Hello all, I am new to the speaker building community and would like to say, thank you to all who have written and shared information. I have been reading for several months now and appreciate what I have learned.
I downloaded XSim, mainly to use the series notch filter tool, as X Over Pro does not show the effects of a notch filter in their frequency response. I downloaded the frd and zma files for 2 Dayton drivers, woofer and tweeter. I inserted the exact same 4th order crossover components with identical values into both X Sim and crossover Pro. Crossover Pro shows a net plot line jagged across the frequency range from 50 to 20000 Hertz, and running positive over the crossover points. Plus or minus for DB. X Sim has almost and identical line with the exception of it dropping 6db over the crossover points. So basically one is a half moon positive plot line through the crossover point and the other is a half moon negative. My question is, how can they be so completely opposite through this region?
Has anyone ever used either of these programs built the speakers and then measured the results? If so can you let me know how close the model was from the program versus the measurements taken after being built?
Thank you for reading and thank you in advance for any information you can provide. ML
I downloaded XSim, mainly to use the series notch filter tool, as X Over Pro does not show the effects of a notch filter in their frequency response. I downloaded the frd and zma files for 2 Dayton drivers, woofer and tweeter. I inserted the exact same 4th order crossover components with identical values into both X Sim and crossover Pro. Crossover Pro shows a net plot line jagged across the frequency range from 50 to 20000 Hertz, and running positive over the crossover points. Plus or minus for DB. X Sim has almost and identical line with the exception of it dropping 6db over the crossover points. So basically one is a half moon positive plot line through the crossover point and the other is a half moon negative. My question is, how can they be so completely opposite through this region?
Has anyone ever used either of these programs built the speakers and then measured the results? If so can you let me know how close the model was from the program versus the measurements taken after being built?
Thank you for reading and thank you in advance for any information you can provide. ML
Thank you, Erik and B-force for your response. I went back to it today and reversed polarity on the tweeter in XSim and the plots match. Hmmm I was under the impression that the tweeter and woofer should be correct with a 4th order. Am I mistaken???
Also, Has anyone ever used either of these programs built the speakers and then measured the results? If so can you let me know how close the model was from the program versus the measurements taken after being built?
Thank you for reading and thank you in advance for any information you can provide. ML
Also, Has anyone ever used either of these programs built the speakers and then measured the results? If so can you let me know how close the model was from the program versus the measurements taken after being built?
Thank you for reading and thank you in advance for any information you can provide. ML
Generally programs do not calculate wrong, though X Over Pro is unknown for me, commercial and looks quite obsolete by release date. Usually measurement data is bad or somehow incompatible with the program, or user enters parameters which are not compatible with the data or mechanics or goal of the project.
In this case we (others) would need to know what Dayton drivers you were using and what parameters entered for scaling, timing and phase response processing (phase source). That way we could evaluate your test e.g. with XSim and VituixCAD. Correct mathematical result with correct (user) parameters and valid data is guaranteed with those two. Accuracy of measurement data you load to simulator is totally different story.
About polarity of 4th order. Phase responses match with electrical 4th order L-R without inversion if acoustical magnitude and phase responses of both drivers are ideal/flat. In real life they are not, and phase mismatch or even polarity inversion is expected. You have quite a few options to match phases if that is your goal in the project. For example:
a) Equalize acoustical responses close to ideal 4th order L-R and align acoustical centers at X/O frequency. You may need e.g. electrical 2nd or 3rd order slopes to get acoustically 4th order.
b) Use electrical 4th order filters and match phase responses with all-pass filter(s) or active/dsp delay for the tweeter.
In this case we (others) would need to know what Dayton drivers you were using and what parameters entered for scaling, timing and phase response processing (phase source). That way we could evaluate your test e.g. with XSim and VituixCAD. Correct mathematical result with correct (user) parameters and valid data is guaranteed with those two. Accuracy of measurement data you load to simulator is totally different story.
About polarity of 4th order. Phase responses match with electrical 4th order L-R without inversion if acoustical magnitude and phase responses of both drivers are ideal/flat. In real life they are not, and phase mismatch or even polarity inversion is expected. You have quite a few options to match phases if that is your goal in the project. For example:
a) Equalize acoustical responses close to ideal 4th order L-R and align acoustical centers at X/O frequency. You may need e.g. electrical 2nd or 3rd order slopes to get acoustically 4th order.
b) Use electrical 4th order filters and match phase responses with all-pass filter(s) or active/dsp delay for the tweeter.
Kimmosto,
Thank you for the detailed and excellent response. I will have to look up some of what you said, to better understand in full detail. Noob here. As for measuring, that will come sometime down the road for me. Hopefully a month or 2, then I will know how accurate the programs are. Seems like the XSim will be the better of the 2 at this point.
ML
Thank you for the detailed and excellent response. I will have to look up some of what you said, to better understand in full detail. Noob here. As for measuring, that will come sometime down the road for me. Hopefully a month or 2, then I will know how accurate the programs are. Seems like the XSim will be the better of the 2 at this point.
ML
Accuracy of system calculation and transfer functions can be tested with ideal (generated) measurement data. Typically error in total SPL and impedance calculation is insignificant; decade(s) smaller than errors in measurements and component tolerances. Components in simulated network are usually ideal, and reality has lots of imperfections; non-linearities, noise etc. So, "how accurate the programs are" is kind of wrong question.
That is quite difficult to believe. At least I don't expect that X Over Pro would have parameters for non-linearities -> both programs use equal; ideal crossover components -> no differences in simulation without clear bug or wrong use. You will probably see just repeatability of your measurements and gear including noise of environment and differences due to impedance measurement setup (signal, source impedance) etc.
Everything else in measurement and design process is decades more relevant and important than accuracy of crossover simulator.
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