VituixCAD v2

[kimmosto]

2.0.69.0 (2021-05-16)

Convert IR to FR
* Added Open session button.
* Added Save session button.

This saves also chart settings and overlays within visible range in addition to IR file list and FFT analysis and Output settings.

[kimmosto]

2.0.69.0 (2021-05-17) part II

Also properties of fixed traces in IR and FR charts are saved to FFT session file. Basically everything else expect Y max of IR chart and currently selected IR file.

[fluid]

.
More philosophical discussion; what is important, when (=what cases) and why, and what looks just overshoot in my or your opinion.

Given the above I hope the following is within bounds. You wrote at diyaudio not too long ago about a stereo cardioid speaker being a good choice. I like the idea of giving this a try and the Genelec W371 has caught my eye. I already have two drivers which seem like they could work with this concept (Faital 15FH500 and Dayton RSS390HF). I plan get started simulating this in Vituix but I wondered if you had any tips for the active cardioid simulation or any philosophical thoughts on the different cardioid patterns and which might be good to aim for and why.

[kimmosto]

^I would prefer two front woofers and two side woofers over W371 concept to get wider cardioid frequence range. Just like lower half of Kii BXT's woofer section, but e.g. with 4x12" drivers for each speaker. Internal walls between front and side woofers could leak through damping material to enable smaller volumes.

Active filter looks like this. Delay for side woofers is produced simply with extra 2nd order low-pass filter which also reduces mid-range noise to back (to be more compatible with front wave). Directivity of cones attenuate HF noise to back. Low-pass for delay can also be 2nd order passive L+C.

[nc535]

^I would prefer two front woofers and two side woofers over W371 concept to get wider cardioid frequence range. Just like lower half of Kii BXT's woofer section, but e.g. with 4x12" drivers for each speaker. Internal walls between front and side woofers could leak through damping material to enable smaller volumes.

Active filter looks like this. Delay for side woofers is produced simply with extra 2nd order low-pass filter which also reduces mid-range noise to back (to be more compatible with front wave). Directivity of cones attenuate HF noise to back. Low-pass for delay can also be 2nd order passive L+C.

That is a compelling response even if it takes 4 drivers to reproduce but I must be copying it wrong. I don't see any horizontal asymmetries but I'm getting a lopsided horizontal directivity response. Only obvious difference in the sims is the woofer directivity; mine was simulated via diffraction tool and pnly has positive angles...?

[IMG]file:///D:/Audio/Projects/Reference%20System%20Configurations/Cardiod%20Woofer%20Box/Cardiod12s%20Directivity%20(hor).png[/IMG]

[nc535]

maybe this will work for the image


(edited by administrator... I attached the image to your post, as dropbox doesn't work with hot linked images)

[fluid]

^I would prefer two front woofers and two side woofers over W371 concept to get wider cardioid frequence range.

Thanks, that is a well controlled response.

I have the Faital 15" driver to cross over to a horn above from 500 to 800Hz depending on prototype measurements. The directivity of the W371 intrigued me as it looks pretty well controlled up towards the horn crossover range but transitions back to monopole below 80Hz. This seemed like it could still be efficient at the lowest frequencies but improve room response interaction in the 200 to 500 Hz range.



What do you think is the advantage or disadvantage between this and the side woofer scheme?

Using the 4 x 12 arrangement below the 15" woofer would be nice but it is a lot of extra drivers to purchase, food for thought.

P.S. nc535 your image doesn't show

[Kevin P]

Hi nc535, I see you were having trouble with your image so I fixed it for you. For future reference, if you click "Go Advanced", then "Manage Attachments", you can upload images directly to the forum.

You can also use a site like imgur which allows hotlinking of images.

[kimmosto]

...but I must be copying it wrong.[/IMG]

Rotation R of upper side woofer D3 is +90 degrees (right) and lower side woofer D4 is -90 degrees (left).
Partial export 0...+180 deg from Diffraction tool works too. 'Mirror missing' must be on if drivers are rotated or tilted.

[kimmosto]

What do you think is the advantage or disadvantage between this and the side woofer scheme?

