VituixCAD v2

[kimmosto]

2.0.111.3 (2024-02-14)

Enclosure; Add/Edit driver, Calculate T/S

• Parameter limits adjusted.

---

2.0.111.2 (2024-02-13)

Enclosure

• Fixed trace values in Power chart. Calculation was using wrong impedance variable.

[Reet]

kimmosto Just in case you haven't noticed, the latest beta releases of REW are now including an API for external integration. I know you have stated that you have no intentions to include measurements within VituixCAD because perfectly good software already exists for that, however perhaps there is some opportunity for integration there. I'm not asking for anything, just want to put it on your radar.

https://www.avnirvana.com/threads/re...eleases.12981/

https://www.roomeqwizard.com/help/help_en-GB/html/api.html

[JonMarsh]

well, I am guilty of designing stuff with 4 PR's per cabinet... and I figured 8 would be really over the top!

[kimmosto]

Directivity chart uses Ref. angle you have selected from here

It is saved to project's vxp file to be project dependent.

[tktran]

Hi,

I noticed today that my Directivity Chart uses the 15 degrees axis as the Reference. Have I accidentally changed an option that made this so?

eg.


I have the most recent release of VituixCAD2.

[kimmosto]

Limits look overshoot but it's mostly just keeping voltage and power units compatible down to Re=2 Ohms in Enclosure and down to 4 Ohms in Power dissipation window.
Significant part of (paying) VituixCAD users are pro audio so power amps 1-7 kW are possible. Enclosure tool does not directly understand multiple power amps while simulating multiple drivers so for example 9 drivers need 3||3||3 correction and voltage signal x3 or power signal x9.

Also original max limit of passive radiators was logical error because typically one active driver needs 1-2 passives so 24 passives is proper max limit. It's not necessarily wise decision because vented is usually easier and cheaper with large enclosures having enough room for relatively short vent. Vented small boxes are more difficult so 1-4 passive radiators is tempting solution.

[Reet]

Some lunatic on DIYAudio asked for higher max power and at least 12 passive radiators. I'm not going to ask why.

[JonMarsh]

Downloaded this morning... before seeing this! But, um, 40kW? Wow! ;^)

[kimmosto]

2.0.111.1 (2024-02-10)

Main

• Show ±45 deg in context menu of directivity chart enabled for Polar chart.
• Generator's default maximum voltage increased to 283 V.

Power dissipation

• Maximum voltage increased to 283 V.
• Maximum power to 8 Ohms increased to 10 kW.
• Maximum power to 4 Ohms increased to 20 kW.

Enclosure

• Maximum signal voltage increased to 283 V.
• Maximum signal power increased to 40 kW.
• Added current (A) trace to Power chart.
• Maximum number of passive radiators increased to 24 pcs.

[Reet]

Marketing speak for reducing assembly steps and parts cost

[mecedo]

...have you listened to the Diapason Adamantes acoustics?

From their speakers description:

...a newly designed, thick printed circuit board is directly connected to the loudspeaker terminals to ensure the most direct and fastest possible transmission of the electrical signal to the speaker membranes. According to the minimalist interleaving concept, only a few components were used to enable the most direct and fast transmission of the electrical signal...

O M G !!!!

[kimmosto]

have you listened to the Diapason Adamantes acoustics?

No..

[Nil L]

kimmosto, have you listened to the Diapason Adamantes acoustics? If yes, then say something about it.

[kimmosto]

Some balancing problems exists also with very small speakers with small wave guide, because small box itself creates directivity with diffraction.
This is existing commercial design with 4" woofer and 1" dome. Diameter of circular wave guide is just 100 mm, and depth 20 mm. LW is normalized with slope = -0.13 to get ON slope to 0 to the graph and PR table.

This produces PIR slope = -1.476 and SP slope = -2.40.

