VituixCAD v2

[Reet]

I am reminded of a paper from Bohdan Raczynski from a few years back "Perfecting 'Punch' In Your Loudspeakers", here:

https://bodziosoftware.com.au/Perfecting_Punch.pdf

The paper makes no reference to step response however, but there references at the end to a lot of related research which may be of interest.

Complete list of papers and internet sources
1. M.Zaunschirm, J.Reiss and A.Klapuri, A High Quality Sub-Band Approach to Musical
Transient Modification, Computer Music Journal, Volume 36, Number 2, Summer 2012,
pp. 23-36

2. M.Goodwin and C.Avendano, Enhancement of Audio Signals Using Transient Detection
and Modification, AES Convention Paper 6255, October 2004

3. "Detection and modeling of fast attack transients" by Xavier Rodet and Florent Jaillet

4. S.Fenton., B.Fazenda, and J.Wakefield, 'Objective quality measurement of audio using
multiband dynamic range analysis'. Institute of Acoustics (IOA) Conference- November
2009,

5. S.Fenton and J.Wakefield, Objective profiling of perceived punch and clarity in produced
music.132nd Audio Engineering Society Convention, April 2012,

6. Steven Fenton, Hyunkook Lee, and Jonathan Wakefield in "Elicitation and Objective
Grading of 'Punch' Within Produced Music" Convention Paper 9043, Presented at the
136th Convention 2014 April 26–29 Berlin, Germany,

7. Hybrid Multiresolution Analysis Of 'Punch' In Musical Signals. Steven Fenton,
Hyunkook Lee, and Jonathan Wakefield, Convention Paper 9229 Presented at the 138th
Convention 2015 May 7–10 Warsaw, Poland

8. Towards a Perceptual Model Of 'Punch' In Musical Signals, Steven Fenton and
Hyunkook Lee, Convention Paper 9381Presented at the 139th Convention 2015 October
29-November 1 New York, USA

9. Peter Dowset ―Audio Production Tips: Getting the Sound Right at the Source‖, CRC
Press, 538 pages.

10. URL Source: http://www.stereophile.com/reference/706deep/index.html

11. http://music.tutsplus.com/tutorials/...-mixes--audio-
1083

12. http://subaqueousmusic.com/transient...-to-add-punch/

13. http://www.thesoundkeeper.com/top-5-...esign-plugins/

[kimmosto]

It appears that this is not strictly a magnitude response problem, the time domain is just as important.

Possible differences in magnitude responses, directivity, wavefront, compression/dynamic features of the radiators (including ports) and location of the radiators make difficult to evaluate effect of time domain only. Therefore the only controlled method to distinguish timing is to compare the same speaker with different phase linearisation with FIR gear/app: from minimum-phase version via original timing to added excess group delay. Test speakers should be dynamic, preferably closed to have short group delay at LF, and wavefront towards the listener to not limit perceptibility of timing with something else than timing of the source.

The only study and convention paper including close to proper method is "Audibility of Loudspeaker Phase Distortion" by Greenfield and Hawsford, 1990. Test speaker was Celestion SL700 (2-way with XO at 3 kHz) and they listened two music tracks only. That study is not valid to tell anything about 3...5-ways or using subwoofers crossed at mid...high-bass. So insignificance of time domain is just religious cult in "objective" forums such as Audio Science Review.

[Reet]

The most ideal phase and step response with certain magnitude response is minimum-phase. Step response like with Dunlavys.
That is possible to set as a reference overlay by selecting "Total SPL MP" to 'Signal to show' list box and locking Y scale with IR max checkbox. For example this in theoretical limes for 8260A shown below, assuming that speaker would have adequate phase linearisation with FIR convolution:

Thank you, this is quite helpful. It aligns well with my own perception, from previous examples shown, speaker 2 has the most impactful, "punchy" bass, despite a quite modest mid tier driver being used. It appears that this is not strictly a magnitude response problem, the time domain is just as important.

[JonMarsh]

Thank You! I should be looking closer, but I've been working on cabinets and hardware so much lately!

[kimmosto]

I would request a built in Duelund Reference transfer function generator for VituixCAD- you only need two input variables to define it relative to 0 db, but one could always add a scaling function for extra credit!