Both - depending on targets and priorities Full range cardioid with direct radiators (or leaking) is very inefficient at LF, but more flexible for different rooms and positions due to lower room gain and possibly inverted rear wave as super-cardioid.

[nc535]

Rotation R of upper side woofer D3 is +90 degrees (right) and lower side woofer D4 is -90 degrees (left).
Partial export 0...+180 deg from Diffraction tool works too. 'Mirror missing' must be on if drivers are rotated or tilted.

Thanks! I've got it now. Thinking about cardioid with smaller lighter drivers plus subs

Thanks also to admin for fixing my image.

[kimmosto]

Thinking about cardioid with smaller lighter drivers...

That could enable also fixed internal wall between front and side woofers -> different drivers and volumes -> different HP frequency at LF to create transition to omni for the lowest octave. So large sealed front woofers should be okay also for omni sub if closed side woofers are smaller with higher cut-off.

[draki]

Very often, a design with (relatively) flat In-room, ER and Power response shows a non-flat on-axis, at least IME. A typical 6-7" two way usually has a slight peak just below the Fc followed by a broad-ish and shallow valley after. Kind of a S-shaped curve, I am sure you know what I am describing here.
Obviously an ideal speaker would have all of them flat, but I am talking real-life, with imperfections due to many possible different reasons.
Hence this question: is it a good idea, and is it doable, to have an option of shaping the axial response target curve to other than straight line?

[Reet]

Very often, a design with (relatively) flat In-room, ER and Power response shows a non-flat on-axis, at least IME. A typical 6-7" two way usually has a slight peak just below the Fc followed by a broad-ish and shallow valley after. Kind of a S-shaped curve, I am sure you know what I am describing here.
Obviously an ideal speaker would have all of them flat, but I am talking real-life, with imperfections due to many possible different reasons.
Hence this question: is it a good idea, and is it doable, to have an option of shaping the axial response target curve to other than straight line?

You end up with an S curve as a result of differing directivity of each driver. With a fully "constant directivity" system you will be able to have constant slope to the response on all axis. Of course, with VituixCAD you can use any slope or curve as the target. You can generate any curve you like, load it as a file target in the optimizer. The pink target line will be replaced by the curve of the loaded file.

[kimmosto]

is it a good idea, and is it doable, to have an option of shaping the axial response target curve to other than straight line?

Custom target as txt/frd file is possible as Reet wrote, but I wouldn't create S target for axial because final target is still flat or shallow tilt down. Weighting between SPL and Power&DI graphs defines the compromise - how error is distributed between the graphs. 50/50 % allows quite much S-curve in axial so axial=60% power=40% could be better in many cases when using automatic Optimizer.

Answer would be different if off-axis data is not available. Then you are forced to guess how much S-curve is needed in axial to get e.g. flat predicted in-room response. But that's heretical from the Middle Ages which is kinda forbidden here.

[draki]

Agreed with all points.
For clarification, the question was more about the possibility of "shaping" the target curve directly, instead of importing externally created (which works, thanks for the tip, I have overlooked that!).
Not saying that reshaping a flat target is beneficial or not, but it was a useful "what if" exercise nonetheless.

[kimmosto]

2.0.69.1 (2021-05-19)

Impulse response
* Added Impulse response envelope (ETC) curve and checkbox.

[kimmosto]

Not saying that reshaping a flat target is beneficial or not, but it was a useful "what if" exercise nonetheless.

Optimizer window is possible to enlarge for two PEQs and one shelf, but something inside me fights against this because bump or dip at mid-range should not be target (especially axial). Just a consequence of compromise. Of course we can think that also consequence should be controlled (by human) better than two weighting factors and iterator minimizing sum of squared error can do. Target file with unlimited number of bumps and dips is easy to build with crossover network in another VCAD session so basically everything is already available, but not instantly available with controls integrated in Optimizer.

[fluid]

That could enable also fixed internal wall between front and side woofers -> different drivers and volumes -> different HP frequency at LF to create transition to omni for the lowest octave. So large sealed front woofers should be okay also for omni sub if closed side woofers are smaller with higher cut-off.