Both numbers are clearly off my previous specs so I would have to tilt on-axis up by ca. slope=+0.4 to full-fill my own standards. I will not do that because too much heated treble creates "quasi resolution" i.e. actual resolution achieved with bad method such as excessive on-axis level on tweeter's range. Sound edges and bling-bling would sound clear, but it's not natural and relaxed for long listening periods. So this speaker will have compromise; small tilt up but ON slope < +0.3 and LW slope < +0.1. Much less tilt would sound too dull and muffled in decent room acoustics. Target environment is probably worse so all good I hope.

Heated treble wasn't rare in Finnish speakers when popularity of wave guides increased few decades ago. That became a standard long time ago. Nowadays hifi enthusiasts have noticed that room acoustics (mostly with diffusers) is proper cure and too large and deep wave guides are not. I can see positive attitude towards wave guides on international discussion forums, but expecting that people start to listen and hear that more than just linearity of some calculated curves is needed.

[kimmosto]

Where does the determination that a certain slope is preferred come from? Last I knew, Toole, et al. left that specific question open when they developed their preference scoring. Is there another group that has carried on this research?

In this thread it's just my experience and opinion. I guess someone educated has tried to find some range for preferred slopes, but as I mentioned earlier, there are many variables which makes difficult to recommend range for a single variable such as PIR slope or SP slope compared to ON/LW slope "as a scientist".

Harman's earlier listening room was quite large and it had mostly (styrofoam?) diffusers on the walls and ceiling. That is not typical listening environment making me think that it could provide (too) narrow sight and results are not very representative. RT60 was maybe ca. 400 ms, but EDT was not published. We all (at least should) know that RT60 does not tell anything about achieved acoustical resolution so it's kinda worthless as a number. EDT and spectrum tell more.

Back to slopes. Strength of directivity is one tool to increase acoustical resolution, but it's not good method if e.g. DI=0 dB at LF and > 10 dB at HF. Steep DI slope with small DI at LF is not compatible with rooms having good EDT at mid...high to get good acoustic resolution on wide frequency range with any speaker concept. High DI at HF could help with bad and harsh acoustics, but then order of improvement actions is reversed. Really wrong imo. spinorama.org and many members (including webmaster) on ASR don't seem to care or understand anything about this. They just look linearity of ON, LW and especially PIR curve because "Olive's PR says so", and say wow! for straight lines. Almost no one protest against e.g. Neumann KH 150 which sounds dull dead with burned tweeter in living room having some (painted) acoustic panels on the walls and ceiling, and large carpet on the floor. Sound is unworthy almost everywhere outside on-axis. Ok, it's near field monitor, but also in that group very unbalanced in decent listening environment though it is said to be "one of the most flat frequency responses ever seen". And it's not the only one. March Sointuva, Buchardt P300..S400 etc. look the same concept.

Speakers with very strong directivity such as tractrix horns with cardioid bass or dipole panels change the game so that they are not usually listened casually / much off-axis. No one cares (to say) if balance is bad or otherwise strange to 70...180 degrees off-axis.

Opposite end is flush mounted wall speakers which are almost omni to half space. See the following spinorama. Sound is very good, balanced and open to very wide and tall area also in decent room acoustics. Slope of on-axis can be balanced to negative to get PIR slope close to "good" value for full space concept. Sound fills the room and balance stays stable due to very small slope of DI.


So I encourage to listen and compare and use own brain rather than just reading n' believing Olive and Toole.

[tktran]

Here is my speaker, hand tuned by IIR DSP:

I'm also using XT25 (BG60) variant, but without waveguide.

Some comments about the top octave- IMHO fine tune to taste (ie. personal listening room acoustics, hearing preferences, musical program material)

[kimmosto]

Do you mean that the calculations in this comparison are different from what is shown in the preference rating window of VituixCAD?

