Main folder includes impedance files and distortion measurements at 96db @ 315mm (equivalent to 86db at 1m). That $15 tweeter's distortion is pretty impressive. The Fs measured 1,225Hz.
Farfield includes on- and off-axis measurements of tweeter and woofer at 1m, horizontal and vertical, 0 to 180 degrees in 10 degree increments. You don't need the farfield woofer measurements unless you want to practice merging them yourself (see note below).
Nearfield includes nearfield of woofer and port
Merged is the woofer farfield measurements merged with the nearfield
Note, you do not need to do anything with the nearfield measurements if you don't want. You can use the tweeter files in the Farfield folder and the woofer files in the Merged folder and be good to go. I will post later some notes on the merge process and you can play around with merging them yourself if you want, but you don't have to. (See the VituixCAD Measurement REW help file at the top of THIS PAGE for the merge process.)
If you have questions about getting the data into VituixCAD or starting your simulations, just post here and I'm sure you will get a lot of help.
If anyone else wants to simulate a design, feel free to use the data in the zip file in your preferred software.
I'm playing along and have put together a tentative Vcad model. In a previous post, the C-t-C spacing distance between tweeter and woofer was specified as 6.5" (or 165mm). But I also noticed that the cabinet dimensions had also changed since this post, so maybe the C-t-C spacing distance was modified as well. I'm using -165mm for my woofer Y offset. Would this be correct? I'll hold off posting additional details of my schematic for a couple days weeks, as this will give others a chance to independently develop better (or different) ideas.
While I'm working out how to use Vituix, I just put the on-axis data into Xsim and did a very (very) quick exercise.
Apologies for all the blank space:
It was interesting to compare the differences between the in-box measured data, that provided by PE for the woofer and my efforts with fptrace for the Vifa.
While it looks not to be the most efficient speaker, this combo should sound nice.
@GeoffMillar said:
While I'm working out how to use Vituix, I just put the on-axis data into Xsim and did a very (very) quick exercise.
VituixCAD doesn't disagree (see the six pack below). BUT...I'd recommend zooming in more, say a max SPL of 10dB more than your target and a minimum 30-40dB less than your target. (I like to use 40dB below so that I can see if certain things (like cone breakup of an aluminum woofer) are down that far.) See the zoomed in image below and you can see that the "hump" between 550Hz and 1kHz is more pronounced than it appears in your smoother xsim graph.
Thanks for that: perhaps some more parts are needed to deal with that hump, it's in a rather nasty place. I tried a higher value inductor but that just pushed the output down some more.
Please excuse the stupid question, but how to you target a particular SPL?
What I'm seeing is not enough BSC applied because the woofer is still rising to te xover point. It should be tilted far enough down that the response flattens out. Then deal with the bump before rolloff. I would suggest a resistor in line with the woofer parallel capacitor, as this can damp the knee and reduce its magnitude. 1-2 ohms to start for a ballpark. If this and a cap adjustment are not able to smooth this out, you have some more options:
You can go third order with another lowpass coil, and tweak. (My bet is third order and added shunt resistor should do it.)
you can add a parallel notch placed in series with the woofer to suppress it.
you can add a series notch in parallel with the woofer to suppress it, watch your impedance.
Usually one of these above will get it done.
I also bet a small 0.22 cap across the large lowpass coil will further tank the breakup and suppress it more.
@GeoffMillar said:
Thanks for that: perhaps some more parts are needed to deal with that hump, it's in a rather nasty place. I tried a higher value inductor but that just pushed the output down some more.
I was pretty impressed with your first "very (very) quick exercise". I spent some time playing with it last night, and I'll tell you some things I did (I think I'm on xo variant 13 right now LOL). I tried to get as good a response as I could get, no constraints. I started with 4th order electrical and notch filters and removed things if they weren't needed; I ended up with 3rd order electrical on both and a series notch filter on the woofer with an 8mH inductor to flatten out that hump (13 total components). Then I tried to remove components and see if I could maintain roughly the same response with fewer parts. That is still where I am currently at - I may actually wire up a crossover and measure tonight to see (1) how closely is it matching the sim and (2) with a xo in place, is that hump at 650hz (without the expensive notch filter in place) as prominent as the sim suggests.
Please excuse the stupid question, but how to you target a particular SPL?
In VituixCAD, as 'm trying to see if I can use it, but in general also please.