I also have 8 x Sica 5" drivers, would two of those on each side with the 15 on the front seem like a good idea? I bought them because they work well down to 100Hz in very small enclosures.

[Jack A Lope]

Hey Kimmosto I have a question. I have your software on two of my computers, a laptop running win 8.2 and my desktop running win 7. On my laptop all is good but I much prefer my desktop but there is a problem in the way the GUI is displayed. Some of the program is displayed truncated with parts of it inaccessible because it's outside of the viewable window and you can't make it any larger. This is especially prevalent with the SPL tracer tool where some of the data entry boxes aren't visible. Is this common or is there an easy fix?

Thanks for any help you can give.

[kimmosto]

2.0.70.0 (2021-05-20)

* Added optional Dash style for chart traces: Dash, DashDot, DashDotDot, Dot. Default is Solid.

[kimmosto]

Is this common or is there an easy fix?

I've seen that. I think it's display zooming which must be 100% on Win 7 and probably also Win 8. Win 10 is the first one where display zooming >100% actually works i.e. different Microsoft products support each other .NET Framework and operating system in this case.

[kimmosto]

I also have 8 x Sica 5" drivers, would two of those on each side with the 15 on the front seem like a good idea?

I believe it's doable - just like almost everything as fully active. Same driver model just enables simpler and more theoretical design without measurements and adjustments in large space because responses are identical. Just group delay with LP based on mechanical dimensions, and quick QC that it's close enough to super-cardioid.

[fluid]

Just group delay with LP based on mechanical dimensions

Is there a formula or guideline to this to get in the ballpark?

[fluid]

What would be the recommended measuring method for side firing drivers to use in Vituix for crossover and EQ simulation on a prototype?

[kimmosto]

2.0.71.0 (2021-05-22)

* Overlay traces are initially dashed (---).
* Dark background is drawn to SVG exports when dark theme is selected. Enables viewing also with light (normal) themes.

Main
* Axis and trace settings of Power&DI chart are saved to project file (.vxp). Not overlays.
* Aspect ratio set in Options window forced on when exporting Power&DI and Directivity as line or area chart.

Convert IR to FR
* File format of FFT session file (.vxf) changed. Chart settings are not read from files saved with older revisions.

[kimmosto]

Is there a formula or guideline to this to get in the ballpark?

GD ~ sound flying time from vertical center line of front baffle to center of side woofer + some extra because also box diffraction causes some LP causing extra GD.
In my example distance is 350 mm i.e. 1 ms. 10% more due to diffraction would be 1.1 ms. That happens with Bessel 12 LP @ 250 Hz.

[kimmosto]

What would be the recommended measuring method for side firing drivers to use in Vituix for crossover and EQ simulation on a prototype?

Measurement instruction are valid for conventional radiators such as side woofers: measure single driver at least 0-180 deg, driver's axis = hor 0 deg not matter where it points in final construction.
Obvious problem is that you should be able to measure just one driver at a time. Other side should be silent in order to support individual multi driver rotation and location with driver instances in crossover schematic. I might build prototype box for a single front woofer and single side woofer, and create simulation with those two data sets.

[kimmosto]

2.0.71.1 (2021-05-23)

Convert IR to FR
* Added Invert checkbox. Changes polarity of impulse response.

[draki]

A reality check question: when simulating a waveguided tweeter with Diffraction tool, is the driver diameter that of the dome or of the waveguide? What is correct?

[kimmosto]

Diffraction tool is able to simulate ideal flat circular or rectangular radiators. Nothing for wave guides and horns so they should be simulated with AKABAK or equivalent. Another option is to export directivity responses by measuring some actual wave guides and clone their directivity to some other driver.

[nc535]

Hi Kimmosto:
I really appreciate the several hints on cardioid. That really seems the way to go.