Slope results are the same with all three equations, but SM results are not. Olive's equations (9) and (10) have some built in intentional biases or unintentional mistakes. SM result depends on slope. Slopes close to 1 and -1 give better SM result than slopes close to 0 with equal variations. NBD has the same problem, but NBD prefers slope=0. Equation 9 has NBD_PIR so result is not perfect with perfectly linear PIR.

Custom equation (the last one) eliminates slope from SM and NBD result, and has separate slope targets so it is the only equation what I can recommended for speaker designing.

More information in user manual: https://kimmosaunisto.net/Software/V...ference_rating

[Reet]

Start here:

https://shop.cta.tech/products/standard-method-of-measurement-for-in-home-loudspeakers

https://patentimages.storage.googleapis.com/95/03/0a/a4a8dbd7d8042c/US20050195982A1.pdf

[draki]

Will somebody explain a little these new (at least to me) charts please? 🤔

[augerpro]

Where does the determination that a certain slope is preferred come from? Last I knew, Toole, et al. left that specific question open when they developed their preference scoring. Is there another group that has carried on this research?

[Reet]

Some statistics with subjective classification: green=good, orange=maybe, red=bad. Calculations done with "custom" preference rating due to better math.

Do you mean that the calculations in this comparison are different from what is shown in the preference rating window of VituixCAD? For my speaker, PIR slope is -1.311, SP slope -2.159, so I will put it on the border of "maybe" and "good" category based on this chart. Bringing down the high frequencies in the top octave puts it in "bad" category.

[Reet]

This type of construction is still a bit complex to me, however I may attempt something along these lines for the next build.

[Reet]

You seem to have fitted carpeting which reduces reflected power at HF. Have you measured acoustical parameters at typical listening area? I'm interested in EDT and T20 spectrum. ARTA is good in that task. Probably REW too.

I am fortunate to have quite a good listening space. Eventually the carpet will go and I will have to rely on some heavy rug and tapestries. We also have 100 house plants, and the space behind the listening location is not a flat wall, but open stairwell. It is also a large enough space that I can listen at nearly 5m distance.

I'm not well experienced with RT60 type of measurement and interpretation, but I will be setting up for measuring a few more speaker drivers in a week or two, and will plan to investigate this topic a but further then. The waveguide on the XT25 also assists in distortion at 2kHz range by providing a bit of boost to forward facing angles. I find the overall sound balance of this speaker to be very good, neither bright nor dull, "just right".

[kimmosto]

Active 2-way with S-S 18WU-4741 and D3004-660000


Prototype cabinet. Final will be rounded to smooth DI and "mute" time domain.

Point is again that PIR and SP slopes are very good without wave guide. Very shallow wave guide could smooth DI, but too deep could tilt too much.

[kimmosto]

For a reference to previous table; Avalon style floor standing 3-way with Seas L22RNX/P, Seas MCA15RCY and Scan-Speak D2904-600001 classic soft dome. Preliminary box finishing without rounded bevels.

Indicates that modern 2-way near field monitors with deep (or any) wave guide are not far from useless crap especially for casual listening if room has acoustic panels, soft carpets etc.

[kimmosto]

tweeter is old XT25TG30 ring radiator in Visaton WG148 waveguide.

That combination is not very flexible maintaining sound balance in different acoustical conditions and listening directions. You seem to have fitted carpeting which reduces reflected power at HF. Have you measured acoustical parameters at typical listening area? I'm interested in EDT and T20 spectrum. ARTA is good in that task. Probably REW too.

Usually plastic and paper cones 4.5"-5.25" don't need wave guide, but ring tweeter may need some boosting at HF to compensate "excessive" directivity at top octave, especially if listening area is very large.

[kimmosto]

Some statistics with subjective classification: green=good, orange=maybe, red=bad. Calculations done with "custom" preference rating due to better math.

[Reet]

Thank you for your insight. If I understand, end result is that there is no one size fits all criteria for balancing on-axis and power response, especially at the extents of the hearing range. Make it sound good to you in your space and move on. I do want to make note, that the top-end rise I do not find offensive, bright, or "hot", in fact I find the speaker quite balanced. I will make some adjustments with external EQ, so I can A/B compare the two responses above and see if I have a preference, or can even tell the difference between the two.