With my very basic level of knowledge about these things, I thought that woofer X would measure say, 87dB according to the maker, then you put it in a cabinet and add moderate BSC, then you might get, say, 83dB?
You could reduce the woofer output, by adding more BSC but you can't increase the output, so is the 'target' the efficiency level you'd like to achieve from the speaker?
Is the 8mH a sub for the 2.5mH please? It's a very large value and would blow the budget even if I used an i-core....
Wolf, thank you for your small cap suggestion - I've modelled it and it improves things.
@GeoffMillar said:
In VituixCAD, as 'm trying to see if I can use it, but in general also please.
With my very basic level of knowledge about these things, I thought that woofer X would measure say, 87dB according to the maker, then you put it in a cabinet and add moderate BSC, then you might get, say, 83dB?
You could reduce the woofer output, by adding more BSC but you can't increase the output, so is the 'target' the efficiency level you'd like to achieve from the speaker?
Let me start with, I'm relatively new compared to Ben and many others here, so hopefully someone will correct me if I am wrong.
Your basic starting point seems right. And sometimes it is pretty straight forward, your woofer measurement will clearly show where SPL is falling due to baffle step loss so you determine the target SPL based on that and figure out what size inductor to use (or maybe a proper "BSC" circuit, although I hardly ever see that) and then bring the tweeter down to that level. In this case, I found it a little challenging to figure out the target level, and you won't REALLY know until you wire something up and try it. My last speaker I thought I had things dialed in pretty good, wired up my first xo and played a few test tracks and was surprised that I had very thin bass. For your speaker, I am currently targeting about 79dB and am using a 2.5mH inductor, which is where I think you are at also. (By the way, the SPL in the measurements is not 100% accurate, we are probably really looking at 81dB but your earlier comment about it being low sensitivity is correct.)
Is the 8mH a sub for the 2.5mH please? It's a very large value and would blow the budget even if I used an i-core....
Yes, the 8mH inductor was in a series notch with a 7.5uF capacitor and 22ohm resistor - separate from the 2.5mH inductor. I am not suggesting you actually implement this (expensive) crossover, but rather (1) I struggled with that bump at 650Hz and wanted you to know it is not an easy fix, so you wouldn't think you were just missing some obvious solution; and (2) you can put something like it in place as a reference of what it "could" look like and you can remove it and see how close you can get using a combination of other components. In my opinion, it "looks" bad, but realistically it is about 1-1.5Hz bump from 550Hz to 850hz (in my sim right now) and not worth the price of an RS180 to get rid of it.
You can set targets in the "Optimizer" (right click in any of the panes, it is the first item).
Optimizer feature: You can set all kinds of targets and IF you want you can click the "Optimize" button and VituixCAD will iterate changes in components to get close to your target. In the xo pane you can right click to select components to Optimize (or select them all and then right click). I don't try to get a "solution" using the optimizer, but it can come in really hand to get "close" in certain cases. For example, you can set a target for a LR4 low-pass on the woofer, but keep the 2.5mH inductor turned "off" since you know that is giving you the BSC that you want and VituixCAD doesn't know that.
Setting targets: To show your targets, right-click in the pane and select "Show Target curve". You probably don't need to, because one thing I find annoying is that even though I turn this OFF, every time I change something it defaults back to showing targets. You can also right click and select "Traces" and show/hide certain curves, as well as change the colors and line width. I don't love the light gray for the On-axis curve so I often change it to Gold and may make it thicker.
You can set "Ref axis response of Speaker" with a target SPL level and this will give you a flat target. You can also add a "tilt" to it if desired. (In the "Textbook target" section).
You can set the "Ref axis response of Driver" and select the tweeter or woofer in the drop down box. Then go over to the "Textbook target" section and set your low-pass or high-pass to Butterworth, LR, 2nd order, 3rd order, target SPL, etc. My first variants are usually setting LR4 targets at a xo point that I know is likely to be close due to either the size of the woofer or knowing that a tweeter shouldn't go lower than some point. Another annoying thing is that VituixCAD will almost always change the target from "Ref axis response of Driver" if I change anything, so I have to re-select the driver I am working with.
If you target "Listening window" it will be paired with either "Sound Power" or "Predicted In-room" (PIR) and you have to select the weights. I just leave them at 50%/50%. If you change the SPL target and tilt in the "Textbook target" section it defaults to the Listening window. To target the Sound Power or PIR you have to select the "Seek level" or "modify target" radio button and then the Textbook target section applies to those.