VituixCAD has two Duelund active 3-way library blocks using generic active blocks. Two parameters: f and a.

It also has two Duelund target transfer functions for LP/HP and BP, defined in Optimizer window. These are designed for passive 3-way speakers. May require some knowledge or testing how f and a should be set:

[kimmosto]

Is an ideal response to have a flat RMS step, or some sort of slope to this curve?

The most ideal phase and step response with certain magnitude response is minimum-phase. Step response like with Dunlavys.
That is possible to set as a reference overlay by selecting "Total SPL MP" to 'Signal to show' list box and locking Y scale with IR max checkbox. For example this in theoretical limes for 8260A shown below, assuming that speaker would have adequate phase linearisation with FIR convolution:

Reality with early production series and original GLM is quite much lower maximum pressure and RMS compared to minimum-phase:

Perceivability of pressure drop with ears and body is more complex topic. As far as I know, there are no valid studies and convention papers available for that. Perceivability depends on many other things too so it's difficult to define minimum group delays for speakers without FIR gear/app. Designers are forced to use their own experience or design principle without requirement for any psycho-acoustic science. Minimizing excess group delay and avoiding subsonic filter and subwoofers is quite safe way, but for example pro audio sector could have some higher priorities such as total latency and durability which could prevent from aiming for zero excess group delay and short GD at LF.

[JonMarsh]

To be sure everyone understands, just kidding...
But it would be useful, to me.

[JonMarsh]

Now, if Kimmo doesn't have enough to do, and is looking for a new extra credit homework assignment, I would request a built in Duelund Reference transfer function generator for VituixCAD- you only need two input variables to define it relative to 0 db, but one could always add a scaling function for extra credit!

[JonMarsh]

Generating a transfer function set and exporting these to a text file, they can be imported into VituixCAD to use as response target references.

[JonMarsh]

And, for anyone interested, a quick reminder of how Duelund filters work...


the individual LP, MP, HP equations and total transfer function, based on a defined center frequency and coefficient aleph:




MathCAD plots for different coefficients of aleph:





Phase examples for those versions of aleph:





For an aleph of 1.414 or less, the transfer function devolves to a two way.

[JonMarsh]

OK, it's not a slow Saturday morning here, but this is a long time favorite topic of mine, so I thought I'd drop by with a hint or two, or rather, observation and passing explanation for commercial loudspeakers.


Let's consider the measured step response of two commercially available loudspeakers that are fairly well known (well, in some quarters). The Magico M2, and the Vimberg Mino. Both are three way speakers. Vimberg is sort of a subsidiary of Tidal Audio as I understand it, and I love the esthetics and design choices, and they were an influence in the Ardent D project.

So lets look at the step response, courtesy of online reviewers


Magico M2



Scuttlebut says the Magico's use a multi-way LR4 crossover.



Vimberg Mino






Scuttlebut and Stereophile review describes a crossover that sounds an awful lot like a Duelund variation- certainly possible to achieve with the drivers chosen.





A key requirement is having the effective acoustical Z axis origin in the same plane, and the Accuton aluminum sandwich woofers do a good job of meeting that requirement. These appear to be customized versions of the AS168-9-470.

[Reet]

How best to interpret "RMS of Step after pre-delay"? Is an ideal response to have a flat RMS step, or some sort of slope to this curve?
I have 3 examples below of 3-way tower speakers, each with quite different unique features. Which is okay, great, or awful as far as the step response is concerned?
Speaker 1:


Speaker 2:


Speaker 3:

[kimmosto]

2.0.127.2 (2025-07-08)

Main

• Added 'Logo height' text box to Options window. Height is defined as percent of chart area height. Range is 5-25 %.
  So logo file can be HD, and program scales it down to specified height.

Impulse

• RMS checkbox updated if visibility changed in Traces... window.

M-S Defender has started to nag and block/delete VituixCAD2.exe with few users. May be due to new obfuscator version: Eziriz Intellilock 3.5.0.0. VirusTotal reports Trojan:Win32/Wacatac.B!ml with Microsoft's scanner. No alerts in my PCs so this could be false alarm.

[kimmosto]

any details about the specific speaker?