FWIW, this is the speaker used for the example, tweeter is old XT25TG30 ring radiator in Visaton WG148 waveguide.

https://www.htguide.com/forum/forum/mission-possible-diy/947504-disco-on-the-floor-p

[kimmosto]

...which will be preferred? ... What do you think?

Fortunately top octave can be hot so wave guide or some diffuser is not must with domes and ring radiators. For example Scan-Speak's rings could sound quite dry and dull to off-axis, but they also tolerate longer listening distance.
Generally all this is really complex equation. Much more complex than Olive's Preference rating and reviewers can ever handle. Result depends on room acoustics; length and spectrum of EDT and RT60, location of absorbing panels and carpets, location of diffusers, location and materials of surfaces without acoustic treatment, listening distance, speaker locations, need to listen radically off-axis (in different room), strength of directivity, tilt (dB/oct) of PIR/SP slope, shape of PIR/SP slope, location of woofers and ports in cabinet, SPEAKER CONCEPT and much more.

[Reet]

Another forum had posed a question regarding on-axis lift in the top octave when tuning the overall response. I have personally found that using listening window average is a more useful metric for tuning than single axial response, so ending up with a bit of axial lift provides some better balance in a normal listening situation. I am just wondering if anyone else has any insight/opinions on the subject here.

Here's a simple example, This speaker includes a lift in the top octave, in order to achieve a better slope to listening window, in-room, power response.

Alternatively, this speaker could be tuned for a flatter axial response, which results in a drooping power response. Typical behaviour for many speakers.


But, which will be preferred? If "preference rating" is a good metric, first equation provides very much the same result, with the first option receiving a better rating by 0.1. The second equation gives preference to the second option by about 0.6. Generally speaking, I don't put much importance in the top octave anyway, so this is small details, but one solution must be "better". What do you think?

[kimmosto]

2.0.111.0 (2024-01-05)

Calculator

• Removed 'Product of A responses'.
• Removed 'Directivity of A responses'. Use main program instead due to features and accuracy.
• Removed 'Power of A responses'. Use main program instead due to features and accuracy.
• Added 'Average by off-axis angle A'. Calculates average of the same plane and angle.
• Added Plane column to A responses
• Added possibility to sort A responses by Filename, Plane or Angle by clicking header.

User manual:
Average by off-axis angle A
Calculates average of the same plane and angle. This is handy when crossover is designed with several driver samples having some real life tolerances i.e. differences in frequency responses. All measurements of drives samples are loaded to A responses. Program sorts response list by Plane, Angle and Filename, and calculates and exports average of each off-axis group to response files which can be loaded to Drivers tab in the main program.
Result's magnitude is arithmetic mean of magnitudes to avoid magnitude drop due to possible delay differences between acoustical measurements to the same off-axis direction. Result's phase angle is vector sum to avoid phase unwrapping (which would be required for arithmetic mean). 'Complex Sum/Avg/RMS' is unchecked and disabled to force previous settings.
Note! 'Angle parsing from filename' settings in Options must match with loaded frequency response filenames to get correct values to Plane and Angle columns.

Default result filename prefix is AvgByDir, followed by plane and off-axis angle of the group. Angle coding uses current 'Angle parsing from filename' settings in Options (so you can also change angle coding e.g. from 3D balloon to generic 2D).

[kimmosto]

Happy Holidays!

The latest build of 2.0.110.3 (2023-12-25) finally includes short instructions and few screenshots for Create project sub-folders -feature. That was promised already few months ago with 2.0.110.0 (2023-10-28), but repeatedly forgotten.