I have found this suggested target very useful:
Listening window and in-room response at 50/50 weight. Set listening window target slope at -0.15dB/oct from 100Hz to 10kHz. Set PIR response target slope at about -0.8 to -1dB from ~300Hz to 10kHz depending on the speaker.
Below is the first thing I would have started with yesterday. Here is an LR4 low-pass target for 2.5kHz at 79.5dB. After much playing around, I would have got something reasonable, then moved on to an LR4 high-pass on the tweeter. Then I would have tried different crossover points and orders. At some point, I'm done targeting specific acoustic slopes on individual drivers and am looking at the overall SPL response, or cone break up or PIR, etc.
One other useful thing. You can save up to 8 crossover variants. So, I worked through 8 variants and saved the file "Geoff M v1", worked through 8 more and saved "Geoff M v2" and am now working in the version 3 file.
Sometimes I am trying to achieve a certain goal but forget what the heck the differences between variant 2 and 6 were, and what I was even thinking at the time. There is a button up at the top, just a box with a "T" that allows you to add text. So, for example, I have created crossovers with 2.0mH, 2.2mH, 2.5mH and 3.0mH inductors on the woofer. On my large monitor, the text indicating the mH on the inductors is quite small so it is not obvious what the difference between variants is, so I have added a text box in a large font and bold what inductor I was experimenting with. Sometimes I get to a nice total SPL curve, but I know my phase is not very good. So I add a text box "Working on Phase" to remind myself what it was I was trying to achieve in that variant. Another example "LR4 @2500" or "LR3 @2600" to remind myself of the targets I was working on, since 4 days from now I'm not going to remember.
It's been a couple days, so I'll post my best Vituix "6 pack," so far. I used most of Wolf's suggestions above. I listed my targets so you can kind of see what I was trying to do. Xover is approx 2.5kHz with 11 parts. Woofer inductor is 3.9mH with up to 1 ohm of DCR, so either an iron or air core should work. (PE #257-842 18ga air core 4mH or PE #257-662 iron core would work). This big inductor, as other's have noted above, serves to pull down that nasty 500Hz to 1.5kHz BSC related bump up problem. This xover version gets a very high preference rating. I don't know if that really means anything, but I have found that when you get the very best compromise between on and off axis curves, the preference score always goes up. Just how important this actually is, I do not know. I view it as a useful tool that helps me to get where I am going. I'll keep working on it and watching to see what others come up with.
@a4eaudio said:
I have found this suggested target very useful:
Listening window and in-room response at 50/50 weight. Set listening window target slope at -0.15dB/oct from 100Hz to 10kHz. Set PIR response target slope at about -0.8 to -1dB from ~300Hz to 10kHz depending on the speaker.
That guy gave you good advice . Slope will ultimately be defined by the drivers used, but above is a good starting point for optimization.
Be careful of the fairly shallow rolloff of the tweeter. It still has significant output to 1.5kHz which is likely to bring out it's "cheap" qualities.
It's important to set start and end frequencies for optimization. Start freq for on-axis shown at 77dB and 25Hz sets an unobtainable goal when actual output is 40dB at this frequency. For overall response goals, I generally limit the frequency range from 100-200Hz to 15000Hz.
Other tips:
Optimizer is an iterative component adjustment process, not a design-o-matic. It simply adjusts component values and calculates an error between the target curve and actual response. It works best when the response is already in the ballpark of your target with expected crossover frequency. An optimizer looking at on-axis and power response is not looking at your crossover frequencies or slope or notch filters, so choose topology wisely first, and limit optimizer to target only the components you want to adjust.
ctrl-click on left and right side of the SPL and CTA-2034 chart to quickly set target response start/end frequency and slope.
I played along. It's good that you've provided some separation between midwoofer and tweeter rather than trying to cram them together. I won't share the schematic, because I think Geoff should build a speaker of his design, not mine. It's possible to get a better response than what I show below, but the balance here includes consideration of the distortion characteristics of the drivers.
Thank you all for your comments and suggestions, I'll have a play over the next few days and see what I can come up with.
Am still trying to get to terms with Vituix.....reminds me of the old Groucho Marx joke: "a four year old child could understand this, go and bring me a four year old child".
@4thtry said:
It's been a couple days, so I'll post my best Vituix "6 pack," so far. I used most of Wolf's suggestions above. I listed my targets so you can kind of see what I was trying to do. Xover is approx 2.5kHz with 11 parts.