The 1st Ones. Measurement was done in 2012 -11. I don't know if the excess delay was reduced (about a decade) later by updating the firmware and GLM.

In current models such as this Ones, the issue has been fixed by linearizing phase within allowed latency limits to input signal. That doesn't produce perfect minimum-phase response even in "extended linearisation mode", but it's better than the older active 3-way models. Transients also sound stronger and soundstage is more logical than earlier, but subwoofer can/will still damage timing at bass.

[JonMarsh]

Great example... any details about the specific speaker?

[kimmosto]

Once again my favorite timing example with new 'RMS of Step after pre-delay' traces.
Actual loudspeaker, flawless magnitude responses and directivity, but otherwise 😭 Very confusing experience to listen speaker with so much right, but still too much wrong.

[kimmosto]

They should really drop "Science" from the name IMO.

Harman's research (R.I.P) focused on the most significant and easily audible parameters to conquer the low- and mid-priced consumer market. Basic sh*t for everyone except hi-fi enthusiasts. At least that would explain why they filtered out almost everything else than parameters based on magnitude response variations. The result of this work was generalized to "listener preference" which was chosen as the law book and the bible of loudspeaker reviews on ASR. Few other subjectively selected parameters are measured, and the rest have been arbitrarily discarded though errors can be objectively radical. That shouldn't affect to loudspeaker designers, but at least some other manufacturers have made mistakes by trusting narrow and/or invalid old studies and simplifications by Harman. Some may optimize their products to succeed in certain "objective" reviews and measurements such as CTA-2034 by Klippel NFS.

I don't want to support forum acting like that so my collaboration with VituixCAD has ended. Next step would be ending public releases so I hope ASR begins to show development and openness to clearly measurable errors even if they are not within Harman's consumer-level preference.

[Reet]

I don't find there's much DIY effort going on there regardless, the DIY section of the forum is quite barren compared to the rest of the forum. They should really drop "Science" from the name IMO.

[kimmosto]

You may need a legal team to enforce that one, but I commend your efforts to thwart misuse.

I don't try to enforce. Just recommending some other forum such as diyaudio or HTguide especially for loudspeaker DIY. ASR is too toxic, religiously limited, hopeless, authoritarian and nowadays commercially connected too so DIY community could exit for good.

[Reet]

"You may not publish any material produced or processed with VituixCAD on Audio Science Review (ASR) Forum"
You may need a legal team to enforce that one, but I commend your efforts to thwart misuse.

[kimmosto]

dB/octave slope of a curve

Tooltip indicating X, Y and Y2 values and name in a tiny borderless window at mouse cursor is global constant feature of chart class i.e. the same code serves all line charts in the package.
I'm not very keen to make additional custom code for some individual chart.

driver impedance using a logarithmic scale

Chart class does not support logarithmic Y scales. Logarithmic scale has been programmed for frequency X axis only. Of course dB scale is kinda logarithmic, but the values are saved as linear in dB.
Logarithmic Ohm scale has always been very annoying imo. "Certain" inductance behavior can be detected with single series coil (Ls) though unrealistic clean Le is quite recognizablewithout log scale anyway.

[kimmosto]

2.0.127.1 (2025-07-05)

• License updated.

Main

• Crossover schematic dimensions extended from 200x140 to 400x300 coordinate units.

Impulse

• Added RMS checkbox. Shows quadratic mean of step response after pre-delay.
• IR view tab and chart renamed to Time domain.
• FR view tab and chart renamed to Frequency domain.

[witwald]

For your consideration, I would like suggest a new feature for inclusion in VituixCAD's Enclosure simulation tool.

Would it be possible to have an option to display the magnitude of the driver impedance using a logarithmic scale? This would make certain log-linear behaviour characteristics much easier to identify.

[kimmosto]

2.0.127.0 (2025-06-21)

• Added 'Export data' button to Traces window. Exports data points of all or selected traces to txt/csv file and clipboard.

Power dissipation

• 'Export chart data' command removed from context menu of chart.

Enclosure

• 'Export six-pack data' command removed from context menu of charts.

[kimmosto]

2.0.126.1 (2025-06-18)

• In frequency response smoothing, the imaginary and real parts of the phase response are smoothed separately without phase unwrapping.
  Magnitude smoothing has not been modified.

