For every sound source in box you need SPL and impedance data. Both kind of data have to be with phase data. There is no possibility to simulate reality without phase data. On the other hand untill you are not able to get appriopriate data you can play with zeros as phase data. It is one step closer to reality than calculators and you also increase your experience.
There are at least a few ways to get those data. One of the best is get your own measurement equipment. The cheapest (~$650) but still professional set I found on the market, you can see here:
You can also try find on the net files with extentions 'frd' for SPL and 'zma' for impedance data. In this case you have to analyze the conditions in which the measurements were made. In some cases you can recalculate those data by yourself for example in case for different distances.
Below you can see examlple of SPL and impedance data.
Freq dB Phase 19.95 66.93 -143.35 21.13 59.15 -15.99 22.39 52.02 147.59 23.71 55.76 -169.41 25.12 56.21 -128.38 26.61 57.82 -149.67 28.18 59.44 -155.28 29.85 63.66 -126.75 31.62 64.33 -139.55 ............................... ............................... ............................... ............................... 17782.72 65.67 -174.81 18836.41 60.65 -130.03 19952.54 61.08 -176.38 21134.80 55.56 -170.62
Freq Ω Phase 19.95 11.25 45.30 21.13 11.96 46.45 22.39 12.83 47.91 23.71 13.83 49.12 25.12 15.08 50.25 26.61 16.70 51.15 28.18 18.84 51.78 29.85 21.88 51.46 31.62 26.24 49.79 ............................. ............................. ............................. ............................. 17782.72 47.94 58.63 18836.41 49.73 59.03 19952.54 51.44 59.56 21134.80 52.88 59.81
If you have system which gives another format of data, I can try adapt my software for this format.
Demo and ideal data examples you can get from this link.
Demo data are fake. They are not data of any real loudspeakers.
Simulators Practice