Thank you for that: a stupid question if I may: when I put those XO values into Xsim, I get a XO point of 1600Hz?
I know I should be using Vituix but am still trying to learn it.
Interesting. Give me a few minutes. I'll enter my xover values in XSim and test to see if I can duplicate your results. I don't have Z offset data for for setting up the XSim model, but that small amount of phase rotation error should not have a major inpact on the on-axis model.
Here is what I get when entering the on-axis frd's and zma's in XSim. Almost identical to my Vcad model. The XSim model needs a small amount of Z offset (mod delay) applied to the tweeter for a exact match, but this small amount of phase error is almost impossible to detect. Could you post a screen shot of your woofer and tweeter driver tuning icons in XSim?
Comments
@GeoffMillar,
See attached zip file for measurements:
Note, you do not need to do anything with the nearfield measurements if you don't want. You can use the tweeter files in the Farfield folder and the woofer files in the Merged folder and be good to go. I will post later some notes on the merge process and you can play around with merging them yourself if you want, but you don't have to. (See the VituixCAD Measurement REW help file at the top of THIS PAGE for the merge process.)
If you have questions about getting the data into VituixCAD or starting your simulations, just post here and I'm sure you will get a lot of help.
If anyone else wants to simulate a design, feel free to use the data in the zip file in your preferred software.
Many, many thanks for going to so much trouble.
Looking forward to simming and crossover-ing!
Cheers
Geoff
I'm playing along and have put together a tentative Vcad model. In a previous post, the C-t-C spacing distance between tweeter and woofer was specified as 6.5" (or 165mm). But I also noticed that the cabinet dimensions had also changed since this post, so maybe the C-t-C spacing distance was modified as well. I'm using -165mm for my woofer Y offset. Would this be correct? I'll hold off posting additional details of my schematic for a couple days weeks, as this will give others a chance to independently develop better (or different) ideas.
Yes, 165mm is correct.
I have also played around with the data but will wait awhile to post.
Test Bench: Dayton Audio RS180P-8 7” Reference Series Midwoofer
https://audioxpress.com/article/test-bench-dayton-audio-rs180p-8-7-reference-series-midwoofer
While I'm working out how to use Vituix, I just put the on-axis data into Xsim and did a very (very) quick exercise.
Apologies for all the blank space:
It was interesting to compare the differences between the in-box measured data, that provided by PE for the woofer and my efforts with fptrace for the Vifa.
While it looks not to be the most efficient speaker, this combo should sound nice.
Work in progress!
Geoff
>
Geoff
Those don't look "too" different from what I posted on the first page.
[Edit: Posted at the same time as Geoff]
VituixCAD doesn't disagree (see the six pack below). BUT...I'd recommend zooming in more, say a max SPL of 10dB more than your target and a minimum 30-40dB less than your target. (I like to use 40dB below so that I can see if certain things (like cone breakup of an aluminum woofer) are down that far.) See the zoomed in image below and you can see that the "hump" between 550Hz and 1kHz is more pronounced than it appears in your smoother xsim graph.
Thanks for that: perhaps some more parts are needed to deal with that hump, it's in a rather nasty place. I tried a higher value inductor but that just pushed the output down some more.
Please excuse the stupid question, but how to you target a particular SPL?
Thank you and apologies for the newbie question
Geoff
What I'm seeing is not enough BSC applied because the woofer is still rising to te xover point. It should be tilted far enough down that the response flattens out. Then deal with the bump before rolloff. I would suggest a resistor in line with the woofer parallel capacitor, as this can damp the knee and reduce its magnitude. 1-2 ohms to start for a ballpark. If this and a cap adjustment are not able to smooth this out, you have some more options:
Usually one of these above will get it done.
I also bet a small 0.22 cap across the large lowpass coil will further tank the breakup and suppress it more.
InDIYana Event Website
I was pretty impressed with your first "very (very) quick exercise". I spent some time playing with it last night, and I'll tell you some things I did (I think I'm on xo variant 13 right now LOL). I tried to get as good a response as I could get, no constraints. I started with 4th order electrical and notch filters and removed things if they weren't needed; I ended up with 3rd order electrical on both and a series notch filter on the woofer with an 8mH inductor to flatten out that hump (13 total components). Then I tried to remove components and see if I could maintain roughly the same response with fewer parts. That is still where I am currently at - I may actually wire up a crossover and measure tonight to see (1) how closely is it matching the sim and (2) with a xo in place, is that hump at 650hz (without the expensive notch filter in place) as prominent as the sim suggests.