Main

• Frequency axis maximum value updated on XO variant change.

[witwald]

For your consideration, I would like to ask that a new feature be added to VituixCAD's Enclosure simulation tool.

Often when I am performing an enclosure analysis/study, I find it is useful to know the dB/octave slope of a curve at various points. The cursor already has the facility to display the (Hz, dB, phase) associated with any given point on the chosen curve.

Would it be possible to also display the local slope of the curve in dB/octave?

Thank you for considering my feature request.

[kimmosto]

2.0.126.0 (2025-06-06)

Main

• Added 'Clean user.config' command to Help menu.

Enclosure

• Added Quasi-Chebyshev alignment to Align tab.

[kimmosto]

Perhaps VituixCAD could do some automatic cleanup, only retain config file for last version or something to that effect.

This is already done and tested, but single 'Yes to all' button would be faster than 90 times Yes 😀. Standard message box does not have Yes to all so it requires custom window.

[Reet]

Anyway, user.config system of .NET is quite flexible and automatic but complex too. Some settings could go bad if there are too many directories and config files for multiple revisions. I occasionally delete all directories except for the last version.

Yes, that's what I did effectively. Deleted all directories, tested normal operation, then put only directory for current version back. Perhaps VituixCAD could do some automatic cleanup, only retain config file for last version or something to that effect. I did have around 90 revisions in there

[kimmosto]

It says "Auto update, latest2.txt Version string portion was too short or too long."

Ok, it's the same error as before. New version tells filename to download: latest2.txt or VituixCAD2_setup.exe.
Basically programs just reads content of https://kimmosaunisto.net/Software/V...AD/latest2.txt
Program should be able to read it as easy as any web browser. Too short is e.g. 2 (less than two levels) and too long is 2.0.125.1.7 (more than four levels).

Anyway, user.config system of .NET is quite flexible and automatic but complex too. Some settings could go bad if there are too many directories and config files for multiple revisions. I occasionally delete all directories except for the last version.

[Reet]

Hmm, very odd the screenshot isn't showing. Let me try again:

It says "Auto update, latest2.txt Version string portion was too short or too long."

I'm not sure what the problem was, but I'm not getting the error anymore so we can forget about it for now. I have changed main directory, but nothing has changed there for a few years, folders are writable, have free space, etc.

I saved the config file before removing it from AppData folder if you'd like to review. It is attached, renamed to .txt to get around forum limitations.

Thanks for taking the time to look into it.

[kimmosto]

I have a different message:

Image with message is not visible here, but I guess download directory could be the problem because it's the only one related to user.config. Default download directory is "My Documents/VituixCAD/Download" but Main directory -setting in Options overrides that. For example my Main directory is "C:\Users\Kimmo\OneDrive\Documents\VituixCAD" so download directory is "C:\Users\Kimmo\OneDrive\Documents\VituixCAD\Downl oad". Download could fail if user.config is bad or download directory does not exist i.e. creation of directory fails or you don't have adequate access rights to it.
Next revision will try to create download directory right before download (not in program start-up), but that does not guarantee success if Main directory -setting in user.config is bad.

[Reet]

Manually downloaded the latest, I have a different message:


It may be a problem on my end, I deleted the config files from AppData/Local/Kimmo_Saunisto/*, it appears to have resolved it. Very confusing, I put the old config file back in place and the error has not returned. Who knows, but it's good now.

[kimmosto]

2.0.125.1 (2025-05-31)

Main

• Auto update is using HttpClient instead of (obsolete) WebClient.

Enclosure

• Online database is downloaded for browsing and database update using HttpClient instead of (obsolete) WebClient.

Merger

• Raw LF response traces try to maintain line width, color and style set in Traces window while current session.

Replacing WebClient with HttpClient class may not have any effect, but it should be more modern. This version should be downloaded and installed manually if previous versions and server do not co-operate anymore due to newer PHP version 8.2 at the server. Co-operation is tested automatically by Auto update in every start-up, or can be tested manually by browsing Online driver database in Enclosure tool.