Some small but probably invisible logic tweaks has also done to trace widths of Directivity charts. Width difference between "normal/thin", selected and on-axis traces is not yet changed. Selected trace is +1px and on-axis is +2px so they might be difficult to distinguish with 4K display. I also tested multipliers such as 1.5x and 1.7x base width. Multiplier is probably better with 4K, but worse with e.g. 1920x1080px (which I always use though screen of my 17" laptop is native 4K).

[Reet]

Thank you, and Happy Holidays!

[kimmosto]

2.0.110.3 (2023-12-24)

Main

• Line width of line, waterfall and surface directivity charts saved to user settings for the next session.

[Reet]

Is there a possibility to make 2px line thickness for the directivity line chart a default setting? Ever time VituixCAD is closed, or if just the chart type is changed, the line width is set back to 1px.

[kimmosto]

2.0.110.2 (2023-12-13)

Diffraction

• Eliminated program crash (related to automatic Y axis scaling) if magnitude traces are hidden.

Calculator

• Automatic Y axis scaling with A button skipped if magnitude traces are hidden.

[kimmosto]

Extrapolation from 5 Hz down to 0 Hz has always been problematic, and I can almost promise that changes in 2.0.110.1 are not the last.
Previous versions had small bug for several months; real and imaginary part of 0 Hz point was zeroed with all LF slopes, but zeroing was not (accidentally) done to 0 Hz point of "mirrored" frequency response which fills the second half of the FFT buffer. Now both ends are zeroed, but possible problem is that filter of woofer could extend down to 0 Hz. 0 Hz point is not necessary to zero if there's no HP slope at LF.
Much older versions detected LF slope and zeroed or copied values from the next frequency point to 0 Hz if slope is < 3 dB/oct. That was expected to be better approach, but somehow I wasn't happy with it. Maybe it should be evaluated again.
Full range flat frequency response produces natural DC offset to impulse response. That's not a problem, but some DC variation (easily visible in step response) could exist with almost any real life IR depending on combination of sample rate, FFT length, taps and window function because limited part of IR could include DC offset also with high passing slopes.
So there is no perfect solution for FIR with truncated frequency range and limited taps. Some errors will exist at LF.

[Reet]

Excellent update today, thank you.

2.0.110.1 (2023-12-05)

Impulse

• Magnitude and phase extrapolated as zero at 0 Hz to reduce DC offset in impulse response.

[kimmosto]

I think I have a bug- the main screen, moving drivers up or down in the list to reorder them.

in the crossover screen, this order is not reflected there.

Schematic must not change a bit when driver list is re-ordered. There is no such AI which could redesign all possible circuit topologies and connections so that drivers are in certain graphical order from top to bottom without messing up whole wiring and visual clarity. All crossovers are not simple parallel ladders with single driver for each band where that kind of feature would be possible.

[tktran]

I think I have a bug- the main screen, moving drivers up or down in the list to reorder them.

in the crossover screen, this order is not reflected there.

[HTDT89]

Ah, yes, I see. Obvious! Sorry I didn't think to check traces.

[kimmosto]

^Value of Rs and other filter components control visibility of green traces called 'Impedance Magnitude/Phase with passive filter'. Raw impedance without passive components is dark trace (WindowFrame by default). It is normally visible, but possible to hide for good. Check Show cell in Traces window, and it should stay visible also in the next session. I usually click View->Default colors in the main program to restore 'factory defaults'.

[HTDT89]

kimmosto, I believe there's a small bug in the enclosure tool. The impedance curve does not plot when filter tab's Rs = 0. Because Rs is not remembered when closing the tool, there is no impedance graph when you first open it or manually reset Rs to 0.

I am running latest, v2.0.110.0.

Other than this, the embedded filters are great. Much easier workflow than jumping between crossover & enclosure for this basic analysis.

I am a slow thinker, and it took some time to digest your input.
I have gained significant insights from our conversation, thank you very much.
I am sorry I made you upset.

I absolutely agree. You cannot understand my questions and I cannot understand your answers.
It must be me who is too stupid.