Do you mean in general or in VituixCAD?
In VituixCAD, as 'm trying to see if I can use it, but in general also please.
With my very basic level of knowledge about these things, I thought that woofer X would measure say, 87dB according to the maker, then you put it in a cabinet and add moderate BSC, then you might get, say, 83dB?
You could reduce the woofer output, by adding more BSC but you can't increase the output, so is the 'target' the efficiency level you'd like to achieve from the speaker?
Is the 8mH a sub for the 2.5mH please? It's a very large value and would blow the budget even if I used an i-core....
Wolf, thank you for your small cap suggestion - I've modelled it and it improves things.
Cheers
Geoff
Let me start with, I'm relatively new compared to Ben and many others here, so hopefully someone will correct me if I am wrong.
Your basic starting point seems right. And sometimes it is pretty straight forward, your woofer measurement will clearly show where SPL is falling due to baffle step loss so you determine the target SPL based on that and figure out what size inductor to use (or maybe a proper "BSC" circuit, although I hardly ever see that) and then bring the tweeter down to that level. In this case, I found it a little challenging to figure out the target level, and you won't REALLY know until you wire something up and try it. My last speaker I thought I had things dialed in pretty good, wired up my first xo and played a few test tracks and was surprised that I had very thin bass. For your speaker, I am currently targeting about 79dB and am using a 2.5mH inductor, which is where I think you are at also. (By the way, the SPL in the measurements is not 100% accurate, we are probably really looking at 81dB but your earlier comment about it being low sensitivity is correct.)
Yes, the 8mH inductor was in a series notch with a 7.5uF capacitor and 22ohm resistor - separate from the 2.5mH inductor. I am not suggesting you actually implement this (expensive) crossover, but rather (1) I struggled with that bump at 650Hz and wanted you to know it is not an easy fix, so you wouldn't think you were just missing some obvious solution; and (2) you can put something like it in place as a reference of what it "could" look like and you can remove it and see how close you can get using a combination of other components. In my opinion, it "looks" bad, but realistically it is about 1-1.5Hz bump from 550Hz to 850hz (in my sim right now) and not worth the price of an RS180 to get rid of it.
Post to follow regarding targets in VituixCAD...
Thank you!
Geoff
You can set targets in the "Optimizer" (right click in any of the panes, it is the first item).
Optimizer feature: You can set all kinds of targets and IF you want you can click the "Optimize" button and VituixCAD will iterate changes in components to get close to your target. In the xo pane you can right click to select components to Optimize (or select them all and then right click). I don't try to get a "solution" using the optimizer, but it can come in really hand to get "close" in certain cases. For example, you can set a target for a LR4 low-pass on the woofer, but keep the 2.5mH inductor turned "off" since you know that is giving you the BSC that you want and VituixCAD doesn't know that.
Setting targets: To show your targets, right-click in the pane and select "Show Target curve". You probably don't need to, because one thing I find annoying is that even though I turn this OFF, every time I change something it defaults back to showing targets. You can also right click and select "Traces" and show/hide certain curves, as well as change the colors and line width. I don't love the light gray for the On-axis curve so I often change it to Gold and may make it thicker.
You can set "Ref axis response of Speaker" with a target SPL level and this will give you a flat target. You can also add a "tilt" to it if desired. (In the "Textbook target" section).
You can set the "Ref axis response of Driver" and select the tweeter or woofer in the drop down box. Then go over to the "Textbook target" section and set your low-pass or high-pass to Butterworth, LR, 2nd order, 3rd order, target SPL, etc. My first variants are usually setting LR4 targets at a xo point that I know is likely to be close due to either the size of the woofer or knowing that a tweeter shouldn't go lower than some point. Another annoying thing is that VituixCAD will almost always change the target from "Ref axis response of Driver" if I change anything, so I have to re-select the driver I am working with.
If you target "Listening window" it will be paired with either "Sound Power" or "Predicted In-room" (PIR) and you have to select the weights. I just leave them at 50%/50%. If you change the SPL target and tilt in the "Textbook target" section it defaults to the Listening window. To target the Sound Power or PIR you have to select the "Seek level" or "modify target" radio button and then the Textbook target section applies to those.
I have found this suggested target very useful:
Listening window and in-room response at 50/50 weight. Set listening window target slope at -0.15dB/oct from 100Hz to 10kHz. Set PIR response target slope at about -0.8 to -1dB from ~300Hz to 10kHz depending on the speaker.
