VituixCAD

Something else: I want to be able to compare the directivity graph style "Surface chart" to the ones that JA from stereophile does with MLSSA in his reviews. Just to compare projected performance in this style of representation.
Would you know how this can be done? JA uses 25 dB SPL of vertical and +-90 degree of lateral information and nomalizes for on-axis. In VCD I can set the scale to 25 dB and normalize, but it looks very different to MLSSAs charts because the vertical scale is much more extended. any solution or workaround?
 
^The latest build (2.0.72.2) can do this though I don't see much sense to use Stereophile's directivity measurements as a reference.
P.S. VituixCAD discussion on HTguide.
 

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Questions about driver database from Vituixcad

Hello Kimmo
A few questions about the great driver database that comes with Vituix:
1. Where did this data come from? How accurate is it and does it get updated somehow? I’m curious how you were able to create such a large list!

2. I’m interested to add more parameters to my local database .txt file for my own use (not needed by the program), for example, diameter and depth dimensions of the driver, maybe some coefficients from Klippel, Cost, etc. is it possible to allow users to add Unlimited extra columns into the file without corrupting the functions of Vituixcad?

Thanks!
 
^The latest build (2.0.72.2) can do this though I don't see much sense to use Stereophile's directivity measurements as a reference.
P.S. VituixCAD discussion on HTguide.
Hello Kimmo,
1) Stereophile's graphs provide a huge set of comparable directivity performance for many different speakers, making it easier to compare one's own design, given the representations are comparable. I find it easier if I see the same representation and shortcut the mental translation step.
2) I find these MLSSA charts quite intuitive, regardless of the fact if I would agree on the usability of the chosen limits. They are easier to follow than line charts or sonograms and to identify weaknesses, because the deviation is shown in third dimension. It would even be better if further scaling/a scale/a grid was visualy available, but that is too much to ask for.
3) Thanks for the invitation to HTguide, I will certainly follow soon to discuss your very good software.
Thanks for everything.
 
1. Where did this data come from? How accurate is it and does it get updated somehow?

Many sources. Imported from LspCAD 5.25, AJHorn and manufactures' datasheets with pdf reader, entered manually by me and 1-2 others, few drivers copy-pasted from loudspeakerdatabase.com.

Simulation with T/S-model is simplification. Accuracy depends on many things. Purpose is to help and speed up product selection and calculation of enclosure volume and dimensions of possible vent(s). Not possible to get exact match with reality, and fortunately that's not required because significance of radiator simulation is very low in design process.

I could update online data, but why would I do everything alone. Users have had very close to zero interest to send data for online database. Everyone plays own game.

2. I’m interested to add more parameters to my local database .txt file for my own use (not needed by the program), for example, diameter and depth dimensions of the driver, maybe some coefficients from Klippel, Cost, etc. is it possible to allow users to add Unlimited extra columns into the file without corrupting the functions of Vituixcad?

Not surprised. You want that I work few weeks and add new features to program that also you could maintain own data and play own game.
I could add some fixed fields. Custom fields probably require changing file format or using some actual database or at least limiting clipboard format to xml or json to maintain possibility to copy paste from other driver databases.

Sorry about frustration. I'm also trying to stay on HTguide only so write there get answers faster.
 
Can someone give me a rundown on what the correct and accepted procedure when simulating diffraction and baffle step for nearfield measurements?

I mean, I take nearfield of the woofer and port, then calculate diffraction for each of them before summing them , or do I sum first after adjusting port gain vs cone area, and then only apply diffraction based on the woofer ? Also in the diffraction tool, if i take my far field measurements with the mic on tweeter axis for all drivers, and use time lock to avoid dealing with offsets and so forth, should the mic position in the diffraction tool be aswell be positioned on the assumed tweeter axis, or should it be centered on the woofer regardless of the axis I take farfield measurements on?
 
I don't bother measuring the port for purpose of crossover design, it doesn't affect crossover operation at >1kHz, but if you want to include it the process would be to merge it with the nearfield driver measurement, then apply diffraction, then splice with far field measurement.

Mic position for diffraction simulation should be the location of your mic when you took the far field measurement. This should be obvious, as the intent is to fill in missing data in the gated far field measurement.

If you want to design using full 360 degrees spinorama of response, drivers should be measured on their own axis, not the tweeter. In fact with any 2 channel measurement even if you are using single axis data I would still measure at the driver's axis, and include the driver seperation on the baffle in the crossover design.
 
tip: measure port response at some point of the design process! Mids leaking through the port can be bad enough to ruin the speaker.
See attached measurement, found on Volti Audio Rival loudspeaker Measurements | Stereophile.com . The red response is from the port. Standing wave in the enclosure at ~160Hz comes through as loud as the Helmholtz resonance, couldn't be worse. I wonder if this was someones first speaker and didn't see the resonance, or forgot to do measurements.. :D
 

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I've been using Basta so far and a friend suggested to try VituixCAD. I assume its possible but I couldn't find a way to model an Open Baffle enclosure. I can see an Open Baffle option under Diffraction but not under Enclosure. I'd appreciate if someone can provide the exact steps. As a simple example what would be the steps to model a FAST with a full range and a woofer on a flat baffle of say 60"x24"?
 
I've been using Basta so far and a friend suggested to try VituixCAD. I assume its possible but I couldn't find a way to model an Open Baffle enclosure. I can see an Open Baffle option under Diffraction but not under Enclosure. I'd appreciate if someone can provide the exact steps. As a simple example what would be the steps to model a FAST with a full range and a woofer on a flat baffle of say 60"x24"?

look at post 2231 to see how to model a dipole

https://www.diyaudio.com/forums/software-tools/307910-vituixcad-224.html#post6277316
 
Not in a hurry...

I thought since the Enclosure doesn't have Open Baffle option I have to skip it. Also, seemed like Crossover was the only place to specify a dipole. So here is what I have so far.

I haven't put in the X and Y as yet. If I understand it correctly, 0,0 would be on-axis with the listening position. Looking at the driver -ve X would mean to the left, +ve to right, -ve Y would be down and +ve is up?

Also how do I now enter stuff into the Enclosure? I'm finding the manual a bit difficult to follow.
 

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you are missing a ground return on the back side driver model

You are right re enclosure tool. There is no explicit menu selection for OB. I think closed box with really large box volume might get you close in terms of excursion but there is more to it than that and I'm not sure how that all plays out.
 
I did think of that but won't that model an Infinite Baffle and not an Open Baffle? Because the box will be very large (like mounting the speaker in the wall) but will prevent the front and back from interfering which need for Open Baffle.

Cabinet models don't include baffle effects, they are nearfield simulations. With that in mind, there is not a difference as far as driver excursion is concerned, both situations there is nothing "pushing back" against the driver, it operates in free air. The enclosure response will reflect what you would measure as a near field response. You can export the enclosure response and bring it into the diffraction simulator to include the baffle effects. This sort of simulation is not good enough for filter design however, only good for insight into the low frequency operation of the driver on the baffle. You can also go the other way around, simulate the diffraction response and bring it into the enclosure model, you will see the option under the "align" tab in the enclosure model.

Recommended process is to design with real measurements. Process for measuring open baffle speaker is not different than any other. Follow the guide for measurement process with ARTA or REW.
 
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