening” point.
Single spur balanced Mains. Self built music server with 3 seperate linear PSU, Intel i5, 16 GB RAM no hard drive (various Linux OS). Benchmark Dac2 HGC, single ended XLR interconnects/Belkin cable. Exposure 21RC Pre, Super 18 Power (recap & modified). Modded World Audio HD83 HP amp. Hand built Monitors with external crossovers , Volt 250 bass & ABR, Scanspeak 13M8621 Mid & Scanspeak D2905/9300 Hi. HD595 & Beyer 880 (600 ohm) cans.
The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.
-Bertrand Russel
John.