Below is the first thing I would have started with yesterday. Here is an LR4 low-pass target for 2.5kHz at 79.5dB. After much playing around, I would have got something reasonable, then moved on to an LR4 high-pass on the tweeter. Then I would have tried different crossover points and orders. At some point, I'm done targeting specific acoustic slopes on individual drivers and am looking at the overall SPL response, or cone break up or PIR, etc.
Thanks for that, makes it much easier to understand
Geoff
One other useful thing. You can save up to 8 crossover variants. So, I worked through 8 variants and saved the file "Geoff M v1", worked through 8 more and saved "Geoff M v2" and am now working in the version 3 file.
Sometimes I am trying to achieve a certain goal but forget what the heck the differences between variant 2 and 6 were, and what I was even thinking at the time. There is a button up at the top, just a box with a "T" that allows you to add text. So, for example, I have created crossovers with 2.0mH, 2.2mH, 2.5mH and 3.0mH inductors on the woofer. On my large monitor, the text indicating the mH on the inductors is quite small so it is not obvious what the difference between variants is, so I have added a text box in a large font and bold what inductor I was experimenting with. Sometimes I get to a nice total SPL curve, but I know my phase is not very good. So I add a text box "Working on Phase" to remind myself what it was I was trying to achieve in that variant. Another example "LR4 @2500" or "LR3 @2600" to remind myself of the targets I was working on, since 4 days from now I'm not going to remember.
That's very useful; I can also lose track of where I've got to
Geoff
It's been a couple days, so I'll post my best Vituix "6 pack," so far. I used most of Wolf's suggestions above. I listed my targets so you can kind of see what I was trying to do. Xover is approx 2.5kHz with 11 parts. Woofer inductor is 3.9mH with up to 1 ohm of DCR, so either an iron or air core should work. (PE #257-842 18ga air core 4mH or PE #257-662 iron core would work). This big inductor, as other's have noted above, serves to pull down that nasty 500Hz to 1.5kHz BSC related bump up problem. This xover version gets a very high preference rating. I don't know if that really means anything, but I have found that when you get the very best compromise between on and off axis curves, the preference score always goes up. Just how important this actually is, I do not know. I view it as a useful tool that helps me to get where I am going. I'll keep working on it and watching to see what others come up with.
Bill, I really like what you did with the text feature. Not only useful, but looks very nice as well!!
A simple BSC filter often works to flatten that shit. Give it a try.
That guy gave you good advice
. Slope will ultimately be defined by the drivers used, but above is a good starting point for optimization.
Be careful of the fairly shallow rolloff of the tweeter. It still has significant output to 1.5kHz which is likely to bring out it's "cheap" qualities.
It's important to set start and end frequencies for optimization. Start freq for on-axis shown at 77dB and 25Hz sets an unobtainable goal when actual output is 40dB at this frequency. For overall response goals, I generally limit the frequency range from 100-200Hz to 15000Hz.
Other tips:
I played along. It's good that you've provided some separation between midwoofer and tweeter rather than trying to cram them together. I won't share the schematic, because I think Geoff should build a speaker of his design, not mine. It's possible to get a better response than what I show below, but the balance here includes consideration of the distortion characteristics of the drivers.
Thank you all for your comments and suggestions, I'll have a play over the next few days and see what I can come up with.
Am still trying to get to terms with Vituix.....reminds me of the old Groucho Marx joke: "a four year old child could understand this, go and bring me a four year old child".
I'm enjoying the journey!
Geoff
I know I should be using Vituix but am still trying to learn it.
Interesting. Give me a few minutes. I'll enter my xover values in XSim and test to see if I can duplicate your results. I don't have Z offset data for for setting up the XSim model, but that small amount of phase rotation error should not have a major inpact on the on-axis model.
Thank you - I'm sure there must be something strange with my efforts
Geoff
Here is what I get when entering the on-axis frd's and zma's in XSim. Almost identical to my Vcad model. The XSim model needs a small amount of Z offset (mod delay) applied to the tweeter for a exact match, but this small amount of phase error is almost impossible to detect. Could you post a screen shot of your woofer and tweeter driver tuning icons in XSim?
91nF = 0.091uF.
0.1in mod delay on the woofer in Xsim
Good catch! Geoff, this is also what VituixCAD shows with 0.91uF (what you have) versus 0.091uF (what Bill has).