Dare I ask for a couple of features/tweaks:
* for those of us doing active speakers it would be great to be able to replace the Z graph with a directivity graph so we could see both H and V at once
* I have be really careful not to be moving the mouse when clicking to select block so I can tune a parameter. It would help to require a 2nd click before block can be moved - click once to select, click again and hold down to move

Thanks,
Jack

[Reet]

I also have issue sometimes with components moving when I only intended to select them. It just needs some delay for click and hold for movement, minimum 200ms click duration for example before component is moved.

[kimmosto]

Me too Dragging status was activated on mouse down which wouldn't be bad alone but there was also extra calculation when top selection was changed. That caused some delay to capturing of mouse up event so canceling of dragging status was delayed and component jumped. New build uploaded few minutes ago does not activate dragging before mouse has moved one snap, and extra calculation does happen if just selection changes. Should be faster and less jumpy.

[kimmosto]

* for those of us doing active speakers it would be great to be able to replace the Z graph with a directivity graph so we could see both H and V at once

This is not a bad idea and you're not the first one who is asking, but modification has high risks because polar response data and settings for user interface are partly mixed. I'm not happy with current structures inherited from VCAD version 1 so I will try to separate data and UI settings primarily for personal reasons; to make program easier to understand and maintain. This will open some new possibilities to show the same data in multiple charts.

First (and maybe the last) aid for limits due to single graph has been available for a while. Click directivity chart to focus it and then hit space bar to toggle between vertical and horizontal plane.

[kimmosto]

Second directivity graph with full features is coming to next revision. It's already done but systematic testing takes some time because modification was huge.

[fluid]

z

I don't know if something is wrong or if I am missing something but the directivity graph seems to have disappeared for me in the latest version. It is blank and when I right click on it to select polar chart or any other option it doesn't change. It is the same whether I have a driver loaded or not. I'm using Windows 10.

[kimmosto]

^Two possible reasons:
1) 'Disabled' selected in context menu of directivity chart.
2) Angle step = 0 deg in Options and no frequency responses loaded to Drivers tab.
Angle step = 0 deg stands for "measured directions only" so empty response list is kinda logical problem, though initial flat response exists also without loaded data.

[fluid]

^Two possible reasons:
1) 'Disabled' selected in context menu of directivity chart.
2) Angle step = 0 deg in Options and no frequency responses loaded to Drivers tab.
Angle step = 0 deg stands for "measured directions only" so empty response list is kinda logical problem, though initial flat response exists also without loaded data.

Line Chart is selected by default but I cannot select anything other than that or disabled. The power and DI works as expected when off axis angles are loaded



The Angle is set to 10 in the options

[kimmosto]

2.0.72.0 (2021-05-26)

Main
* Impedance chart can be replaced with second directivity chart e.g. to show both planes at the same time. Visible chart is selected with context menu.
* Polar chart overlays not deleted if chart type does not change.
* Added dashed line support to polar chart.
* Added legend to polar chart export as svg file.
* Aspect ratio set in Options window forced to Power&DI and Directivity exports as svg file.
* Added Hor/Ver plane to trace description of polar chart.
* Frequency scrollbar relocated to serve both polar charts as zoomed.

Convert IR to FR
* Added Bartlett, Blackman, Blackman-Harris, Blackman-Nuttall, Cosine, Hamming and Nuttall window functions.

This change was huge, but major bugs should not exist. Second directivity chart is full featured expect that settings are not saved to user config or project file. It starts as (disabled) Line chart with plane opposite to primary directivity chart. Other settings are program defaults.

[kimmosto]

but I cannot select anything other than that or disabled.

That sounds something I can't control. Win updates and reboots could help. Have you checked that file naming is okay i.e. angle parsing works?

[kimmosto]

Found! User's angles are checked. Uncheck that if you have not listed custom angles to Options.

[fluid]

Found! User's angles are checked. Uncheck that if you have not listed custom angles to Options.

Thanks, that did the trick

[kimmosto]

Just uploaded new build of 2.0.72 which prevents that situation.
- Not possible to check 'User's off-axis angles' if both angle lists in Options are empty.
- Status of 'User's off-axis angles' is saved to and read from project file if angle lists contain something. This is for those who measure and simulate just custom angles, but nothing else.

[draki]

Works here too