[kimmosto]

^Works here but it does not prove anything because service provider is changing PHP support. Earlier PHP setting was 7.4 or some other old which will be removed from the server on Tue 2025-06-03. My new selection has been 8.2.28 for few days, but I just changed to "8.2.21 by OS vendor". It should be running already, but won't probably help due to same major version.



I'm not sure is this the problem and why, but this is the only thing which has changed since the previous revision.

Microsoft says that WebClient class VCAD is using for download is obsolete and should be updated to HttpClient. That probably enables downloading without PHP support so I'll make some tests and changes to auto update in few weeks.

[Reet]

Error with auto-update. I'm on version 2.0.124.1

[kimmosto]

2.0.125.0 (2025-05-30)

Main

• Calculation of front wall reflection in Room tab fixed with Distances > 90 m.

Enclosure

• Added Shelv HP to Filter tab.

Merger

• Phase responses shown on start-up.

[Reet]

Minor bug observed in the merger tool, "show phase" is checked by default when you open the tool, however phase is not shown until the box is un-checked and re-checked.

[witwald]

No, I haven't tried using an L-T with the B&C 18SW115 driver. The example L-T that has been provided above seems to essentially be a PEQ of +4dB at 40Hz with a low Q value, albeit with a fraction more boost at 10Hz than a simple PEQ would be expected to provide.

[kimmosto]

^I guess you haven't tested L-T for your B&C 18SW115 case? That includes shelf and two PEQs though the shelf is still LP. 'Hole in one' in theory, but more difficult to iterate manually.

[witwald]

The UI panel as shown, with the Shelv HP control added, would be excellent for my purposes. 🙂 I anticipate using it regularly when suggesting possible subwoofer designs in answer to queries about this driver or that driver. I'll be able to achieve a flatter response in the typical subwoofer passband, while at the same time allowing clear communication of the ensuing power requirements.

[kimmosto]

I do not understand the hesitation and the negative viewpoint.

Available space (in pixels) has always been a problem with Enclosure tool and main program assuming that program should support height of 768px. Without changing UI of active filters to some kind of list or scrollable panel, there is room for just one more equalizer (by overlapping default margins few pixels per control).

List UI would be less visual and slower and more difficult to use. Scrollable panel may hide something when display or window is small. Will this be enough - the last to be added and the most important for us, or is it just redundancy because single user is not willing to use shelving LP and scale with supply voltage? How much free time should I use for this, and how to prevent VituixCAD to be another REW with hundreds of complex features without actual significance.

[witwald]

For example this driver:

Thank you. I follow your drift now.

In (too) many cases simulation with T/S and reality don't have much common.

I understand that, and I take your point. However, the countering point is that, in many cases, the simulation using T/S parameters allows a quick and easy exploration of the available design space. Ideas can be fleshed out and tried to establish their workabilty and usefulness, and then quickly and easily shared with others who have an interest in such solutions.

Why simulation should be boosted with features which don't help to represent reality.

Ostensibly, this is really being much too harsh...I would equally argue that the features I have identified would be useful in representing reality, in much the same way the existing features help. I do not understand the hesitation and the negative viewpoint.

Of course VituixCAD has possibility to include traced or downloaded acoustical measurement of the driver, but combining of simulation and datasheet response and baffle step response and XO filter is NOT done in Enclosure tool.

Agreed. But the request is to be able to perform a simpler, idealised analysis...

So Enclosure tool does not really need more EQ features than for testing SPL/excursion capacity and co-operation of impedance curve and typical passive network.

I beg to differ, as the features I have requested would help greatly, without adding any extra complexity.

[kimmosto]

I don't follow what you are trying to say here. Can you please elaborate a little?

For example this driver:



In (too) many cases simulation with T/S and reality don't have much common. Why simulation should be boosted with features which don't help to represent reality. Of course VituixCAD has possibility to include traced or downloaded acoustical measurement of the driver, but combining of simulation and datasheet response and baffle step response and XO filter is NOT done in Enclosure tool. So Enclosure tool does not really need more EQ features than for testing SPL/excursion capacity and co-operation of impedance curve and typical passive network. The second one can be done with the main program too, but passive components in Filter tab enable faster testing and iteration.

[witwald]

Simple system simulator does not know for example how cone equalizes acoustical response...

I don't follow what you are trying to say here. Can you please elaborate a little?