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Discussion Starter · #1 ·
I am attempting to model my full system (i.e sub/ mid bass/ mid range/ tweeter) to align the phase based on crossover points of each driver to get a baseline before tuning. That said, I have found no discussion on the difference between the System Overall Transfer Function Phase graph and the Filter/Equalizer Transfer Function Phase graph. They both move when adjusting crossover points, just need to know which one I should be using and your reasoning behind one vs. the other would be appreciated.

Thanks!
 

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Xsim or VirtuixCAD are normally used for that I think but those are also I think assuming you've installed on the same baffle for general loudspeaker design. I've seen a few tutorials but haven't dived in. Both are free so you could give them a try.
 

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I am attempting to model my full system (i.e sub/ mid bass/ mid range/ tweeter) to align the phase based on crossover points of each driver to get a baseline before tuning. That said, I have found no discussion on the difference between the System Overall Transfer Function Phase graph and the Filter/Equalizer Transfer Function Phase graph. They both move when adjusting crossover points, just need to know which one I should be using and your reasoning behind one vs. the other would be appreciated.

Thanks!
The filter transfer function graph is only the filters, no speaker response included.
 

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What your effectively trying to is admirable, however it’s very much pointless, once you’ve added the cars influence you can then pretty much forget the response you’d planned on paper, trust me, I use smaart and trying to get drivers to blend, match the opposite side driver and generally behave themselves... pain in the ass! 😔
 

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Discussion Starter · #5 ·
What your effectively trying to is admirable, however it’s very much pointless, once you’ve added the cars influence you can then pretty much forget the response you’d planned on paper, trust me, I use smaart and trying to get drivers to blend, match the opposite side driver and generally behave themselves... pain in the ass! 😔
The filter transfer function graph is only the filters, no speaker response included.
Interesting, so is this graph pretty much pointless? Aligning the phase under this graph is a lot easier to model. Trying to align them under the System phase graph is a mess.
 

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Discussion Starter · #6 ·
What your effectively trying to is admirable, however it’s very much pointless, once you’ve added the cars influence you can then pretty much forget the response you’d planned on paper, trust me, I use smaart and trying to get drivers to blend, match the opposite side driver and generally behave themselves... pain in the ass! 😔
Yea, that's what I figured. Just attempting to get a ballpark for the initial and wanted to make sure I am looking at the right graph (huge difference in the two phase wise). For example, from the models it looks like I need to cross the sub about a half-octave below the mid-bass for phase. It looks like the mid-range is going to be 150-220 deg out of phase with the mid-bass depending on crossover freq, so getting it close to 180 out of phase in the model and and then flip it in the DSP. I want to better understand phase relationships through the models and then see where things shake out when tuning. I attempted my first initial tune and wasn't happy with it, so going back to the drawing board to try and dial it in a little better. First time doing a full system, all my other systems just had some bass in the back so there is a learning curve 🤟.
 

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Interesting, so is this graph pretty much pointless? Aligning the phase under this graph is a lot easier to model. Trying to align them under the System phase graph is a mess.
Yeah, it is pointless. And modeling this stuff is pointless, except to see how much of a gap or overlap you MIGHT need between subs and midbass. As has already been mentioned, the responses change significantly once things are installed.
 

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Yea, that's what I figured. Just attempting to get a ballpark for the initial and wanted to make sure I am looking at the right graph (huge difference in the two phase wise). For example, from the models it looks like I need to cross the sub about a half-octave below the mid-bass for phase. It looks like the mid-range is going to be 150-220 deg out of phase with the mid-bass depending on crossover freq, so getting it close to 180 out of phase in the model and and then flip it in the DSP. I want to better understand phase relationships through the models and then see where things shake out when tuning. I attempted my first initial tune and wasn't happy with it, so going back to the drawing board to try and dial it in a little better. First time doing a full system, all my other systems just had some bass in the back so there is a learning curve 🤟.
Unfortunately this is even pointless, you can’t set phase and delays by simple maths, you could do it if you had a year... but even then you’d put it in the car and it would likely be slightly different... but it’s far easier to set a mic up in the car and measure phase and set it... delays are one thing that (although I trust a tape measure for measuring distance) the mic is way more accurate and the tape doesn’t take the phase characteristics of the sub, car or the environment into account

you can’t do what your doing and it be accurate, it will never happen sorry, put simply you are wasting your time with simple maths on a complex equation sadly

it’s like saying I want a calculator to work out why gravity doesn’t effect something
 

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Discussion Starter · #9 ·
@ckirocz28 @dumdum appreciate the feedback. I am using REW and the UMIK-1 for actual tuning, but am just getting my feet wet with it. You're right though, I need to just get back in the truck and start over with the mic. The DSP software also offers LR2 crossovers which I can't model anyways in WinISD. I will just have to watch some tutorials on phase using REW as I just have got the RTA measuring portion figured out. Time to learn a new trick. :) Thanks again!
 

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You can use the measure both drivers and use summation to workout the time alignment and phase is correct... but that only means you are in phase at the crossover and not nesc either side 👍🏼 Time alignment and phase are both linked
 
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